Utility of retinoscopy to examine peripheral refraction

Purpose: This study explored whether retinoscopy (RET) provides comparable results of relative peripheral refraction (RPR) to open–field autorefractometry (AR) in myopic subjects.Methods: Peripheral refraction was measured in 20 myopic and 20 control adult subjects. Both central and peripheral refraction (20° nasal and temporal eccentricity) were measured using RET and open-field AR. Differences in the median central spherical equivalent (SE), median RPR, and median J45/J180 power vectors between the RET and AR techniques were analyzed. Moreover, Bland – Altman plots were used to assess the agreement between RET and AR methods for RPR measurements in MG. Results: For MG, the median RPR values were positive (hyperopic shift), and no significant differences were observed between the RET and AR techniques with respect to RPR measurement. In addition, we did not observe any significant differences in the RPR values between the nasal and temporal eccentricities for either the RET or AR technique for myopic subjects. There was also a significant correlation and agreement between the RET and AR technique for RPR measurements. With respect to central refraction, the median SE was slightly more positive for the RET than for the AR technique. Inside the CG, we also found significant correlation between the RET and AR technique for RPR measurements, and we observed a myopic shift in peripheral eccentricities. Conclusion: Our results show that retinoscopy may be a useful tool for objective measurements of RPR in myopic subjects and may be used interchangeably with the open-field AR method in everyday clinical practice. (AU)

Anisomyopia and orthokeratology for myopia control - Axial elongation and relative peripheral refraction.

PURPOSE: To investigate axial elongation (AE) and changes in relative peripheral refraction (RPR) in anisomyopic children undergoing orthokeratology (ortho-k). METHODS: Bilateral anisomyopic children, 7-12 years of age, were treated with ortho-k. Axial length (AL) and RPR, from 30° nasal (N30°) to 30° temporal (T30°), were measured at baseline and every 6 months over the study period. AE, changes in RPR and changes in the interocular AL difference were determined over time. RESULTS: Twenty-six of the 33 subjects completed the 2-year study. The AE of the higher myopic (HM) eyes (at least 1.50 D more myopia than the other eye) (0.26 ± 0.29 mm) was significantly smaller than for the less myopic (LM) eyes (0.50 ± 0.27 mm; p = 0.003), leading to a reduction in the interocular difference in AL (p = 0.001). Baseline RPR measurements in the HM eyes were relatively more hyperopic at T30°, N20° and N30° (p ≤ 0.02) and greater myopic shifts were observed at T20° (p < 0.001), T30° (p < 0.001), N20° (p = 0.02) and N30° (p = 0.01) after lens wear. After 2 years of ortho-k lens wear, temporal-nasal asymmetry increased significantly, being more myopic at the temporal locations in both eyes (p < 0.001), while AE was associated with the change in RPR at N20° (ß = 0.134, p = 0.01). The interocular difference in AE was also positively associated with the interocular difference in RPR change at N30° (ß = 0.111, p = 0.02). CONCLUSIONS: Ortho-k slowed AE in bilateral anisomyopia, with slower growth in the HM eyes leading to a reduction in interocular AL differences. After ortho-k, RPR changed from hyperopia to myopia, with greater changes induced in the HM eyes, and slower AE was associated with a more myopic shift in RPR, especially in the nasal field of both eyes.

Enhancement of the Inner Foveal Response of Young Adults with Extended-Depth-of-Focus Contact Lens for Myopia Management.

