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  • 1. Jaeken, Bart
    et al.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Artal, Pablo
    Fast scanning peripheral wave-front sensor for the human eye2011In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 19, no 8, p. 7903-7913Article in journal (Refereed)
    Abstract [en]

    We designed and built a fast scanning peripheral Hartmann-Shack (HS) wave-front sensor to measure the off-axis wave-front aberrations in the human eye. The new instrument is capable of measuring the optical quality over the central 80 degrees horizontal visual field in 1.8 seconds with an angular resolution of 1 degrees. The subject has an open field of view without any moving elements in the line-of-sight and the head is kept in place by a head-chin rest. The same efficiency, reliability and measurement quality as the current static HS sensor were found but with much higher acquisition speed and comfort for the patients. This instrument has the potential to facilitate and improve future research on the peripheral optical quality of the eye in large groups of subjects.

  • 2. Jaeken, Bart
    et al.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Artal, Pablo
    Peripheral aberrations in the human eye for different wavelengths: off-axis chromatic aberration2011In: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 28, no 9, p. 1871-1879Article in journal (Refereed)
    Abstract [en]

    The interest in the eye's off-axis aberrations has increased strongly. On-axis the conversion of the aberration magnitude between different wavelengths is well known. We verified if this compensation is correct also for off-axis measurements by building a wavelength tunable peripheral Hartmann-Shack sensor and measuring 11 subjects out to +/- 30 degrees in the horizontal visual field. At the fovea, an average longitudinal chromatic aberration of 1D between red (671 nm) and blue (473 nm) light was found, and it increased slightly with eccentricity (up to 1.2D). A similar trend was measured for astigmatism as a function of wavelength (increase similar to 0.15D). Computational ray tracing in model eyes showed that the origin of the small increase of chromatic aberrations with eccentricity is the change of the oblique power of the refractive surfaces in the eye. Factors related to increase of axial length and refractive index of the eye were found to have a very small influence.

  • 3. Lakshminarayanan, Vasudevan
    et al.
    Varadharajan, L. Srinivasa
    Diaz-Santana, Luis
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Vision Science and Ophthalmic Optics2011In: Journal of Modern Optics, ISSN 0950-0340, E-ISSN 1362-3044, Vol. 58, no 19-20, p. 1679-1680Article in journal (Other academic)
  • 4. Lewis, Peter
    et al.
    Baskaran, Karthikeyan
    Rosén, Robert
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Gustafsson, Jörgen
    Objectively Determined Refraction Improves Peripheral Vision2014In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 91, no 7, p. 740-746Article in journal (Refereed)
    Abstract [en]

    Purpose. The purpose of this study was twofold: to verify a fast, clinically applicable method for determining off-axis refraction and to assess the impact of objectively obtained off-axis refractive correction on peripheral low-contrast visual acuity. Methods. We measured peripheral low-contrast resolution acuity with Gabor patches both with and without off-axis correction at 20 degrees in the nasal visual field of 10 emmetropic subjects; the correction was obtained using a commercial open-field Hartmann-Shack wavefront sensor, the COAS-HD VR aberrometer. Off-axis refractive errors were calculated for a 5-mm circular pupil inscribed within the elliptical wavefront by COAS using the instruments' inbuilt "Seidel sphere" method. Results. Most of the subjects had simple myopic astigmatism, at 20 degrees in the nasal visual field ranging from -1.00 to -2.00 DC, with axis orientations generally near 90 degrees. The mean uncorrected and corrected low-contrast resolution acuities for all subjects were 0.92 and 0.86 logMAR, respectively (an improvement of 0.06 logMAR). For subjects with a scalar power refractive error of 1.00 diopters or more, the average improvement was 0.1 logMAR. The observed changes in low-contrast resolution acuity were strongly correlated with off-axis astigmatism (Pearson r = 0.95; p < 0.0001), the J(180) cross-cylinder component (Pearson r = 0.82; p = 0.0034), and power scalar (Pearson r = -0.75; p = 0.0126). Conclusions. The results suggest that there are definite benefits in correcting even moderate amounts of off-axis refractive errors; in this study, as little as -1.50 DC of off-axis astigmatism gave improvements of up to a line in visual acuity. It may be even more pertinent for people who rely on optimal peripheral visual function, specifically those with central visual field loss; the use of open-field aberrometers could be clinically useful in rapidly determining off-axis refractive errors specifically for this patient group who are generally more challenging to refract.

  • 5.
    Lewis, Peter
    et al.
    Linnaeus Univ, Dept Med & Optometry, Kalmar, Sweden..
    Venkataraman, Abinaya Priya
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Contrast Sensitivity in Eyes with Central Scotoma: Effect of Stimulus Drift2018In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 95, no 4, p. 354-361Article in journal (Refereed)
    Abstract [en]

    SIGNIFICANCE: In the field of visual rehabilitation of patients with central visual field loss (CFL), knowledge on how peripheral visual function can be improved is essential. This study presents measurements of peripheral dynamic contrast sensitivity (with optical correction) for off-axis viewing angles in subjects with CFL. PURPOSE: Subjects with CFL rely on a peripheral preferred retinal locus (PRL) for many visual tasks. It is therefore important to ascertain that contrast sensitivity (CS) is maximized in the PRL. This study evaluates the effect of stimulus motion, in combination with optical correction, on CS in subjects with CFL. METHODS: The off-axis refractive errors in the PRL of five young CFL subjects were measured with a COAS open-view Hartmann-Shack aberrometer. Low-contrast (25% and 10%) and high-contrast resolution acuity for stationary gratings was assessed with and without optical correction. High-contrast resolution was also measured for gratings drifting at 7.5 Hz (within a fixed Gaussian window). Furthermore, resolution CS was evaluated for both stationary and moving gratings with optical correction for a total of two to three spatial frequencies per subject. RESULTS: High-contrast resolution acuity was relatively insensitive to stimulus drift motion of 7.5 Hz, whereas CS for gratings of 0.5 cycles per degree improved with drift for all subjects. Furthermore, both high- and low-contrast static resolution improved with optical correction. CONCLUSIONS: Just as for healthy eyes, stimulus motion of 7.5 Hz enhances CS for gratings of low spatial frequency also in the PRL of eyes with CFL. Concurrently, high-contrast resolution is unaffected by the 7.5-Hz drift but improves with off-axis optical correction. This highlights the importance of providing optimal refractive correction for subjects with CFL and that stimulus motion can be used to further enhance CS at low spatial frequencies.

