Hartmann–Shack wavefront sensors (HSWSs) are used in many disciplines to measure optical aberrations. Conventionally, the wavefront of interest is transferred onto the lenslet array of the HSWS with a telescopic 4f relay system. However, the 4f relay design restricts the choice of focal lengths and distances used for the relay system. In this paper, we describe a non-4f variant and demonstrate both theoretically and experimentally that its wavefront relaying properties equal that of a 4f system. We also present an alignment method for conjugating the wavefront with the lenslet array of the HSWS for both 4f and non-4f systems.

This study compares image quality on the peripheral retina for far and near vision in schoolchildren. Biometric data and simultaneous foveal and peripheral (±25^◦ horizontal field) wavefront data for two levels of accommodation (0.22 D and 5 D) were collected from 31 children aged 6 to 11 years. Relative peripheral refraction (RPR) was found to be larger and more negative in the nasal visual field than in the temporal. This difference increased with accommodation. Furthermore, correlations between image quality and biometric parameters were investigated. The results highlight the importance of peripheral image quality during near work for myopia research. The data presented also form the baseline measurements of the Stockholm Myopia Study, which is a longitudinal pilot study on ocular growth and peripheral image quality in schoolchildren in Stockholm, Sweden.

Purpose: Peripheral image quality is of high relevance to myopia research, yet peripheral refraction is difficult to define due to aberrations affecting the depth-of-focus. This study investigated the peripheral image quality (± 25° horizontal field) using three different image quality metrics, with added sphero-cylindrical wavefronts to find the best correction.

Methods: 19 adults (9 myopes, 10 emmetropes) and 33 children (5 myopes, 28 non-myopes) were measured using a dual angle wavefront aberrometer as part of the Stockholm Myopia Study. The optical image quality was calculated from the wavefronts, for 10,000 different sphero-cylindrical corrections around the 2^nd-order Zernike refraction, to find the best correction as well as the range of corrections with similar image quality (“depth-of-refraction”).

Results: Overall, peripheral best focus was not distinct, with a large depth-of-refraction. Emmetropes/non-myopes had larger peripheral depth-of-refraction than myopes (mean values of 2.69 D and 1.74 D, respectively (Strehl ratio metric)). For some subjects, this span of corrections was of a multifocal character. The prevalence of multifocality depended on the image quality metric but was generally more common in emmetropes/non-myopes than in myopes.

Conclusions: The peripheral visual field does not always have a clear best focus and can show multifocal properties in some individuals, with different corrections yielding similar image quality. As emmetropes/non-myopes had more multifocality and larger depth-of-refractionthan myopes, this indicates that inherent peripheral optical properties can play a role in myopia development.

Orthokeratology (ortho-k) is an effective method for slowing myopia progression, yet the control mechanism is not fully understood. In this study, changes in corneal aberrations and axial length during ortho-k treatment were investigated in 21 Scandinavian children over 18 months. Higher myopia at baseline was linked to larger corneal changes over 1 month of treatment in terms of total higher order aberrations root mean square error (RMS HOA, P < 0.0001) and 3rd order aberrations root mean square error (RMS 3^rd order, P < 0.001). Higher myopia at baseline was furthermore linked to better treatment effect over 18 months in terms of axial growth (P = 0.001), but the corneal changes over the same period were not directly linked to treatment effect (P > 0.05). The results suggest that the corneal higher order aberrations are related to the treatment mechanism of ortho-k, but that other aspects than RMS of the corneal reshaping are more relevant for regulating axialgrowth.

This study compares the effects on peripheral vision and image quality of four myopia control interventions: a) Perifocal spectacles/ArtOptica, b) Stellest spectacles/Essilor), c) MiyoSmart spectacles/Hoya and d) MiSight contact lenses/CooperVision. Five subjects participated with habitual or no correction as reference. Three techniques were used: 1) Hartmann-Shack sensors for wavefront errors, 2) double-pass imaging system for point-spread-functions (PSF), and 3) peripheral acuity evaluation. The results show that multiple evaluation methods are needed to fully quantify the optical effects of these myopia control interventions. Perifocal was found to make the relative peripheral refraction (RPR) more myopic in all subjects and to interact with the natural optical errors of the eye, hence showing larger variations in the effect on peripheral vision. MiSight had a smaller effect on RPR, but large effect on peripheral vision. Stellest and MiyoSmart also showed small effects on RPR but had broader double-pass PSFs for all participants, indicating reduced retinal contrast. Reduction in peripheral retinal contrast might thereby play a role in slowing myopia progression even when the peripheral refraction does not turn more myopic.

This study investigates relative peripheral refraction (RPR) in emmetropic and myopic eyes in the 25° nasal and temporal visual fields under far and near fixation, with control for any fluctuations in accommodation. Additional analysis of axial length and comparison with recently published eye models are also presented, constituting complementary adult data to the Stockholm Myopia Study. In the ten emmetropes, a pronounced nasal-temporal asymmetry was observed, with significantly more myopic RPR nasally and less myopic / more hyperopic RPR temporally at both accommodative states (p = 0.005). The nine myopes, in contrast, exhibited more symmetric peripheral profiles, with no significant nasal–temporal differences. Accommodation induced systematic shifts in both groups, producing increased relative myopia nasally and relative hyperopia temporally (p < 0.001). Axial length was significantly correlated with temporal hyperopic shifts during accommodation in myopes (p = 0.005), suggesting a structural contribution of ocular growth to peripheral optics. Comparison with eye models showed partial agreement, though experimental results revealed greater asymmetry than predicted in emmetropes and a weaker nasal–temporal distinction in myopes. Our findings indicate that variations in relative peripheral refraction over the horizontal visual field and with accommodation might be linked to ocular growth and are important for optical myopia control.