BACKGROUND: Myopia management contact lenses have been shown to successfully decrease the rate of eye elongation in children by changing the peripheral refractive profile of the retina. Despite the efforts of the scientific community, the retinal response mechanism to defocus is still unknown. The purpose of this study was to evaluate the local electrophysiological response of the retina with a myopia control contact lens (CL) compared to a single-vision CL of the same material. METHODS: The retinal electrical activity and peripheral refraction of 16 eyes (16 subjects, 27.5 ± 5.7 years, 13 females and 3 males) with myopia between -0.75 D and -6.00 D (astigmatism < 1.00 D) were assessed with two CLs (Filcon 5B): a single-vision (SV) CL and an extended-depth-of-focus (EDOF) CL used for myopia management. The peripheral refraction was assessed with an open-field WAM-5500 auto-refractometer/keratometer in four meridians separated by 45° at 2.50 m distance. The global-flash multifocal electroretinogram (gf-mfERG) was recorded with the Reti-port/scan21 (Roland Consult) using a stimulus of 61 hexagons. The implicit time (in milliseconds) and response density (RD, in nV/deg2) of the direct (DC) and induced (IC) components were used for comparison between lenses in physiological pupil conditions. RESULTS: Although the EDOF decreased both the HCVA and the LCVA (one and two lines, respectively; p < 0.003), it still allowed a good VA. The EDOF lens induced a myopic shift in most retinal areas, with a higher and statistically significant effect on the nasal retina. No differences in the implicit times of the DC and IC components were observed between SV and EDOF. Compared with the SV, the EDOF lens showed a higher RD in the IC component in the foveal region (p = 0.032). In the remaining retinal areas, the EDOF evoked lower, non-statistically significant RD in both the DC and IC components. CONCLUSIONS: The EDOF myopia control CL enhanced the response of the inner layers of the fovea. This might suggest that, besides other mechanisms potentially involved, the central foveal retinal activity might be involved in the mechanism of myopia control with these lenses.

Peripheral Eye Length Evaluation in Myopic Children Undergoing Orthokeratology Treatment for 12 Months Using MRI.

Purpose: To investigate changes in peripheral eye length (PEL) in myopic children undergoing orthokeratology (Ortho-K) treatment for 12 months using MRI. The results were compared to single vision spectacle wearers (SVS). Patients and Methods: A total of 70 children with myopia (aged 8-9 years old) were recruited. A total of 45 children were fitted with Ortho-K, and 25 were fitted with SVS. The PEL and axial length (AL) were measured by using MRI 3-Tesla, whereas central and peripheral refraction (PR) measurements were conducted at ±30 degrees horizontally with nasal (N) and temporal (T) intervals of 10°, 20°, and 30° and with an open field autorefractometer (WAM-5500 Grand Seiko). All the measurements were conducted at the baseline and 12 months. Results: The MRI analysis indicates that at 12 months, the SVS group showed more elongation of the PEL and AL at all eccentricities than the Ortho-K group did (p < 0.05). The Ortho-K group only showed significant PEL elongation beyond 20 degrees at N20, N30, T20, and T30 (p < 0.05); however, a significant reduction in the AL was detected in the center AL, N10, and T10 (p < 0.05). All eccentricities in the relative PR of the Ortho-K group were significantly more myopic than at the baseline (p < 0.05), whereas in the SVS group, all eccentricities in the relative PR were shown to be significantly more hyperopic than at the baseline (p < 0.05). The PEL and PR showed negative correlations at 12 months in the Ortho-K group. Conclusion: MRI analysis can be utilized to describe changes in PEL in myopic children. It appears that as myopia progressed in Ortho-K lens wearers, the PEL increased by a greater amount than the AL did; thus, the retina was reshaped to become increasingly oblate and to display peripheral myopic defocus.

One-year results for myopia control of orthokeratology with different back optic zone diameters: a randomized trial using a novel multispectral-based topographer.

AIM: To present the 1-year results of a prospective cohort study investigating the efficacy, potential mechanism, and safety of orthokeratology (ortho-k) with different back optic zone diameters (BOZD) for myopia control in children. METHODS: This randomized clinical study was performed between Dec. 2020 and Dec. 2021. Participants were randomly assigned to three groups wearing ortho-k: 5 mm BOZD (5-MM group), 5.5 mm BOZD (5.5-MM group), and 6 mm BOZD (6-MM group). The 1-year data were recorded, including axial length, relative peripheral refraction (RPR, measured by multispectral refractive topography, MRT), and visual quality. The contrast sensitivity (CS) was evaluated by CSV-1000 instrument with spatial frequencies of 3, 6, 12, and 18 cycles/degree (c/d); the corneal higher-order aberrations (HOAs) were measured by iTrace aberration analyzer. The one-way ANOVA was performed to assess the differences between the three groups. The correlation between the change in AL and RPR was calculated by Pearson's correlation coefficient. RESULTS: The 1-year results of 20, 21, and 21 subjects in the 5-MM, 5.5-MM, and 6-MM groups, respectively, were presented. There were no statistical differences in baseline age, sex, or ocular parameters between the three groups (all P>0.05). At the 1-year visit, the 5-MM group had lower axial elongation than the 6-MM group (0.07±0.09 vs 0.18±0.11 mm, P=0.001). The 5-MM group had more myopic total RPR (TRPR, P=0.014), with RPR in the 15°-30° (RPR 15-30, P=0.015), 30°-45° (RPR 30-45, P=0.011), temporal (RPR-T, P=0.008), and nasal area (RPR-N, P<0.001) than the 6-MM group. RPR 15-30 in the 5.5-MM group was more myopic than that in the 6-MM group (P=0.002), and RPR-N in the 5-MM group was more myopic than that in the 5.5-MM group (P<0.001). There were positive correlations between the axial elongation and the change in TRPR (r=0.756, P<0.001), RPR 15-30 (r=0.364, P=0.004), RPR 30-45 (r=0.306, P=0.016), and RPR-N (r=0.253, P=0.047). The CS decreased at 3 c/d (P<0.001), and the corneal HOAs increased in the 5-MM group (P=0.030). CONCLUSION: Ortho-k with 5 mm BOZD can control myopia progression more effectively. The mechanism may be associated with greater myopic shifts in RPR.