  • 6. Lewis, Peter
    et al.
    Venkataraman, Abinaya Priya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Optical correction and stimulus motion improve peripheral vision in eyes with central scotomaManuscript (preprint) (Other academic)
  • 7.
    Lundström, Linda
    KTH, Superseded Departments, Physics.
    Measurement and evaluation of peripheral wavefront aberrations in the human eye2004Licentiate thesis, comprehensive summary (Other scientific)
  • 8.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Wavefront Aberrations and Peripheral Vision2007Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Failing eyesight causes a dramatic change in life. The aim of this project is to help people with large central visual field loss to better utilize their remaining vision. Central visual field loss means that the person has to rely on peripheral vision since the direct vision is lost, often due to a dysfunctional macula. In these cases, a full restoration of vision would require replacement or repair of the damaged retinal tissue, which is not yet possible. Instead, the present study seeks to improve peripheral vision by enhancing the image quality on the remaining functional part of the retina by optical corrections. The off-axis optics of the human eye often suffers from large optical errors, which together with the lower sampling density of the retina explain the limited visual function in the periphery. The dominating aberrations are field curvature and oblique astigmatism, which induce an effective eccentric refractive error. However, the irregular character of the aberrations and the limited neural function in the periphery will make it difficult to find the optimal refractive correction; the conventional subjective refraction, for example, is not suitable for subjects with large central visual field loss. Within the work of this thesis a Hartmann-Shack wavefront sensor has been constructed for oblique aberration measurements. Wavefront sensing is an objective method to assess detailed information about the optical errors in the human eye. Theory and methods have been developed to allow accurate off-axis measurements of the large aberrations, enable eccentric fixation, and handle the elliptical pupil. The study has mainly concentrated on sphero-cylindrical correction of peripheral vision. Peripheral resolution and detection acuity thresholds have been evaluated for seven subjects with central visual field loss and ten control subjects with normal vision. Five of the subjects with field loss showed improved resolution acuity with eccentric refractive correction compared to their habitual central correction, whereas little change was found for the control subjects. These results demonstrate that correction of peripheral optical errors can be beneficial to people with large central visual field loss in situations where a normal healthy eye does not experience any improvements. In conclusion, it is worthwhile to investigate the peripheral refractive errors in low-vision rehabilitation of central visual field loss and prescribe spectacle correction when those errors are large.

  • 9.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Gustafsson, Jörgen
    Rehabilitation Engineering Research, Department of Design Science, Lund University.
    Svensson, Ingrid
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Assessment of objective and subjective eccentric refraction2005In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 82, no 4, p. 298-306Article in journal (Refereed)
    Abstract [en]

    Purpose. When performing perimetry, refracting subjects with central visual field loss, and in emmetropization studies, it is important to accurately measure peripheral refractive errors. Traditional methods for foveal refraction often give uncertain results in eccentric angles as a result of the large aberrations and the reduced retinal function. The aim of this study is therefore to compare and evaluate four methods for eccentric refraction. Methods. Four eccentric methods were tested on 50 healthy subjects: one novel subjective procedure, optimizing the detection contrast sensitivity with different trial lenses, and three objective ones: photorefraction with a PowerRefractor, wavefront measurements with a Hartmann-Shack sensor, and retinoscopy. The peripheral refractive error in the horizontal nasal visual field of the right eye was measured in 20 degrees and 30 degrees. Results. In general, the eccentric refraction methods compared reasonably well. However, the following differences were noted. Retinoscopy showed a significant difference from the other methods in the axis of astigmatism. In 300 eccentric angle, it was not possible to measure 15 of the subjects with the PowerRefractor and the instrument also tended to underestimate high myopia (<-6 D). The Hartmann-Shack sensor showed a myopic shift of approximately 0.5 D in both eccentricities. The subjective method had a relatively larger spread. Conclusions. This study indicates that it is possible to assess the eccentric refraction with all methods. However, the Hartmann-Shack technique was found to be the most useful method. The agreement between the objective methods and the subjective eccentric refraction shows that detection contrast sensitivity in the periphery is affected by relatively small amounts of defocus.

  • 10.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Gustafsson, Jörgen
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Population distribution of wavefront aberrations in the peripheral human eye2009In: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 26, no 10, p. 2192-2198Article in journal (Refereed)
    Abstract [en]

    We present a population study of peripheral wavefront aberrations in large off-axis angles in terms of Zernike coefficients. A laboratory Hartmann-Shack sensor was used to assess the aberrations in 0 degrees, 20 degrees, and 30 degrees in the nasal visual field of 43 normal eyes. The elliptical pupil meant that the quantification could be done in different ways. The three approaches used were (1) over a circular aperture encircling the pupil, (2) over a stretched version of the elliptical pupil, and (3) over a circular aperture within the pupil (MATLAB conversion code given). Astigmatism (c(2)(2)) increased quadratically and coma (c(3)(1)) linearly with the horizontal viewing angle, whereas spherical aberration (c(4)(0)) decreased slightly toward the periphery. There was no correlation between defocus and angle, although some trends were found when the subjects were divided into groups depending on refractive error. When comparing results of different studies it has to be kept in mind that the coefficients differ depending on how the elliptical pupil is taken into consideration.

  • 11.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Gustafsson, Jörgen
    Vision Enabling Laboratory, School of Optometry, Kalmar University.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Vision evaluation of eccentric refractive correction2007In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 84, no 11, p. 1046-1052Article in journal (Refereed)
    Abstract [en]

    Purpose. This study investigates the benefits of eccentric refractive correction to resolution and detection thresholds in different contrasts for seven subjects with central visual field loss (CFL) and for four healthy control subjects with normal vision.

    Methods. Refractive correction in eccentric viewing angles, i.e., the preferred retinal location for the CFL subjects and 20 degrees off-axis for the control subjects, was assessed by photorefraction with the PowerRefractor instrument and by wavefront analysis using the Hartmann-Shack principle. The visual function with both eccentric and central corrections was evaluated using number identification and grating detection.

    Results. For the CFL subjects, the resolution and detection thresholds varied between individuals because of different preferred retinal locations and cause of visual field loss. However, all seven CFL subjects showed improved visual function for resolution and detection tasks with eccentric correction compared with central correction. No improvements in high-contrast resolution were found for the control subjects.

    Conclusions. These results imply that optical eccentric correction can improve the resolution acuity for subjects with CFL in situations where healthy eyes do not show any improvements.

  • 12.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Manzanera, Silvestre
    Laboratorio de Optica, Universidad de Murcia.
    Prieto, Pedro
    Laboratorio de Optica, Universidad de Murcia.
    Ayala, Diego
    Laboratorio de Optica, Universidad de Murcia.
    Gorceix, Nicolas
    Laboratorio de Optica, Universidad de Murcia.
    Gustafsson, Jörgen
    School of Optometry, Kalmar University.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Artal, Pablo
    Laboratorio de Optica, Universidad de Murcia.
    Effect of optical correction and remaining aberrations on peripheral resolution acuity in the human eye2007In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 15, no 20, p. 12654-12661Article in journal (Refereed)
    Abstract [en]

    Retinal sampling poses a fundamental limit to resolution acuity in the periphery. However, reduced image quality from optical aberrations may also influence peripheral resolution. In this study, we investigate the impact of different degrees of optical correction on acuity in the periphery. We used an adaptive optics system to measure and modify the off-axis aberrations of the right eye of six normal subjects at 20 degrees eccentricity. The system consists of a Hartmann-Shack sensor, a deformable mirror, and a channel for visual testing. Four different optical corrections were tested, ranging from foveal sphero-cylindrical correction to full correction of eccentric low- and high-order monochromatic aberrations. High-contrast visual acuity was measured in green light using a forced choice procedure with Landolt C's, viewed via the deformable mirror through a 4.8-mm artificial pupil. The Zernike terms mainly induced by eccentricity were defocus and with- and against-the-rule astigmatism and each correction condition was successfully implemented. On average, resolution decimal visual acuity improved from 0.057 to 0.061 as the total root-mean-square wavefront error changed from 1.01 mu m to 0.05 mu m. However, this small tendency of improvement in visual acuity with correction was not significant. The results suggest that for our experimental conditions and subjects, the resolution acuity in the periphery cannot be improved with optical correction.

