Analysis of the peripheral refraction in myopic adults using a novel multispectral refraction topography.

Purpose: To determine the distribution and characteristics of peripheral refraction in adults with myopia using the novel multispectral refraction topography. Method: A total of 187 adults with myopia were recruited for this study. This study was conducted in two stages. Part I: participants were divided into 6 groups based on the central refraction of the right eyes, Part II: according to the interocular differences in refractive error (IOD) of the central refraction, we divided the participants into isomyopia group (IOD<1.00 D) and anisomyopia group (IOD≥1.0 D). We surveyed the characteristics of peripheral refraction and relative peripheral refraction (RPR), as well as the correlation between RPR and central refraction, age, sex, and axial length. Result: Part I: With an increase in the degree of myopia, relative peripheral hyperopia developed from the center to the periphery. A statistically significant hyperopia shift compared to the center (P < 0.05) was first observed on the temporal side within a 40° field of view at the posterior pole of the retina. The RPR of the temporal, superior, and inferior retinas positively correlated only with age. Part II: In the isomyopic participants, there was no difference in peripheral refraction between the eyes (P < 0.05). In the anisomyopic participants, the RPR of the more myopic eyes was more hyperopic than that of the less myopic eyes in NRDV40-50, SRDV10-20, SRDV30-50, TRDV20-30, TRDV40-50, and IRDV10-40. Conclusion: With an increase in the degree of myopia, relative peripheral hyperopia developed from the center to the periphery, and peripheral refraction progressed at different rates in various retinal zones.

Relative peripheral refraction in school children with different refractive errors using a novel multispectral refraction topographer.

AIM: To compare relative peripheral refraction (RPR) in Chinese school children with different refractive errors using multispectral refraction topography (MRT). METHODS: A total of 713 eyes of primary school children [172 emmetropia (E), 429 low myopia (LM), 80 moderate myopia (MM), and 32 low hypermetropia (LH)] aged 10 to 13y were analyzed. RPRs were measured using MRT without mydriasis. MRT results showed RPR at 0-15° (RPR 0-15), 15°-30° (RPR 15-30), and 30°-45° (RPR 30-45) annular in the inferior (RPR-I), superior (RPR-S), nasal (RPR-N), and temporal (RPR-T) quadrants. Spherical equivalent (SE) was detected and calculated using an autorefractor. RESULTS: There were significant differences of RPR 15-30 between groups MM [0.02 (-0.12; 0.18)] and LH [-0.13 (-0.36; 0.12)] (P<0.05), MM and E [-0.06 (-0.20; 0.10)] (P<0.05), and LM [-0.02 (-0.15; 0.15)] and E (P<0.05). There were also significant differences of RPR 30-45 between groups MM [0.45 (0.18; 0.74)] and E [0.29 (-0.09; 0.67)] (P<0.05), and LM [0.44 (0.14; 0.76)] and E (P<0.001). RPR values increased from the hyperopic to medium myopic group in each annular. There were significant differences of RPR-S between groups MM [-0.02 (-0.60; 0.30)] and E [-0.44 (-0.89; -0.04)] (P<0.001), and LM [-0.28 (-0.71; 0.12)] and E (P<0.05). There were also significant differences of RPR-T between groups MM [0.37 (0.21; 0.78)] and LH [0.14 (-0.52; 0.50)] (P<0.05), LM [0.41 (0.06; 0.84)] and LH (P<0.05), and LM and E [0.29 (-0.10; 0.68), P<0.05]. A Spearman's correlation analysis showed a negative correlation between RPR and SE in the 15°-30° (P=0.005), 30°-45° (P<0.05) annular (P=0.002), superior (P<0.001), and temporal (P=0.001) quadrants. CONCLUSION: Without pupil dilation, values for RPR 15-30, 30-45, RPR-S, and T shows significant differences between myopic eyes and emmetropia, and the differences are negatively correlated with SE.

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.

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.

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.

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.

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.

Changes in relative peripheral refraction in children who switched from single-vision lenses to Defocus Incorporated Multiple Segments lenses.