Orthokeratology combined with spectacles in moderate to high myopia adolescents.

PURPOSE: Wearing ortho-k lenses overnight may not fully correct their daytime refractory errors of adolescents with moderate to high myopia. There are three common ways to deal with the daytime residual refractive error (RRE): 1) wearing spectacles to correct the RRE; 2) wear ortho-k lenses during the daytime instead of overnight.; 3) not correcting the residual refractive error. According to previous laboratory studies, myopic peripheral refraction is associated with better myopic control. This study had two aims:1) to compare relative peripheral refractive error (RPRE) among these ways after one-month stabilization; 2) to assess the axial length changes over 2 years of ortho-k lens overnight wear combined with spectacle glasses. METHODS: This was a prospective, non-controlled, non-randomized, observational study in which a total of 27 subjects (20 females, 7 males, mean age 12.48 ± 2.23Y) with spherical equivalent refractive error from -5.00 to -8.25D were enrolled. All participants in the study wore orthokeratology (ortho-k) lenses overnight for a minimum of one month. Subsequently, their peripheral refractive error (PRE) was assessed using an open-field autorefractor. During the assessment, the participants underwent three conditions in a random order in a same morning: 1) unaided eye after orthokeratology (referred to as the Unaided-eye condition), 2) wearing glasses to correct any remaining refractive errors after orthokeratology (referred to as the Spec-RE condition), and 3) wearing ortho-k lenses during the daytime (referred to as the Continuous OK wear condition). After testing, all subjects were instructed to wear ortho-k lenses overnight and glasses during the daytime to correct their RRE for the next 2 years, during which time the progression of their axial length was followed up. RESULTS: 1) RPRE in either Unaided-eye or Spec-RE condition subjects were significantly more myopic than those in the Continuous OK wear condition. 2) No difference in RPRE was seen between Unaided-eye and Spec-RE conditions. 3) Axial length growth was 0.05 ± 0.20 mm and 0.17 ± 0.32 mm (mean ± standard deviation) at 1-year and 2-year follow-ups after the initial visit, respectively, which were comparable to mild myopia patients after orthokeratology. 4) After orthokeratology, axial length change had negative correlation with the initial age (p = 0.001, r = -0.616) and residual diopter (p = 0.022). CONCLUSIONS: For myopes above refraction < -5.00D, wearing Ortho-k lenses overnight and glasses to correct the RRE in the daytime is recommended to ensure good visual quality and have more myopic RPRE for potential myopia control.

Utility of retinoscopy to examine peripheral refraction.

PURPOSE: This study explored whether retinoscopy (RET) provides comparable results of relative peripheral refraction (RPR) to open-field autorefractometry (AR) in myopic subjects. METHODS: Peripheral refraction was measured in 20 myopic and 20 control adult subjects. Both central and peripheral refraction (20° nasal and temporal eccentricity) were measured using RET and open-field AR. Differences in the median central spherical equivalent (SE), median RPR, and median J45/J180 power vectors between the RET and AR techniques were analyzed. Moreover, Bland - Altman plots were used to assess the agreement between RET and AR methods for RPR measurements in MG. RESULTS: For MG, the median RPR values were positive (hyperopic shift), and no significant differences were observed between the RET and AR techniques with respect to RPR measurement. In addition, we did not observe any significant differences in the RPR values between the nasal and temporal eccentricities for either the RET or AR technique for myopic subjects. There was also a significant correlation and agreement between the RET and AR technique for RPR measurements. With respect to central refraction, the median SE was slightly more positive for the RET than for the AR technique. Inside the CG, we also found significant correlation between the RET and AR technique for RPR measurements, and we observed a myopic shift in peripheral eccentricities. CONCLUSION: Our results show that retinoscopy may be a useful tool for objective measurements of RPR in myopic subjects and may be used interchangeably with the open-field AR method in everyday clinical practice.