  • 13.
    Lundström, Linda
    et al.
    Universidad de Murcia.
    Mira-Agudelo, Alejandro
    Artal, Pablo
    Peripheral optical errors and their change with accommodation differ between emmetropic and myopic eyes2009In: Journal of Vision, ISSN 1534-7362, E-ISSN 1534-7362, Vol. 9, no 6, p. 17-Article in journal (Refereed)
    Abstract [en]

    The progression of myopia is thought to be controlled by the retinal image quality, but its triggering factors are not yet well known. The differences between the peripheral optics in emmetropic and myopic eyes might explain why some eyes become myopic. The present study further investigates peripheral optical quality and how it is affected by accommodation. The refraction and aberrations of the right eyes of five emmetropes and five myopes were measured using a laboratory Hartmann-Shack wave front sensor, specially designed for peripheral measurements with an open field of view. The off-axis optical quality was assessed in steps of 10 degrees out to +/- 40 degrees horizontally and +/- 20 degrees vertically for two different states of accommodation (targets at 0.5 D and 4.0 D). As expected, the emmetropes had a higher relative peripheral myopia, that is, more positive c(2)(0) coefficient, than the myopes. The new results of this study are that this well-known difference was found to be asymmetric over the visual field and that it increased with accommodation. This increase was because the relative peripheral defocus profile of the myopes did not show a consistent change between far and near vision, whereas the emmetropes became relatively more myopic in the periphery with accommodation. These findings may indicate a difference between emmetropic and myopic eyes that could be an important clue to understand myopia progression.

  • 14.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Rosen, Robert
    Abbott Med Opt Groningen BV, Appl Res, Groningen, Netherlands..
    Van der Mooren, Marrie
    Abbott Med Opt Groningen BV, Appl Res, Groningen, Netherlands..
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Piers, Patricia A.
    Abbott Med Opt Groningen BV, Appl Res, Groningen, Netherlands..
    Low Amounts of Scattering Reduce Central as well as Peripheral Contrast Sensitivity2014In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 55, no 13Article in journal (Other academic)
  • 15.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Rosén, R.
    Peripheral aberrations2017In: Handbook of Visual Optics, Volume One: Fundamentals and Eye Optics, CRC Press , 2017, p. 313-335Chapter in book (Other academic)
    Abstract [en]

    The schematic of Figure 21.1 is highly simplified, assuming spherical and aligned surfaces. Nevertheless, it demonstrates two important facts regarding the optical errors of the human eye: that the blur increases with the off-axis angle to the object and that it depends on the size of the pupil. For instance, spherical aberration has a cubic dependence on pupil size and coma has a quadratic dependence, whereas TCA is independent. To exemplify, Figure 21.2 shows the variation in monochromatic image quality over the visual field measured for one subject. The following paragraphs will briefly explain the origin of the four largest peripheral aberrations, namely, astigmatism, field curvature, coma, and TCA. © 2017 by Taylor & Francis Group, LLC.

  • 16.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Rosén, Robert
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Baskaran, K.
    Jaeken, B.
    Gustafsson, J.
    Artal, P.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Symmetries in peripheral ocular aberrations2011In: Journal of Modern Optics, ISSN 0950-0340, E-ISSN 1362-3044, Vol. 58, no 19-20, p. 1690-1695Article in journal (Refereed)
    Abstract [en]

    A mirror symmetry in the aberrations between the left and right eyes has previously been found foveally, but while a similar symmetry for the peripheral visual field is likely, it has not been investigated. Nevertheless, the peripheral optical quality is often evaluated in only one eye, because it is more time efficient than analyzing the whole visual field of both eyes. This study investigates the correctness of such an approach by measuring the peripheral wavefront aberrations in both eyes of 22 subjects out to +/- 40 degrees horizontally. The largest aberrations (defocus, astigmatism, and coma) were found to be significantly correlated between the left and right eyes when comparing the same temporal or nasal angle. The slope of the regression line was close to +/- 1 (within 0.05) for these aberrations, with a negative slope for the horizontally odd aberrations, i.e. the left and right eyes are mirror symmetric. These findings justify that the average result, sampled in one of the two eyes of many subjects, can be generalized to the other eye as well.

  • 17.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Transformation of Zernike coefficients: scaled, translated, and rotated wavefronts with circular and elliptical pupils2007In: Journal of the Optical Society of America A, ISSN 0740-3232, Vol. 24, no 3, p. 569-577Article in journal (Refereed)
    Abstract [en]

    Zernike polynomials and their associated coefficients are commonly used to quantify the wavefront aberrations of the eye. When the aberrations of different eyes, pupil sizes, or corrections are compared or averaged, it is important that the Zernike coefficients have been calculated for the correct size, position, orientation, and shape of the pupil. We present the first complete theory to transform Zernike coefficients analytically with regard to concentric scaling, translation of pupil center, and rotation. The transformations are described both for circular and elliptical pupils. The algorithm has been implemented in MATLAB, for which the code is given in an appendix.

  • 18.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unwrapping Hartmann-Shack images from highly aberrated eyes using an iterative B-spline based extrapolation method2004In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 81, no 5, p. 383-388Article in journal (Refereed)
    Abstract [en]

    Purpose. When the wavefront aberrations of the eye are measured with a Hartmann-Shack (HS) sensor, the resulting spot pattern must be unwrapped, that is, for each lenslet the corresponding spot must be identified. This puts a limitation on the measurable amount of aberrations. To extend the range of an HS sensor, a powerful unwrapping algorithm has been developed. Methods. The unwrapping algorithm starts by connecting the central HS spots to the central lenslets. It then fits a B-spline function through a least squares estimate to the deviations of the central HS spots. This function is then extrapolated to find the expected locations of HS spots for the unconnected lenslets. The extrapolation is performed gradually in an iterative manner; the closest unconnected lenslets are extrapolated and connected, and then the B-spline function is least squares fitted to all connected HS spots and extrapolated again. Results. Wavefront aberrations from eyes with high aberrations can be successfully unwrapped with the developed algorithm. The dynamic range of a typical HS sensor increases 3.5 to 13 times compared with a simple unwrapping algorithm. Conclusions. The implemented algorithm is an efficient unwrapping tool and allows the use of lenslets with a low numerical aperture and thus gives a relatively higher accuracy of measurements of the ocular aberrations.

  • 19.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, Superseded Departments, Physics. KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Gustafsson, J
    Measuring peripheral wavefront aberrations in subjects with large central visual field loss2004In: OPHTHALMIC TECHNOLOGIES XIV / [ed] Manns, F; Soderberg, PG; Ho, A, BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING , 2004, Vol. 5314, p. 209-219Conference paper (Refereed)
    Abstract [en]

    In a previous study we have shown that correction of peripheral refractive errors can improve the remaining vision in the preferred retinal location (PRL) of subjects with large central visual field loss (CFL). Measuring peripheral refractive errors with traditional methods is often difficult due to the low visual acuity and large aberrations. Therefore a Hartmann-Shack (HS) sensor has been designed to measure peripheral wavefront aberrations in CFL subjects. Method: The HS sensor incorporates an eyetracker and analyzing software designed to handle large wavefront aberrations. To ensure that the measurement axis is aligned with the subject's PRL, a special fixation target has been developed. It consists of concentric rings surrounding the aperture of the HS together with a central fixation mark along the measurement axis. Results: Some initial measurements on subjects with CFL have been performed successfully. As a first step in improving the peripheral optics of the eye, the wavefront data have been used to calculate the subject's optimal eccentric refraction. Conclusion: Measuring the wavefront aberrations is a fast and easy way to assess the details of the optics in subjects with CFL. The wavefront data can then be used to better understand the problems of eccentric correction.

