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  • 1.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    The 'light scattering factor'. Importance of stimulus geometry, contrast definition, and adaptation.1995In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 36, no 11, p. 2313-7Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Paulsson and Sjöstrand have suggested that the light scattering factor (LSF) can be estimated by using the equation: LSF = L/E (M2/M1-1). Here L is the space average luminance of the target, E is the illuminance of the glare source, and M2 and M1 are modulation contrast thresholds in the presence and absence of the glare source. To compensate for change of adaptation. Abrahamsson and Sjöstrand later modified the above equation by introducing a correction factor (CF): LSF = L/E ((CF) (M2/M1-1). The purpose of this study is to analyze the validity of the above equations.

    METHODS: The importance of stimulus geometry, contrast definition, background luminance, and glare illumination is studied through theoretical analysis and comparison with earlier studies. Stimulus geometry and contrast definition are studied through optical modeling. Adaptation is modeled according to the laws of Weber and DeVries-Rose.

    RESULTS: The choice of contrast definition may corrupt the result by a factor of 2. At background luminance levels above approximately 10 cd/m2, the Paulsson-Sjöstrand equation agrees well with theory. At lower background levels, the Abrahamsson-Sjöstrand equation is used with correction factors derived from adaptation measurements. Using this equation and earlier published data from glare testing performed at 2 cd/m2, the results are found to be in fair agreement with the light scattering theory.

    CONCLUSIONS: Glare testing using the Paulsson-Sjöstrand equation is found to be valid as long as the measurements are performed at high luminance levels (above 10 cd/m2), with targets of low spatiotemporal frequencies (e.g., 2 cpd and 1 Hz) and with the use of a properly chosen definition of contrast. At lower luminance levels, the Abrahamsson-Sjöstrand equation may be used with well-derived correction factors.

  • 2. Louwies, T.
    et al.
    Mekjavic, P. J.
    Cox, B.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Mekjavic, I. B.
    Kounalakis, S.
    De Boever, P.
    Separate and combined effects of hypoxia and horizontal bed rest on retinal blood vessel diameters2016In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 57, no 11, p. 4927-4932Article in journal (Refereed)
    Abstract [en]

    PURPOSE. To assess the separate and combined effects of exposure to prolonged and sustained recumbency (bed rest) and hypoxia on retinal microcirculation. METHODS. Eleven healthy male subjects (mean 6 SD age = 27 ± 6 years; body mass index [BMI] = 23.7 ± 3.0 kg m-2) participated in a repeated-measures crossover design study comprising three 21-day interventions: normoxic bed rest (NBR; partial pressure of inspired O2, PiO2 = 133.1 ± 0.3 mm Hg); hypoxic ambulation (HAMB; PiO2 = 90.0 6 0.4 mm Hg), and hypoxic bed rest (HBR; PiO2 = 90.0 ± 0.4 mm Hg). Central retinal arteriolar (CRAE) and venular (CRVE) equivalents were measured at baseline and at regular intervals during each 21- day intervention. RESULTS. Normoxic bed rest caused a progressive reduction in CRAE, with the change in CRAE relative to baseline being highest on day 15 (ΔDCRAE = -7.5 µm; 95% confidence interval [CI]: -10.8 to -4.2; P < 0.0001). Hypoxic ambulation resulted in a persistent 21-day increase in CRAE, reaching a maximum on day 4 (DCRAE = 9.4 µm; 95% CI: 6.0-12.7; P < 0.0001). During HBR, the increase in CRAE was highest on day 3 (ΔDCRAE = 4.5 µm; 95% CI: 1.2-7.8; P = 0.007), but CRAE returned to baseline levels thereafter. Central retinal venular equivalent decreased during NBR and increased during HAMB and HBR. The reduction in CRVE during NBR was highest on day 1 (ΔDCRVE = -7.9 µm; 95 CI: -13.3 to -2.5), and the maximum ΔDCRVE during HAMB (24.6 µm; 95% CI: 18.9-30.3) and HBR (15.2 µm; 95% CI: 9.8-20.5) was observed on days 10 and 3, respectively. CONCLUSIONS. The diameters of retinal blood vessels exhibited a dynamic response to hypoxia and bed rest, such that retinal vasodilation was smaller during combined bed rest and hypoxia than during hypoxic exposure.