Peripheral refraction under different levels of illuminance.

Peripheral refraction is believed to be involved in the development of myopia. The aim of this study was to compare the relative peripheral refraction (RPR) at four different levels of illuminance, ranging from photopic conditions to complete darkness, using an open-field autorefraction method. The RPR was calculated for each eccentricity by subtracting central from peripheral autorefraction measurements. The study included 114 myopic eyes from 114 subjects (mean age of 21.81 ± 1.91 years) and the mean difference in RPR between scotopic and photopic conditions (0 and 300 lux, respectively) was +0.32 D at 30° temporal and +0.37 D at 30° in the nasal visual field (NVF). Statistically significant differences were observed between 0 and 300 lux at 30° in the temporal visual field and at 30° and 20° in the NVF. Our results revealed a significant increase in relative peripheral hyperopia with increasing visual field eccentricity along the horizontal visual field in myopic eyes of young adults. Furthermore, this relative peripheral hyperopia increased as illumination decreased. These findings suggest that an increase in peripheral illuminance may protect against myopic eye growth.

Advances in peripheral defocus and myopia prevention and control / 国际眼科杂志(Guoji Yanke Zazhi)

The global prevalence of myopia is increasing year by year, leading to many ocular health issues and social problems. In recent years, it has been confirmed that peripheral defocus is closely related to the occurrence and development of myopia. Alteration of the state of peripheral defocus can significantly influence the progression of myopia and emmetropization, but the exact mechanisms are still unclear. At present, there is no method that can completely control myopia. Nowadays, the main controlling methods, including orthokeratology lens, peripheral defocus lens and multi-focal soft lens, have been confirmed to be closely related to peripheral defocus. In this paper, we will review and summarize the development and effect of these peripheral defocus relating control methods. In addition, the researches on the related mechanisms of peripheral retinal defocus and myopia prevention and control at home and abroad are reviewed, as well as the potential mechanisms of peripheral defocus, with a view to further improving the controlling effects of existing methods, developing new prevention and control methods and reducing the incidence and progression of myopia.

Observation of peripheral refraction in myopic anisometropia in young adults.

AIM: To investigate the differences in retinal refraction difference values (RDVs) of adult patients with myopic anisometropia compared with those without myopic anisometropia, and to investigate the relationship between ocular biometric measurements and relative peripheral refraction. METHODS: This clinical observation study included 130 patients with myopia (-0.25 to -10.00 D) between October 2022 and January 2023 aged between 18 and 40y. The patients were divided into anisometropia (n=63; difference in binocular anisometropia ≥1.00 D) and non-anisometropia (n=67; difference in binocular anisometropia <1.00 D) groups accordingly. Ocular biometric measurements were performed by optical biometrics and corneal topography to assess the steep keratometry (Ks), flap keratometry (Kf), axial length (AL), corneal astigmatism (CYL; Ks-Kf), surface regularity index (SRI), surface asymmetry index (SAI), and central corneal thickness (CCT). The RDV was measured at five retinal areas from the fovea to 53 degrees (RDV-0-10, RDV-10-20, RDV-20-30, RDV-30-40, and RDV-40-53), the total RDV (TRDV) of 53 degrees, and four regions, including RDV-superior, RDV-inferior, RDV-temporal, and RDV-nasal. An analysis of Spearman correlation was carried out to examine the correlation between RDV and the spherical equivalent (SE) and ocular biological parameters. RESULTS: Within RDV-20-53, both groups showed relative hyperopic defocus, and the increase in RDV corresponds to the increase in eccentricity. In the myopic anisometropia group, the TRDV, RDV-20-53, RDV-superior, and more myopic eyes had significantly higher RDV-temporal values than less myopic eyes. (P<0.05). In the non-anisometropia group, there was no significant difference in the RDV between the more and less myopic eyes at different eccentricities (P>0.05). There was a negative correlation between SE and TRDV (r=-0.205, P=0.001), RDV-20-53 (r=-0.281, -0.183, -0.176, P<0.05), RDV-superior (r=-0.251, P<0.001), and RDV-temporal (r=-0.230, P<0.001), a negative correlation between CYL and RDV-10-30 (r=-0.147, -0.180, P<0.05), and a negative correlation between SRI and RDV-0-20 (r=-0.190, -0.170, P<0.05). AL had a positive correlation with RDV-20-30 (r=0.164, P=0.008) and RDV-temporal (r=0.160, P=0.010). CONCLUSION: More myopic eyes in patients with myopic anisometropia show more peripheral hyperopic defocus. Diopter and corneal morphology may affect peripheral retinal defocus.