PURPOSE: To investigate changes in relative peripheral refraction (RPR) associated with myopia progression in children who wore single-vision (SV) lenses for 2 years and switched to Defocus Incorporated Multiple Segments (DIMS) lenses in the third year versus children who wore DIMS lenses for 3 years. METHODS: In the first 2 years, children were allocated randomly to wear either DIMS or SV lenses. In the third year, children in the DIMS group continued to wear these lenses, while those in the SV group were switched to DIMS lenses (Control-to-DIMS group). Central and peripheral refraction and axial length were monitored every 6 months. RESULTS: Over 3 years, the DIMS group (n = 65) showed good myopia control and maintained a relatively constant and symmetrical RPR profile without significant changes. In the first 2 years, children who wore SV lenses (n = 55) showed asymmetrical RPR changes, with significant increases in hyperopic RPR at 20° nasal (N) (mean difference: 0.88 ± 1.06 D, p < 0.0001) and 30N (mean difference: 1.07 ± 1.09 D, p < 0.0001). The Control-to-DIMS group showed significant myopia retardation after wearing DIMS lenses in the third year. When compared with the RPR changes in the first 2 years, significant reductions in hyperopic RPR were observed at 20N (mean difference: -1.14 ± 1.93 D, p < 0.0001) and 30N (mean difference: -1.07 ± 1.17 D, p < 0.0001) in the third year. However, no significant difference between the RPR changes found in the nasal retina and temporal retina (p > 0.05) was noted in the third year. CONCLUSION: Symmetrical changes in RPR were found in children switching from SV to DIMS lenses, and a symmetrical pattern of RPR was noted in children who wore DIMS for 3 years. Myopia control using myopic defocus in the mid-periphery influenced the RPR changes and retarded myopia progression by altering the eye's growth pattern.

Peripheral refraction, relative peripheral refraction, and axial growth: 18-month data from the randomised study-Clinical study Of Near-sightedness; TReatment with Orthokeratology Lenses (CONTROL study).

PURPOSE: To investigate changes in peripheral and relative peripheral refraction (RPR) during orthokeratology lens (OKL) use in children, and predictors for myopia progression in a randomized controlled trial. METHODS: Refraction and axial length (AL) were measured at baseline, 6, 12, and 18 months for children aged 6-12 years, with myopia of 0.5 to 4.75 dioptres (D) spherical component randomized to either OKL or single-vision spectacles (SVS) at baseline. Cycloplegic spherical equivalent refractive error (SEQ) was measured on-axis and eccentric at 10°, 20°, and 30° during nasal and temporal gaze in the horizontal plane with Shin-Nippon Nvision-K 5001. RPR was computed as SEQ(eccentricity) minus SEQ(on axis) . AL was measured with Lenstar LS900. RESULTS: Twenty-one and 28 subjects from the OKL and SVS groups, respectively were available for analysis. OKL wear induced significant myopic RPR at all eccentricities (p ≤ 0.004) whereas peripheral refraction only changed in two out of six eccentric measuring points. Baseline peripheral refraction SEQ at all eccentricities, baseline on-axis SEQ, and baseline RPR at 30° nasal eccentricity were positively correlated to treatment efficacy defined as change in AL. CONCLUSION: We found no correlations between change in RPR and treatment efficacy defined as change in AL. Interestingly, our results suggest that the central emmetropisation that occurs during OKL-use accounts for most of the optical changes and to a lesser extent the mid-peripheral plus-zone of the lens.

Myopia Control Effect Is Influenced by Baseline Relative Peripheral Refraction in Children Wearing Defocus Incorporated Multiple Segments (DIMS) Spectacle Lenses.