  • 3.
    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)
  • 4.
    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)
  • 5. Michael, R.
    et al.
    Brismar, Hjalmar
    Lens growth and protein density in the rat lens after in vivo exposure to ultraviolet radiation2001In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 42, no 2, p. 402-408Article in journal (Refereed)
    Abstract [en]

    PURPOSE. To investigate lens growth after different doses of ultraviolet radiation (UVR) and to investigate the long-term effect of a near-threshold UVR dose on the refractive index distribution in the lens. METHODS. Sprague-Dawley rats received UVR (lambda (MAX) = 300 nm) unilaterally during a 15-minute period. The exposure dose ranged from 0.1 to 20 kJ/m(2), and the rats were kept for up to 32 weeks after exposure. Intact lenses were photographed and lens wet and dry masses were measured. The protein density was estimated by quantitative microradiography. Freeze-dried lens sections were used fur contact x-ray photographs. From the transmission of the microradiographs, protein density and refractive index profiles were calculated along the lens radius with a resolution of 2.5 mum. RESULTS. Lens dry mass in exposed eyes was lower than in nonexposed eyes at one week after exposure. Lens water content was decreased after low UVR doses but increased after high doses. The difference between exposed and nonexposed lenses in dry mass and water content increased with time after exposure. No significant difference was found for the mean protein density in exposed and nonexposed lenses. The protein density increased linearly in the lens cortex, from a minimum in the superficial cortex of 0.26 g/cm(3) to a maximum in the deep cortex of 0.81 g/cm(3). This corresponded to a refractive index of 1.38 and 1.48, respectively. CONCLUSIONS. Lenses exposed to UVR grew more slowly than their nonexposed contralaterals. This growth inhibition was dose dependent. Near-threshold doses led to decreased water content in the lens whereas high doses led to swelling. Six months: after near-threshold UVR exposure, no global change of the refractive index was found. However, local variations of the refractive index caused a subtle cortical light scattering.

  • 6.
    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)
  • 7. Reins, Rose Y.
    et al.
    Mesmar, Fahmi
    Williams, Cecilia
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    McDermott, Alison M.
    Microarray Analysis of Vitamin D Treated Human Corneal Epithelial Cells2016In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 57, no 12Article in journal (Refereed)
  • 8. Reins, Rose Y.
    et al.
    Mesmar, Fahmi
    Williams, Cecilia
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    McDermott, Alison M.
    Vitamin D Induces Global Gene Transcription in Human Corneal Epithelial Cells: Implications for Corneal Inflammation2016In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 57, no 6, p. 2689-2698Article in journal (Refereed)
    Abstract [en]

    PURPOSE. Our previous studies show that human corneal epithelial cells (HCEC) have a functional vitamin D receptor (VDR) and respond to vitamin D by dampening TLR-induced inflammation. Here, we further examined the timing of the cytokine response to combined vitamin D-TLR treatment and used genome-wide microarray analysis to examine the effect of vitamin D on corneal gene expression. METHODS. Telomerase-immortalized HCEC (hTCEpi) were stimulated with polyinosinicpolycytidylic acid (poly[I: C]) and 1,25-dihydroxyvitamin D-3 (1,25D(3)) for 2 to 24 hours and interleukin (IL)-8 expression was examined by quantitative (q) PCR and ELISA. Telomeraseimmortalized HCEC and SV40-HCEC were treated with 1,25D(3) and used in genome-wide microarray analysis. Expression of target genes was validated using qPCR in both cell lines and primary HCEC. For confirmation of IjBa protein, hTCEpi were treated with 1,25D(3) for 24 hours and cell lysates used in an ELISA. RESULTS. Treatment with 1,25D(3) increased poly(I: C)-induced IL-8 mRNA and protein expression after 2 to 6 hours. However, when cells were pretreated with 1,25D(3) for 24 hours, 1,25D(3) decreased cytokine expression. For microarray analysis, 308 genes were differentially expressed by 1,25D(3) treatment in hTCEpi, and 69 genes in SV40s. Quantitative (q) PCR confirmed the vitamin D-mediated upregulation of target genes, including nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (I kappa B alpha). In addition to increased transcript levels, I kappa B alpha protein was increased by 28% following 24 hours of vitamin D treatment. CONCLUSIONS. Microarray analysis demonstrates that vitamin D regulates numerous genes in HCEC and influences TLR signaling through upregulation of I kappa B alpha. These findings are important in dissecting the role of vitamin D at the ocular surface and highlight the need for further research into the functions of vitamin D and its influence on corneal gene expression.

  • 9.
    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.

  • 10.
    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.

  • 11.
    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)
  • 12.
    Unsbo, Peter
    et al.
    KTH.
    Lundstrom, L
    Gustafsson, J
    Finding a spectacle correction in keratoconus using a Hartmann-Shack sensor: a case study2004In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 45, p. U20-U20Article in journal (Other academic)
  • 13. 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.

  • 14.
    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)
  • 15. 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.

  • 16.
    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)
  • 17.
    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)
  • 18.
    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)
  • 19.
    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.

  • 20.
    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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