One-year results for myopia control with aspheric base curve orthokeratology lenses: A prospective randomised clinical trial.

PURPOSE: To compare the effect of orthokeratology (ortho-k) using aspheric or spherical base curve (BCA vs. BCS) contact lenses on axial elongation and the relative peripheral refraction change (RPRC) in Chinese children. METHODS: Children aged 8-12 years with myopia between -0.75 and -4.00 D and astigmatism ≤1.00 D were randomly assigned to the BCA or BCS group. Peripheral refraction was assessed at 10°, 20° and 30° along the temporal and nasal retina at baseline and at the 12-month visit. Axial length (AL) was measured under cycloplegia at baseline and at the 6- and 12-month visits. Only right eye data were analysed. Repeated-measures analysis of covariance was performed to examine the differences in axial elongation and the RPRC between the BCA and BCS groups. RESULTS: The 1-year results from 31 BCA and 32 BCS subjects were analysed. No significant between-group differences were found at baseline (p ≥ 0.28). At the 12-month visit, the BCA lens produced a greater absolute RPRC along the horizontal meridian than the BCS lens (p < 0.001). Axial elongation was slower in the BCA group (0.19 ± 0.20 mm) than in the BCS group (0.29 ± 0.14 mm; p = 0.03). Axial elongation was correlated with the RPRC at 10° (r = 0.43, p = 0.02) and 20° (r = 0.39, p = 0.03) along the temporal retina in the BCA group; however, these correlations were not observed in the BCS group. CONCLUSION: The BCA ortho-k lens could improve the efficacy of slowing axial elongation in children. The improved myopia control observed in the BCA group may be the result of a larger myopic shift in relative peripheral refraction within 20° along the temporal retina.

Relative peripheral hyperopia leads to greater short-term axial length growth in White children with myopia.

PURPOSE: Controversy exists regarding the influence of peripheral visual experience on the onset and progression of childhood myopia. This longitudinal, observational study evaluated the relationship between relative peripheral refraction (RPR) and changes in refractive error and axial length (AL) over 12 months in White children aged 6-7 and 12-13 years with a range of baseline refractive errors. METHODS: Cycloplegic baseline autorefraction at horizontal retinal eccentricities of 0° and ±30° were recorded with the Shin-Nippon NVision-K 5001 while AL was measured using the Zeiss IOLMaster 700. Measurements were repeated after 12 months on a subgroup. Refractive data were transposed into power vectors as mean spherical equivalent (M), J0 and J45 . RPR was calculated by subtracting central from peripheral measurements. Participants were defined as myopic (M ≤ -0.50 D), premyopic (-0.50 D < M ≤ +0.75 D), emmetropic (+0.75 D < M < +2.00 D) or hyperopic (M ≥ +2.00 D). RESULTS: Data were collected from 222 and 245 participants aged 6-7 and 12-13 years, respectively. Myopic eyes demonstrated, on average, more hyperopic RPR. Emmetropes and premyopes displayed emmetropic RPR, and hyperopes showed a myopic RPR. Fifty-six 6- to 7-year-olds and seventy 12- to 13-year-olds contributed 12-month repeated measures. Longitudinal data demonstrated a significant relationship between a more hyperopic RPR in the nasal retina and greater short-term axial elongation in teens with myopia at baseline (ß = 0.69; p = 0.04). Each dioptre of relative peripheral hyperopia in the nasal retina was associated with an additional 0.10 mm (95% CI: 0.02-0.18 mm) annual increase in AL. CONCLUSIONS: Hyperopic RPR in the nasal retina of myopic children is indicative of increased risk for rapid axial elongation and may be a useful metric to support decision-making in myopia management.