  • 20.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Gustafsson, Jörgen
    Lund University, Certec, Rehabilitation Engineering Research, Department of Design Sciences, Lund.
    Off-axis wave front measurements for optical correction in eccentric viewing2005In: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 10, no 3, p. 034002-1-034002-7Article in journal (Refereed)
    Abstract [en]

    In a previous study we have shown that correction of peripheral refractive errors can improve the remaining vision of subjects with large central visual field loss. Measuring peripheral refractive errors with traditional methods is often difficult due to low visual acuity and large aberrations. Therefore a Hartmann-Shack sensor has been designed to measure peripheral wave front aberrations in subjects using eccentric viewing. The sensor incorporates an eye tracker and analyzing software designed to handle large wave front aberrations and elliptic pupils. To ensure that the measurement axis is aligned with the direction of the subject's preferred retinal location, a special fixation target has been developed. It consists of concentric rings surrounding the aperture of the sensor together with a central fixation mark along the measurement axis. Some initial measurements on subjects using eccentric viewing have been performed successfully. As a first step in improving the peripheral optics of the eye, the wave front has been used to calculate the eccentric refraction. This refraction has been compared to the refraction found with the Power-Refractor instrument. Measuring the off-axis wave front is a fast way to assess the optical errors in the subject's eccentric viewing angle and to better understand the problems of eccentric correction.

  • 21.
    Lundström, Linda
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Venkataraman, Abinaya Priya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lewis, Peter R.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Spatiotemporal contrast sensitivity in the 10 degrees visual field2016In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 57, no 12Article in journal (Refereed)
  • 22. Marcos, S.
    et al.
    Werner, J. S.
    Burns, S. A.
    Merigan, W. H.
    Artal, P.
    Atchison, D. A.
    Hampson, K. M.
    Legras, R.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Yoon, G.
    Carroll, J.
    Choi, S. S.
    Doble, N.
    Dubis, A. M.
    Dubra, A.
    Elsner, A.
    Jonnal, R.
    Miller, D. T.
    Paques, M.
    Smithson, H. E.
    Young, L. K.
    Zhang, Y.
    Campbell, M.
    Hunter, J.
    Metha, A.
    Palczewska, G.
    Schallek, J.
    Sincich, L. C.
    Vision science and adaptive optics, the state of the field2017In: Vision Research, ISSN 0042-6989, E-ISSN 1878-5646, Vol. 132, p. 3-33Article in journal (Refereed)
    Abstract [en]

    Adaptive optics is a relatively new field, yet it is spreading rapidly and allows new questions to be asked about how the visual system is organized. The editors of this feature issue have posed a series of question to scientists involved in using adaptive optics in vision science. The questions are focused on three main areas. In the first we investigate the use of adaptive optics for psychophysical measurements of visual system function and for improving the optics of the eye. In the second, we look at the applications and impact of adaptive optics on retinal imaging and its promise for basic and applied research. In the third, we explore how adaptive optics is being used to improve our understanding of the neurophysiology of the visual system.

  • 23. Mira-Agudelo, Alejandro
    et al.
    Lundström, Linda
    Universidad de Murcia.
    Artal, Pablo
    Temporal dynamics of ocular aberrations: monocular vs binocular vision2009In: Ophthalmic & physiological optics, ISSN 0275-5408, E-ISSN 1475-1313, Vol. 29, no 3, p. 256-263Article in journal (Refereed)
    Abstract [en]

    The temporal dynamics of ocular aberrations are important for the evaluation of, e.g. the accuracy of aberration estimates, the correlation to visual performance, and the requirements for real-time correction with adaptive optics. Traditionally, studies on the eye’s dynamic behavior have been performed monocularly, which might have affected the results. In this study we measured aberrations and their temporal dynamics both monocularly and binocularly in the relaxed and accommodated state for six healthy subjects. Temporal frequencies up to 100 Hz were measured with a fast-acquisition Hartmann–Shack wavefront sensor having an open field-of-view configuration which allowed fixation to real targets. Wavefront aberrations were collected in temporal series of 5 s duration during binocular and monocular vision with fixation targets at 5 m and 25 cm distance. As expected, a larger temporal variability was found in the root-mean-square wavefront error when the eye accommodated, mainly for frequencies lower than 30 Hz. A statistically-significant difference in temporal behavior between monocular and binocular viewing conditions was found. However, on average it was too small to be of practical importance, although some subjects showed a notably higher variability for the monocular case during near vision. We did find differences in pupil size with mono- and binocular vision but the pupil size temporal dynamics did not behave in the same way as the aberrations’ dynamics.

  • 24.
    Papadogiannis, Petros
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Romashchenko, Dmitry
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    Influence of optical defocus on peripheral vision with and without aberrations2018In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 59, no 9Article in journal (Refereed)
  • 25. Pettersson, Anna Lindskoog
    et al.
    Ramsay, Marika Wahlberg
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Rosén, Robert
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Nilsson, Maria
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Brautaset, Rune
    Accommodation in young adults wearing aspheric multifocal soft contact lenses2011In: Journal of Modern Optics, ISSN 0950-0340, E-ISSN 1362-3044, Vol. 58, no 19-20, p. 1804-1808Article in journal (Refereed)
    Abstract [en]

    The aim of the present project was to investigate accommodative behavior in young adults and adolescents fitted with an aspheric multifocal (center distance) contact lens with focus on evaluating whether these lenses can be an alternative treatment for subjects in which a reduced level of blur and thereby accommodation in near vision is aimed at. Twenty normal subjects aged between 21 and 35 years participated in the study. Aberrometry was perfomed using a Zywave (TM) aberrometer, first on the uncorrected eyes of all subjects, and again while the subjects wore a multifocal contact lens with a +1.00 add. A Shin-Nippon N Vision-K 5001 Autoref-Keratometer was used to measure accommodative response with two different refractive corrections: (1) habitual spectacle correction only, and (2) habitual correction and a aspheric multifocal (center distance) contact lens. Four hours of adaptation to the lens was allowed. The lag when wearing only the habitual spectacles was compared with the lag while wearing both the habitual spectacles and the aspheric multifocal contact lens. The mean lag of accommodation for the subject group was 0.85 D (+/-0.57 SD) and 0.75 D (+/-0.52 SD) without and with the multifocal lens, respectively. Statistical analyses showed no difference in lag (t = 0.8479, p = 0.407) with and without the lens. In conclusion, young normal subjects do not relax accommodation when fitted with aspheric multifocal center distance lenses when the addition is +1.00. It is therefore unlikely that subjects with accommodative ability, in whom the treatment purpose is to reduce blur and thereby accommodation, can be effectively treated with such lenses.

  • 26.
    Romashchenko, Dmitry
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Rosen, Robert
    Johnson & Johnson Vis, R&D, Groningen, Netherlands..
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Peripheral refraction and higher order aberrations2019In: Clinical and experimental optometry, ISSN 0816-4622, E-ISSN 1444-0938Article in journal (Refereed)
    Abstract [en]

    Peripheral image quality influences several aspects of human vision. Apart from off-axis visual functions, the manipulation of peripheral optical errors is widely used in myopia control interventions. This, together with recent technological advancements enabling the measurement of peripheral errors, has inspired many studies concerning off-axis optical aberrations. However, direct comparison between these studies is often not straightforward. To enable between-study comparisons and to summarise the current state of knowledge, this review presents population data analysed using a consistent approach from 16 studies on peripheral ocular optical quality (in total over 2,400 eyes). The presented data include refractive errors and higher order monochromatic aberrations expressed as Zernike co-efficients (reported in a subset of the studies) over the horizontal visual field. Additionally, modulation transfer functions, describing the monochromatic image quality, are calculated using individual wavefront data from three studies. The analysed data show that optical errors increase with increasing eccentricity as expected from theoretical modelling. Compared to emmetropes, myopes tend to have more hypermetropic relative peripheral refraction over the horizontal field and worse image quality in the near-periphery of the nasal visual field. The modulation transfer functions depend considerably on pupil shape (for angles larger than 30 degrees) and to some extent, the number of Zernike terms included. Moreover, modulation transfer functions calculated from the average Zernike co-efficients of a cohort are artificially inflated compared to the average of individual modulation transfer functions from the same cohort. The data collated in this review are important for the design of ocular corrections and the development and assessment of optical eye models.