Association between relative peripheral refraction and corresponding electro-retinal signals.

PURPOSE: Considering the potential role of the peripheral retina in refractive development and given that peripheral refraction varies significantly with increasing eccentricity from the fovea, we investigated the association between relative peripheral refraction (RPR) and corresponding relative peripheral multifocal electroretinogram (mfERG) responses (electro-retinal signals) from the central to the peripheral retina in young adults. METHODS: Central and peripheral refraction using an open-field autorefractor and mfERG responses using an electrophysiology stimulator were recorded from the right eyes of 17 non-myopes and 24 myopes aged 20-27 years. The relative mfERG N1, P1 and N2 components (amplitude density and implicit time) of a mfERG waveform were compared with the corresponding RPR measurements at the best-matched eccentricities along the principal meridians, that is at the fovea (0°), horizontal (±5°, ±10° and ± 25°) and vertical meridians (±10° and ± 15°). RESULTS: The mean absolute mfERG N1, P1 and N2 amplitude densities (nV/deg2 ) were maximum at the fovea in both non-myopes (N1: 57.29 ± 14.70 nV/deg2 , P1: 106.29 ± 24.46 nV/deg2 , N2: 116.41 ± 27.96 nV/deg2 ) and myopes (N1: 56.25 ± 15.79 nV/deg2 , P1: 100.79 ± 30.81 nV/deg2 , N2: 105.75 ± 37.91 nV/deg2 ), which significantly reduced with increasing retinal eccentricity (p < 0.01). No significant association was reported between the RPR and corresponding relative mfERG amplitudes at each retinal eccentricity (overall Pearson's correlation, r = -0.25 to 0.26, p ≥ 0.09). In addition, the presence of relative peripheral myopia or hyperopia at extreme peripheral retinal eccentricities did not differentially influence the corresponding relative peripheral mfERG amplitudes (p ≥ 0.24). CONCLUSIONS: Relative peripheral mfERG signals are not associated with corresponding RPR in young adults. It is plausible that the electro-retinal signals may respond to the presence of absolute hyperopia (and not relative peripheral hyperopia), which requires further investigation.

Peripheral Refraction and Visual Function of Novel Perifocal Ophthalmic Lens for the Control of Myopia Progression.

This study aimed to evaluate the peripheral defocus induced with a novel perifocal ophthalmic lens for myopia progression control and the potential impact on visual function. This experimental, non-dispensing crossover study evaluated 17 myopic young adults. The peripheral refraction was measured using an open-field autorefractor, at 2.50 m from the target point, in two eccentric points, 25° temporal, 25° nasal, and central vision. Visual contrast sensitivity (VCS) was measured at 3.00 m with a Vistech system VCTS 6500 in low light conditions. Light disturbance (LD) was assessed with a light distortion analyzer 2.00 m away from the device. Peripheral refraction, VCS, and LD were assessed with a monofocal lens and perifocal lens (with an add power of +2.50 D on the temporal side of the lens, and +2.00 D on the nasal side). The results showed that the perifocal lenses induced an average myopic defocus of -0.42 ± 0.38 D (p-value < 0.001) in the nasal retina, at 25° The changes induced by the lower add power in the nasal part of the lens did not induce statistically significant changes in the refraction of the temporal retina. The VCS and LD showed no significant differences between the monofocal and perifocal lenses.

Technical notes on peripheral refraction, peripheral eye length and retinal shape determination.

PURPOSE: To give an overview of the misconceptions and potential artefacts associated with measuring peripheral refractive error and eye length, the use of these measures to determine the retinal shape and their links to myopia development. Several issues were identified: the relationship between peripheral refractive error and myopia development, inferring the retinal shape from peripheral refraction or eye length patterns, artefacts and accuracy when measuring peripheral eye length using an optical biometer. METHODS: A theory was developed to investigate the influence of artefacts in measuring peripheral eye length and on using peripheral eye length to make inferences about retinal shape. RESULTS: When determining peripheral axial length, disregarding the need to realign instruments with mounted targets can lead to incorrect field angles and positions of mounted targets by more than 10% for targets placed close to the eye. Peripheral eye length is not a good indicator of the effects of myopia or of treatment for myopia development because eyes of different lengths but with the same retinal shape would be interpreted as having different retinal shapes; the measurement leads to overestimates of changes in retinal curvature as myopia increases. Determining peripheral eye length as a function of estimated retinal height rather than field angle will halve the magnitude of the artefact. The artefact resulting from the peripheral use of biometers with an on-axis calibration is modest and can be ignored. CONCLUSION: There are significant issues with peripheral measurements of the refractive error and eye length that must be considered when interpreting these data for myopia research. Some of these issues can be mitigated, while others require further investigation.