  • 27.
    Rosén, Robert
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Jaeken, B.
    Lindskoog Petterson, A.
    Artal, P.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Evaluating the peripheral optical effect of multifocal contact lenses2012In: Ophthalmic & physiological optics, ISSN 0275-5408, E-ISSN 1475-1313, Vol. 32, no 6, p. 527-534Article in journal (Refereed)
    Abstract [en]

    Purpose: Multifocal soft contact lenses have been used to decrease the progression of myopia, presumably by inducing relative peripheral myopia at the same time as the central image is focused on the fovea. The aim of this study was to investigate how the peripheral optical effect of commercially available multifocal soft contact lenses can be evaluated from objective wavefront measurements. Methods: Two multifocal lenses with high and low add and one monofocal design were measured over the ±40° horizontal field, using a scanning Hartmann-Shack wavefront sensor on four subjects. The effect on the refractive shift, the peripheral image quality, and the depth of field of the lenses was evaluated using the area under the modulation transfer function as the image quality metric. Results: The multifocal lenses with a centre distance design and 2 dioptres of add induced about 0.50 dioptre of relative peripheral myopia at 30° in the nasal visual field. For larger off-axis angles the border of the optical zone of the lenses severely degraded image quality. Moreover, these multifocal lenses also significantly reduced the image quality and increased the depth of field for angles as small as 10°-15° Conclusions: The proposed methodology showed that the tested multifocal soft contact lenses gave a very small peripheral myopic shift in these four subjects and that they would need a larger optical zone and a more controlled depth of field to explain a possible treatment effect on myopia progression.

  • 28.
    Rosén, Robert
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Adaptive optics for peripheral vision2012In: Journal of Modern Optics, ISSN 0950-0340, E-ISSN 1362-3044, Vol. 59, no 12, p. 1064-1070Article in journal (Refereed)
    Abstract [en]

    Understanding peripheral optical errors and their impact on vision is important for various applications, e.g. research on myopia development and optical correction of patients with central visual field loss. In this study, we investigated whether correction of higher order aberrations with adaptive optics (AO) improve resolution beyond what is achieved with best peripheral refractive correction. A laboratory AO system was constructed for correcting peripheral aberrations. The peripheral low contrast grating resolution acuity in the 20 nasal visual field of the right eye was evaluated for 12 subjects using three types of correction: refractive correction of sphere and cylinder, static closed loop AO correction and continuous closed loop AO correction. Running AO in continuous closed loop improved acuity compared to refractive correction for most subjects (maximum benefit 0.15logMAR). The visual improvement from aberration correction was highly correlated with the subject's initial amount of higher order aberrations (p=0.001, R 2=0.72). There was, however, no acuity improvement from static AO correction. In conclusion, correction of peripheral higher order aberrations can improve low contrast resolution, provided refractive errors are corrected and the system runs in continuous closed loop.

  • 29.
    Rosén, Robert
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Influence of Optical Defocus on Peripheral Vision2011In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 52, no 1, p. 318-323Article in journal (Refereed)
    Abstract [en]

    PURPOSE. Peripheral optical corrections are often thought to give few visual benefits beyond improved detection acuity. However, patients with central visual field loss seem to benefit from peripheral correction, and animal studies suggest a role for peripheral vision in the development of myopia. This study was conducted to bridge this gap by systematically studying the sensitivity to optical defocus in a wide range of peripheral visual tasks. METHODS. The spatial frequency threshold for detection and resolution in high and low contrast with stationary and drifting gratings were measured off-axis (20 nasal visual field) in five subjects with a peripheral optical correction that was varied systematically +/- 4 D. RESULTS. All visual tasks, except high-contrast resolution, were sensitive to optical defocus, particularly low-contrast resolution with an increase of up to 0.227 logMAR/D. The two myopic subjects exhibited a very low sensitivity to defocus by negative lenses for low-contrast tasks, whereas all subjects were equally affected by myopic defocus. Contrary to expectations, drifting gratings made little difference overall. CONCLUSIONS. Optical defocus as low as 1 D has a large impact on most peripheral visual tasks, with high-contrast resolution being the exception. Since the everyday visual scenery consists of objects at different contrast levels, it is understandable that persons with central visual field loss are helped by correction of peripheral refractive errors. The asymmetry in sensitivity to peripheral optical defocus in low-contrast tasks that was experienced by the myopic subjects in this study merits further investigation.

  • 30.
    Rosén, Robert
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Sign-Dependent Sensitivity to Peripheral Defocus for Myopes due to Aberrations2012In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 53, no 11, p. 7176-7182Article in journal (Refereed)
    Abstract [en]

    PURPOSE. Animal studies suggest that the periphery of the eye plays a major role in emmetropization. It is also known that human myopes tend to have relative peripheral hyperopia compared to the foveal refraction. This study investigated peripheral sensitivity to defocus in human subjects, specifically whether myopes are less sensitive to negative than to positive defocus. METHODS. Sensitivity to defocus (logMAR/D) in the 20 degrees nasal visual field was determined in 16 emmetropes (6 males and 10 females, mean spherical equivalent -0.03 +/- 0.13 D, age 30 +/- 6 10 years) and 16 myopes (3 males and 13 females, mean spherical equivalent -3.25 +/- 2 D, age 25 +/- 6 years) using the slope of through-focus low-contrast resolution (10%) acuity measurements. Peripheral wavefront measurements at the same angle were obtained from 13 of the myopes and 9 of the emmetropes, from which the objective depth of field was calculated by assessing the area under the modulation transfer function (MTF) with added defocus. The difference in depth of field between negative and positive defocus was taken as the asymmetry in depth of field. RESULTS. Myopes were significantly less sensitive to negative than to positive defocus (median difference in sensitivity 0.06 logMAR/D, P = 0.023). This was not the case for emmetropes (median difference -0.01 logMAR/D, P = 0.382). The difference in sensitivity between positive and negative defocus was significantly larger for myopes compared to emmetropes (P = 0.031). The correlation between this difference in sensitivity and objective asymmetry in depth of field due to aberrations was significant for the whole group (R-2 = 0.18, P 0.02) and stronger for myopes (R-2 = 0.8, P < 0.01). CONCLUSIONS. We have shown that myopes, in general, are less sensitive to negative than to positive defocus, which can be linked to their aberrations. This finding is consistent with a previously proposed model of eye growth that is driven by the difference between tangential and radial peripheral blur.

  • 31.
    Rosén, Robert
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Atchison, D. A.
    Have we misinterpreted the study of Hoogerheide et al. (1971)?2012In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 89, no 8, p. 1235-1237Article in journal (Refereed)
    Abstract [en]

    In 1971, Rempt et al. reported peripheral refraction patterns (skiagrams) along the horizontal visual field in 442 people. Later in the same year, Hoogerheide et al. used skiagrams in combination with medical records to relate skiagrams in emmetropes and hyperopes to progression of myopia in young adults. The two articles have spurred interest in peripheral refraction in the past decade. We challenge the understanding that their articles provide evidence that the peripheral refraction pattern along the horizontal visual field is predictive of whether or not a person develops myopia. First, although it has been generally assumed that the skiagrams were measured before the changes in refraction were monitored, Hoogerheide et al. did not state that this was the case. Second, if the skiagrams were obtained at an initial examination and given the likely rates of recruitment and successful completion of training, the study must have taken place during a period of 10 to 15 years; it is much more likely that Hoogerheide et al. measured the skiagrams in a shorter period. Third, despite there being many more emmetropes and hyperopes in the Rempt et al. article than there are in the Hoogerheide et al. article, the number of people in two types of "at risk" skiagrams is greater in the latter; this is consistent with the central refraction status being reported from an earlier time by Hoogerheide et al. than by Rempt et al. In summary, we believe that the skiagrams reported by Hoogerheide et al. were taken at a later examination, after myopia did or did not occur, and that the refraction data from the initial examination were retrieved from the medical archives. Thus, this work does not provide evidence that peripheral refraction pattern is indicative of the likely development of myopia.

  • 32.
    Rosén, Robert
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Venkataraman, Abinaya Priya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Winter, Simon
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Quick contrast sensitivity measurements in the periphery2014In: Journal of Vision, ISSN 1534-7362, E-ISSN 1534-7362, Vol. 14, no 8Article in journal (Refereed)
    Abstract [en]

    Measuring the contrast sensitivity function (CSF) in the periphery of the eye is complicated. The lengthy measurement time precludes all but the most determined subjects. The aim of this study was to implement and evaluate a faster routine based on the quick CSF method (qCSF) but adapted to work in the periphery. Additionally, normative data is presented on neurally limited peripheral CSFs. A peripheral qCSF measurement using 100 trials can be performed in 3 min. The precision and accuracy were tested for three subjects under different conditions (number of trials, peripheral angles, and optical corrections). The precision for estimates of contrast sensitivity at individual spatial frequencies was 0.07 log units when three qCSF measurements of 100 trials each were averaged. Accuracy was estimated by comparing the qCSF results with a more traditional measure of CSF. Average accuracy was 0.08 log units with no systematic error. In the second part of the study, we collected three CSFs of 100 trials for six persons in the 20 degrees nasal, temporal, inferior, and superior visual fields. The measurements were performed in an adaptive optics system running in a continuous closed loop. The Tukey HSD test showed significant differences (p < 0.05) between all fields except between the nasal and the temporal fields. Contrast sensitivity was higher in the horizontal fields, and the inferior field was better than the superior. This modified qCSF method decreases the measurement time significantly and allows otherwise unfeasible studies of the peripheral CSF.

  • 33.
    Rosén, Robert
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Venkataraman, Abinaya Priya
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Winter, Simon
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Quick measurements of contrast sensitivity in the peripheral visual field2014In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 55, no 13Article in journal (Other academic)
  • 34. Roth, Lina S. V.
    et al.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Kelber, Almut
    Kroger, Ronald H. H.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    The pupils and optical systems of gecko eyes2009In: Journal of Vision, ISSN 1534-7362, E-ISSN 1534-7362, Vol. 9, no 3Article in journal (Refereed)
    Abstract [en]

    The nocturnal helmet gecko, Tarentola chazaliae, discriminates colors in dim moonlight when humans are color blind. The sensitivity of the helmet gecko eye has been calculated to be 350 times higher than human cone vision at the color vision threshold. The optics and the large cones of the gecko are important reasons why they can use color vision at low light intensities. Using photorefractometry and an adapted laboratory Hartmann-Shack wavefront sensor of high resolution, we also show that the optical system of the helmet gecko has distinct concentric zones of different refractive powers, a so-called multifocal optical system. The intraspecific variation is large but in most of the individuals studied the zones differed by 15 diopters. This is of the same magnitude as needed to focus light of the wavelength range to which gecko photoreceptors are most sensitive. We compare the optical system of the helmet gecko to that of the diurnal day gecko, Phelsuma madagascariensis grandis. The optical system of the day gecko shows no signs of distinct concentric zones and is thereby monofocal.

  • 35. van der Mooren, M.
    et al.
    Rosén, R.
    Franssen, L.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Piers, P.
    Degradation of visual performance with increasing levels of retinal stray light2016In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 57, no 13, p. 5443-5448Article in journal (Refereed)
    Abstract [en]

    PURPOSE. To quantify the effect of induced stray light on halo size, luminance threshold, and contrast sensitivity. METHODS. Retinal stray light was induced in five healthy subjects using different photographic filters. The stray light induced ranged from levels observed in intraocular lenses (IOLs) with glistenings (low) to cataract level (high). The visual impact was measured for halo size, luminance detection threshold, and contrast sensitivity with and without a glare source. RESULTS. The amount of retinal stray light induced by the different filters was similar when measured using the psychophysical method and the optical bench method. Low amounts of induced stray light cause the halo size to increase by 21%, the luminance detection threshold to increase by 156%, and contrast sensitivity to decrease by 10% to 21% dependent on spatial frequency and presence of a glare source. The visual impact percentages for high amounts of induced stray light were, respectively, 76%, 2130%, and 30% to 49%. In the presence of a glare source, contrast sensitivity losses were larger and shifted to lower spatial frequencies. CONCLUSIONS. Low levels of retinal stray light can cause significant increases in halo sizes, elevations in luminance detection thresholds, and reductions in contrast sensitivity whether or not a glare source is present.

  • 36.
    Van der Mooren, Marrie
    et al.
    AMO Groningen BV, Res & Dev, Groningen, Netherlands..
    Rosen, Robert
    AMO Groningen BV, Res & Dev, Groningen, Netherlands..
    Franssen, Luuk
    AMO Groningen BV, Res & Dev, Groningen, Netherlands..
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Piers, Patricia A.
    AMO Groningen BV, Res & Dev, Groningen, Netherlands..
    Prediction of contrast sensitivity in the presence of glare2017In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 58, no 8Article in journal (Other academic)
  • 37. Van der Mooren, Marrie
    et al.
    Steinert, Roger F.
    Tyson, Farrell
    Rosen, Robert
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Piers, Patricia A.
    Understanding visual complaints of two intraocular lens explant cases2015In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 56, no 7Article in journal (Refereed)
    Abstract [en]

     Purpose 

    In two different cases, multifocal intraocular lenses (MFIOLs) were explanted due to visual complications related to the presence of micro-vacuoles in the optic body. These micro-vacuoles cause straylight, which resulted in complaints of hazy and blurry vision. The purpose of this study is to objectively measure and systematically quantify the visual impact of this straylight. The study will thereby give a better understanding of the origin of reported visual complaints when micro-vacuoles are present.

     Methods 

    The amount of straylight in the two explanted MFIOLs was measured using an in-vitro setup and quantified using the scattering parameter s. To determine the impact of straylight on vision, photographic filters characterized in the same in-vitro setup were used to induce straylight on five subjects. Four different psychophysical visual tests were used: halo size, luminance detection with a glare source, and contrast sensitivity (CS) with and without the presence of glare. For all tests, the impact was modeled as a linear interpolation of the logarithm of the test score against the logarithm of the scattering parameter, log(s).