Peripheral Refraction of Two Myopia Control Contact Lens Models in a Young Myopic Population.

Peripheral refraction can lead to the development of myopia. The aim of this study was to compare relative peripheral refraction (RPR) in the same cohort of uncorrected (WCL) and corrected eyes with two different soft contact lenses (CL) designed for myopia control, and to analyze RPR depending on the patient's refraction. A total of 228 myopic eyes (114 healthy adult subjects) (−0.25 D to −10.00 D) were included. Open-field autorefraction was used to measure on- and off- axis refractions when uncorrected and corrected with the two CLs (dual focus (DF) and extended depth of focus (EDOF)). The RPR was measured every 10° out to 30° in a temporal-nasal orientation and analyzed as a component of the power vector (M). The average RPR for all subjects was hyperopic when WCL and when corrected with EDOF CL design, but changed to a myopic RPR when corrected with DF design. Significant differences were found between RPR curves with both CLs in all the eccentricities (Bonferroni correction p < 0.008, except 10°N). An incremental relationship between relative peripheral refraction at 30 degrees and myopia level was found. It is concluded that the two CLs work differently at the periphery in order to achieve myopia control.

The effects of base curve aspheric orthokeratology lenses on corneal topography and peripheral refraction: A randomized prospective trial.

BACKGROUND: To investigate the effects of orthokeratology (ortho-k) lenses with aspheric and spherical base curve designs on corneal refractive power (CRP) and peripheral refraction. METHODS: Children aged 8 to 12 years with myopia between -0.75 D to -4.00 D, astigmatism ≤1.00 D, and corneal astigmatism ≤1.50 D were randomly assigned to the base curve aspheric (BCA) and base curve spherical (BCS) ortho-k lens groups. CRP was assessed for the central 8 mm cornea along horizontal and vertical meridians, and peripheral refraction was measured at 10°, 20°, and 30° along the nasal and temporal retina. Primary measurements included relative corneal refractive power change (RCRPC) and relative peripheral refraction change (RPRC). RESULTS: The 3-month results of the 33 and 29 subjects (right eye only) in the BCA and BCS groups, respectively, were obtained. Nonsignificant differences were found in the baseline data between the two groups (p > 0.05). At the 3-month follow-up visit, the mean RCRPC in the BCA group (2.08 ± 0.65 D) was significantly greater than that in the BCS group (1.32 ± 0.81 D) (F1,51 = 25.25, p < 0.001). The BCA group (-1.82 ± 0.65 D) exhibited a larger absolute RPRC than the BCS group (-0.98 ± 0.54 D) (F1,57 = 33.73, p < 0.001). CONCLUSIONS: It was found that the BCA ortho-k lens resulted in a more aspheric treatment zone and a more myopic relative peripheral refraction (RPR) along the horizontal meridian. The more myopic RPR was contributed by a more hyperopic central refraction and a more myopic peripheral refraction in the BCA group.

Comparison of an open view autorefractor with an open view aberrometer in determining peripheral refraction in children

Purpose: The aim of this study was to compare central and peripheral refraction using an open view Shin-Nippon NVision-K 5001 autorefractor and an open view COAS-HD VR aberrometer in young children.MethodsCycloplegic central and peripheral autorefraction was measured in the right eye of 123 children aged 8 to 16 years. Three measurements each were obtained with both Shin-Nippon NVision-K 5001 autorefractor and COAS-HD VR aberrometer along the horizontal visual field up to 30° (nasal and temporal) in 10° steps. The refraction from the autorefractor was compared with aberrometer refraction for pupil analysis diameters of 2.5-mm and 5.0-mm.ResultsThe Shin-Nippon was 0.30 D more hyperopic than COAS-HD VR at 2.5-mm pupil and 0.50 D more hyperopic than COAS-HD VR at 5-mm pupil for central refraction. For both pupil sizes, the 95% limits of agreement were approximately 0.50 D for central refraction, and limits were wider in the nasal visual field compared to the temporal visual field. The mean difference for both J0 and J45 were within 0.15 D and the 95% limits of agreement within 0.90 D across the horizontal visual field.ConclusionDefocus components were similar between the Shin-Nippon autorefractor and the COAS-HD VR aberrometer with a 2.5-mm pupil for most visual field angles. However, there was a significant difference in defocus component between the Shin-Nippon autorefractor and the COAS-HD VR aberrometer with a 5.0-mm pupil, wherein the autorefractor measured more hyperopia. The astigmatic components J0 and J45 were similar between instruments for both central and peripheral refraction. (AU)