     Results 

    The straylight measured by the in-vitro setup was 6 deg2/sr for case 1 and 4 deg2/sr for case 2. Assuming a base straylight level of 1.1 log(s), the induced increase for the two patients was 0.17 log(s) and 0.12 log(s) respectively.<br /> The impact for the visual tests per unit of log(s) was the following: for halo size, 0.55 log(degrees)/log(s); for luminance detection 2.72 log(cd/m2)/log(s); for CS without glare, 0.33 log(CS)/log(s); and for CS with glare, 0.58 log(CS)/log(s). The induced straylight for the two explanted MFIOLs therefore corresponds to an increase of halo size of 24% and 16%, a luminance detection threshold increase of 190% and 112%, a contrast sensitivity decrease of 12% and 9% without a glare source, and a contrast sensitivity decrease of 20% and 9% with a glare source.

     Conclusions 

    In the explanted MFIOLs we could objectively measure straylight. This straylight corresponds psychophysically to increases in halo size, loss of luminance sensitivity and decrease in contrast sensitivity. Among the visual tests, measurement of luminance detection showed the highest sensitivity.

  • 38.
    Venkataraman, Abinaya Priya
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Lewis, Peter R.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Optical Correction and Stimulus Motion to Improve Vision in Eccentric Preferred Retinal Locus2016In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 57, no 12Article in journal (Refereed)
  • 39.
    Venkataraman, Abinaya Priya
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lewis, Peter
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Peripheral contrast sensitivity for drifting stimuliManuscript (preprint) (Other academic)
  • 40.
    Venkataraman, Abinaya Priya
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Winter, Simon
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics. Royal Inst Technol, KTH, Biomed & Xray Phys, Stockholm, Sweden..
    Small and Large Field Blur Adaptation: Foveal and Peripheral Contrast Sensitivity Changes2014In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 55, no 13Article in journal (Other academic)
  • 41.
    Venkataraman, Abinaya Priya
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Papadogiannis, Petros
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Romashchenko, Dmitry
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Winter, Simon
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Peripheral resolution and contrast sensitivity: effects of monochromatic and chromatic aberrations2019In: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 36, no 4, p. B52-B57Article in journal (Refereed)
    Abstract [en]

    Correction and manipulation of peripheral refractive errors are indispensable for people with central vision loss and in optical interventions for myopia control. This study investigates further enhancements of peripheral vision by compensating for monochromatic higher-order aberrations (with an adaptive optics system) and chromatic aberrations (with a narrowband green filter, 550 nm) in the 20 degrees nasal visual field. Both high-contrast detection cutoff and contrast sensitivity improved with optical correction. This improvement was most evident for gratings oriented perpendicular to the meridian due to asymmetric optical errors. When the natural monochromatic higher-order aberrations are large, resolution of 10% contrast oblique gratings can also be improved with correction of these errors. Though peripheral vision is mainly limited by refractive errors and neural factors, higher-order aberration correction beyond conventional refractive errors can still improve peripheral vision under certain circumstances.

  • 42.
    Venkataraman, Abinaya Priya
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Radhakrishnan, A.
    Dorronsoro, C.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Marcos, S.
    Role of parafovea in blur perception2017In: Vision Research, ISSN 0042-6989, E-ISSN 1878-5646, Vol. 138, p. 59-65Article in journal (Refereed)
    Abstract [en]

    The blur experienced by our visual system is not uniform across the visual field. Additionally, lens designs with variable power profile such as contact lenses used in presbyopia correction and to control myopia progression create variable blur from the fovea to the periphery. The perceptual changes associated with varying blur profile across the visual field are unclear. We therefore measured the perceived neutral focus with images of different angular subtense (from 4° to 20°) and found that the amount of blur, for which focus is perceived as neutral, increases when the stimulus was extended to cover the parafovea. We also studied the changes in central perceived neutral focus after adaptation to images with similar magnitude of optical blur across the image or varying blur from center to the periphery. Altering the blur in the periphery had little or no effect on the shift of perceived neutral focus following adaptation to normal/blurred central images. These perceptual outcomes should be considered while designing bifocal optical solutions for myopia or presbyopia.

  • 43.
    Venkataraman, Abinaya Priya
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Radhakrishnan, Aiswaryah
    Dorronsoro, Carlos
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Marcos, Susana
    Effect of parafovea on blur perceptionManuscript (preprint) (Other academic)
  • 44.
    Venkataraman, Abinaya Priya
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Winter, Simon
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Rosén, Robert
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Choice of grating orientation for evaluation of peripheral vision2016In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 93, no 6, p. 567-574Article in journal (Refereed)
    Abstract [en]

    Purpose: Peripheral resolution acuity depends on the orientation of the stimuli. However, it is uncertain if such a meridional effect also exists for peripheral detection tasks because they are affected by optical errors. Knowledge of the quantitative differences in acuity for different grating orientations is crucial for choosing the appropriate stimuli for evaluations of peripheral resolution and detection tasks. We assessed resolution and detection thresholds for different grating orientations in the peripheral visual field.

    Methods: Resolution and detection thresholds were evaluated for gratings of four different orientations in eight different visual field meridians in the 20-deg visual field in white light. Detection measurements in monochromatic light (543 nm; bandwidth, 10 nm) were also performed to evaluate the effects of chromatic aberration on the meridional effect. A combination of trial lenses and adaptive optics system was used to correct the monochromatic lower- and higher-order aberrations.

    Results: For both resolution and detection tasks, gratings parallel to the visual field meridian had better threshold compared with the perpendicular gratings, whereas the two oblique gratings had similar thresholds. The parallel and perpendicular grating acuity differences for resolution and detection tasks were 0.16 logMAR and 0.11 logMAD, respectively. Elimination of chromatic errors did not affect the meridional preference in detection acuity.

    Conclusions: Similar to peripheral resolution, detection also shows a meridional effect that appears to have a neural origin. The threshold difference seen for parallel and perpendicular gratings suggests the use of two oblique gratings as stimuli in alternative forced-choice procedures for peripheral vision evaluation to reduce measurement variation.

  • 45.
    Venkataraman, Abinaya Priya
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Winter, Simon
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Blur adaptation: Contrast sensitivity changes and stimulus extent2015In: Vision Research, ISSN 0042-6989, E-ISSN 1878-5646, Vol. 110, no PA, p. 100-106Article in journal (Refereed)
    Abstract [en]

    A prolonged exposure to foveal defocus is well known to affect the visual functions in the fovea. However, the effects of peripheral blur adaptation on foveal vision, or vice versa, are still unclear. In this study, we therefore examined the changes in contrast sensitivity function from baseline, following blur adaptation to small as well as laterally extended stimuli in four subjects. The small field stimulus (7.5° visual field) was a 30. min video of forest scenery projected on a screen and the large field stimulus consisted of 7-tiles of the 7.5° stimulus stacked horizontally. Both stimuli were used for adaptation with optical blur (+2.00. D trial lens) as well as for clear control conditions. After small field blur adaptation foveal contrast sensitivity improved in the mid spatial frequency region. However, these changes neither spread to the periphery nor occurred for the large field blur adaptation. To conclude, visual performance after adaptation is dependent on the lateral extent of the adaptation stimulus.

  • 46.
    Winter, Simon
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Fathi, Mohammad Taghi
    Venkataraman, Abinaya Priya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Rosén, Robert
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Seidemann, Anne
    Esser, Gregor
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Effect of induced transverse chromatic aberration on peripheral vision2015In: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 32, no 10, p. 1764-1771Article in journal (Refereed)
    Abstract [en]

    Transverse chromatic aberration (TCA) is one of the largest optical errors affecting the peripheral image quality in the human eye. However, the effect of chromatic aberrations on our peripheral vision is largely unknown. This study investigates the effect of prism-induced horizontal TCA on vision, in the central as well as in the 20 degrees nasal visual field, for four subjects. Additionally, the magnitude of induced TCA (in minutes of arc) was measured subjectively in the fovea with a Vernier alignment method. During all measurements, the monochromatic optical errors of the eye were compensated for by adaptive optics. The average reduction in foveal grating resolution was about 0.032 +/- 0.005 logMAR/arcmin of TCA (mean +/- std). For peripheral grating detection, the reduction was 0.057 +/- 0.012 logMAR/arcmin. This means that the prismatic effect of highly dispersive spectacles may reduce the ability to detect objects in the peripheral visual field.

  • 47.
    Winter, Simon
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics. Royal Inst Technol, Biomed & Xray Phys, Stockholm, Sweden..
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Fathi, Mohammad Taghi
    Rodenstock GmbH, Corp Res & Dev, Munich, Germany..
    Venkataraman, Abinaya Priya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Seidemann, Anne
    Rodenstock GmbH, Corp Res & Dev, Munich, Germany..
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Horizontally induced transverse chromatic aberration reduces peripheral acuity2014In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 55, no 13Article in journal (Other academic)
  • 48.
    Winter, Simon
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Sabesan, Ramkumar
    Tiruveedhula, Pavan N.
    Privitera, Claudio
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Roorda, Austin
    Objective measurements of transverse chromatic aberration across the visual field of the human eye2015In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 56, no 7Article in journal (Refereed)
    Abstract [en]

    Purpose: The purpose of this study was to use a new image-based technique to make the first-ever objective measures of TCA at different eccentricities within the human visual field.

    Methods: TCA was measured at visual field angles of 0.5, 2.5, 5, 7.5, 10, 12.5, and 15 degrees from foveal fixation in the right eye of 4 subjects. Interleaved retinal images were taken at wavelengths 543 nm and 842 nm in an adaptive optics scanning laser ophthalmoscope (AOSLO) and were cross-correlated according to methods described in Harmening et al., Biomed Opt Express, 2012. Pupil alignment was controlled with a pupil-camera. To obtain true measures of human eye TCA, the contributions of the AOSLO system TCA were measured using an on-axis aligned model eye and subtracted from the human eye data.

    Results: The system TCA was stable at around 3 arcmin. On all subjects, it was possible to measure TCA out to 12.5 degrees in the nasal, 10 degrees in the temporal, 12.5 degrees in the inferior, and 15 degrees in the superior visual field. The absolute amount of TCA between green and IR varied somewhat between subjects, but was approximately 4 arcmin at 10 degrees out in the nasal visual field. However, the increase in TCA was found to be linear with a slope close to 0.2 arcmin / degree of visual field angle for all subjects. Translating these results to the visual spectrum would yield a slightly higher slope and larger image shifts, which agree with the theoretical calculations by Thibos, J. Opt. Soc. Am. A, 1987.

    Conclusions: We have performed the first objective measurement of the TCA of the human eye across the central 30 degrees visual field. The 4 arcmin of TCA at 10 degrees off-axis is very similar to the resolution acuity of 0.5 to 0.7 logMAR at 10 degrees out in the nasal visual field (about 3 to 5 arcmin). Additionally, the measured cone-size at 10 degrees in the subjects of this study was about 1.4 - 1.7 arcmin, which means that the TCA blur covers around 2-3 cones. Therefore, the peripheral TCA can be visually significant.

  • 49.
    Winter, Simon
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Sabesan, Ramkumar
    Tiruveedhula, Pavan
    Privitera, Claudio
    Unsbo, Peter
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Roorda, Austin
    Transverse chromatic aberration across the visual field of the human eye2016In: Journal of Vision, ISSN 1534-7362, E-ISSN 1534-7362, Vol. 16, no 14, article id 9Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to measure the transverse chromatic aberration (TCA) across the visual field of the human eye objectively. TCA wasmeasured at horizontal and vertical field angles out to ±15° from foveal fixation in the right eye of four subjects. Interleaved retinal images were taken at wavelengths 543 nm and 842 nm in an adaptive optics scanning laser ophthalmoscope (AOSLO). To obtain true measures of the human eye's TCA, the contributions of the AOSLO system's TCA were measured using an on-axis aligned model eye and subtracted from the ocular data. The increase in TCA was found to be linear with eccentricity, with an average slope of 0.21 arcmin/degree of visual field angle (corresponding to 0.41 arcmin/degree for 430 nm to 770 nm). The absolute magnitude of ocular TCA varied between subjects, but was similar to the resolution acuity at 10° in the nasal visual field, encompassing three to four cones. Therefore, TCA can be visually significant. Furthermore, for high-resolution imaging applications, whether visualizing or stimulating cellular features in the retina, it is important to consider the lateral displacements between wavelengths and the variation in blur over the visual field.

  • 50.
    Wolffsohn, James S.
    et al.
    Aston Univ, Ophthalm Res Grp, Birmingham, W Midlands, England..
    Kollbaum, Pete S.
    Indiana Univ, Sch Optometry, Bloomington, IN USA..
    Berntsen, David A.
    Univ Houston, Coll Optometry, Ocular Surface Inst, Houston, TX USA..
    Atchison, David A.
    Queensland Univ Technol, Sch Optometry & Vis Sci, Inst Hlth & Biomed Innovat, Brisbane, Qld, Australia..
    Benavente, Alexandra
    SUNY Coll Optometry, New York, NY 10036 USA..
    Bradley, Arthur
    Indiana Univ, Sch Optometry, Bloomington, IN USA..
    Buckhurst, Hetal
    Plymouth Univ, Sch Hlth Profess, Peninsula Allied Hlth Ctr, Plymouth, Devon, England..
    Collins, Michael
    Queensland Univ Technol, Sch Optometry & Vis Sci, Inst Hlth & Biomed Innovat, Brisbane, Qld, Australia..
    Fujikado, Takashi
    Osaka Univ, Grad Sch Med, Dept Appl Visual Sci, Osaka, Japan..
    Hiraoka, Takahiro
    Univ Tsukuba, Dept Ophthalmol, Fac Med, Ibaraki, Japan..
    Hirota, Masakazu
    Osaka Univ, Grad Sch Med, Dept Appl Visual Sci, Osaka, Japan..
    Jones, Debbie
    Univ Waterloo, Sch Optometry & Vis Sci, Waterloo, ON, Canada..
    Logan, Nicola S.
    Aston Univ, Ophthalm Res Grp, Birmingham, W Midlands, England..
    Lundström, Linda
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Torii, Hidemasa
    Keio Univ, Sch Med, Dept Ophthalmol, Tokyo, Japan..
    Read, Scott A.
    Queensland Univ Technol, Sch Optometry & Vis Sci, Inst Hlth & Biomed Innovat, Brisbane, Qld, Australia..
    Naidoo, Kovin
    Univ KwaZulu Natal, African Vis Res Inst, Durban, South Africa..
    IMI - Clinical Myopia Control Trials and Instrumentation Report2019In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 60, no 3, p. M132-M160Article in journal (Refereed)
    Abstract [en]

    The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refractive error and/or axial length), secondary (patient reported outcomes and treatment compliance), and exploratory (peripheral refraction, accommodative changes, ocular alignment, pupil size, outdoor activity/lighting levels, anterior and posterior segment imaging, and tissue biomechanics). The currently available instrumentation, which the literature has shown to best achieve the primary and secondary outcomes, was reviewed and critiqued. Issues relating to study design and patient selection were also identified. These findings and consensus from the International Myopia Institute members led to final recommendations to inform future instrumentation development and to guide clinical trial protocols.

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