Comparison of an open view autorefractor with an open view aberrometer in determining peripheral refraction in children.

PURPOSE: The aim of this study was to compare central and peripheral refraction using an open view Shin-Nippon NVision-K 5001 autorefractor and an open view COAS-HD VR aberrometer in young children. METHODS: Cycloplegic central and peripheral autorefraction was measured in the right eye of 123 children aged 8 to 16 years. Three measurements each were obtained with both Shin-Nippon NVision-K 5001 autorefractor and COAS-HD VR aberrometer along the horizontal visual field up to 30° (nasal and temporal) in 10° steps. The refraction from the autorefractor was compared with aberrometer refraction for pupil analysis diameters of 2.5-mm and 5.0-mm. RESULTS: The Shin-Nippon was 0.30 D more hyperopic than COAS-HD VR at 2.5-mm pupil and 0.50 D more hyperopic than COAS-HD VR at 5-mm pupil for central refraction. For both pupil sizes, the 95% limits of agreement were approximately 0.50 D for central refraction, and limits were wider in the nasal visual field compared to the temporal visual field. The mean difference for both J0 and J45 were within 0.15 D and the 95% limits of agreement within 0.90 D across the horizontal visual field. CONCLUSION: Defocus components were similar between the Shin-Nippon autorefractor and the COAS-HD VR aberrometer with a 2.5-mm pupil for most visual field angles. However, there was a significant difference in defocus component between the Shin-Nippon autorefractor and the COAS-HD VR aberrometer with a 5.0-mm pupil, wherein the autorefractor measured more hyperopia. The astigmatic components J0 and J45 were similar between instruments for both central and peripheral refraction.

Relative peripheral refraction in myopic children wearing orthokeratology lenses using a novel multispectral refraction topographer.

CLINICAL RELEVANCE: Orthokeratology (OK) lens is commonly used to control myopia progression of children. Understanding the relationship between relative peripheral refraction (RPR) and the growth rate of axial length (AL) may assist in explaining myopic progression. BACKGROUND: The aim of this work is to investigate the RPR in myopic children wearing OK lenses, and to evaluate its relationship with the growth rate of AL. METHODS: RPRs of 31 children wearing OK lenses and 31 children wearing single-vision glasses were measured with multispectral refraction topography (MRT). MRT shows the total RPR (TRPR), RPR in the superior area (RPR-S), RPR in the inferior area (RPR-I), RPR in the temporal area (RPR-T) and RPR in the nasal area (RPR-N), respectively. It also shows RPR in the visual field of 15° (RPR-15), 30° (RPR-30) and 45° (RPR-45), respectively. RPRs in the visual field from 15° to 30°, 30° to 45° and 15° to 45° are recorded as RPR-(30-15), RPR-(45-30) and RPR-(45-15), respectively. According to the growth rate of AL, children wearing OK lenses were further divided into slow and fast growth groups. RESULTS: TRPR, RPR-I, RPR-T, RPR-N, RPR-15, RPR-30, RPR-45, RPR-(30-15), RPR-(45-30), and RPR-(45-15) of children in the OK lens group were significantly smaller than in the control group (all P < 0.05). TRPR, RPR-N, RPR-15, RPR-30, RPR-45, RPR-(30-15), and RPR-(45-15) of the slow growth group were significantly smaller than in the fast growth group (all P < 0.05). The growth rate of AL were positively correlated with TRPR (R = 0.383, P = 0.040), RPR-N (R = 0.395, P = 0.034), RPR-30 (R = 0.408, P = 0.028), RPR-45 (R = 0.377, P = 0.044), RPR-(30-15) (R = 0.390, P = 0.036). CONCLUSIONS: RPRs of children show relative myopic defocus after wearing OK lenses. Furthermore, the growth rate of AL is smaller with more negative RPR.