The aim of this study is to investigate if baseline relative peripheral refraction (RPR) influences the myopia control effects in Chinese myopic children wearing Defocus Incorporated Multiple Segments (DIMS) lenses. Peripheral refraction at 10°, 20°, and 30° nasal (10 N, 20 N, 30 N) and temporal (10 T, 20 T, 30 T) retina were measured at six-month intervals for children who participated in a 2-year randomized controlled trial. The relationship between the baseline peripheral refractions and myopia progression and axial length changes were analysed. A total of 79 children and 81 children in the DIMS and single vision (SV) group were investigated, respectively. In the DIMS group, more baseline myopic RPR spherical equivalent (SE) was associated with more myopic progression (10 N: r = 0.36, p = 0.001; 20 N: r = 0.35, p = 0.001) and greater axial elongation (10 N: r = −0.34, p = 0.001; 20 N: r = −0.29, p = 0.006) after adjusting for co-factors. In the SV group, baseline RPR had association with only myopia progression (10 N: r = 0.37, p = 0.001; 20 N: r = 0.36, p = 0.001; 30 N: r = 0.35, p = 0.002) but not with axial elongation after Bonferroni correction (p > 0.008). No statistically significant relationship was found between temporal retina and myopia progression or axial elongation in both groups. Children with baseline myopic RPR had statistically significant more myopia progression (mean difference around −0.40 D) and more axial elongation (mean difference 0.15 mm) when compared with the children having baseline hyperopic RPR in the DIMS group but not in the SV group. In conclusion, the baseline RPR profile may not influence future myopia progression or axial elongation for the SV lens wearers. However, DIMS lenses slowed down myopia progression and was better in myopia control for the children with baseline hyperopic RPR than the children with myopic RPR. This may partially explain why myopia control effects vary among myopic children. Customised myopic defocus for individuals may optimise myopia control effects, and further research to determine the optimal dosage, with consideration of peripheral retinal profile, is warranted.

Overview on Defocus Incorporated Multiple Segments Lenses: A Novel Perspective in Myopia Progression Management.

Myopia is becoming more common across the world, affecting approximately two billion people and rising. Different kinds of therapies (optical, pharmaceutical, environmental, or behavioral) have been proposed to decrease myopia progression, but with variable results and a lack of standardization. The evidence that targeted myopic defocus inhibits eye length growth has paved the way for several contact and spectacle lense designs to induce a peripheral defocus, thus slowing myopia progression, but the perfect configuration has yet to be defined. One of the newest and more promising approaches in this field is the use of Defocus Incorporated Multiple Segments (DIMS) lenses. These lenses are built from the assumption that targeted myopic defocus, produced by 396 mid-peripheral lenslets with positive power, inhibits eye length growth. Recent studies have highlighted the effectiveness of these lenses compared to children who had worn single vision spectacle lenses, in terms of myopia control and tolerability. Despite the evidence that these lenses can help slow down the progression of myopia, the occasional mid-peripheral aberrations they can induce, as well as the overall eye strain that comes with wearing them, should not be overlooked. The aim of this review is to give attention to the advantages and the shortfalls of this new approach and to evaluate its effectiveness in clinical practice.

Comparative Study of Relative Peripheral Refraction in Children With Different Degrees of Myopia.

Purpose: To investigate the difference in the retinal refraction difference value (RDV) using multispectral refractive topography (MRT). Methods: Ninety myopic participants, who met the enrolment requirements, were examined with an automatic optometer after mydriasis. According to the value of the spherical equivalent (SE), the participants were divided into Emmetropia group (E, +0.5D < SE < -0.5D), Low Myopia (LM, -0.5D < SE ≤ -3D), and Moderate and high Myopia (MM, -3D < SE ≤ -10D). The ocular biological parameters were detected by optical biometrics (Lenstar 900, Switzerland), including axial length (AL), lens thickness (LT), and keratometry (K1, K2). Furthermore, the MRT was used to measure the retinal RDV at three concentric areas, with 15-degree intervals from fovea into 45 degrees (RDV-15, RDV 15-30, and RDV 30-45), and four sectors, including RDV-S (RDV-Superior), RDV-I (RDV-Inferior), RDV-T (RDV-Temporal), and RDV-N (RDV-Nasal). Results: In the range of RDV-15, there was a significant difference in the value of RDV-15 between Group E (-0.007 ± 0.148) vs. Group LM (-0.212 ± 0.399), and Group E vs. Group MM (0.019 ± 0.106) (P < 0.05); In the range of RDV 15-30, there was a significant difference in the value of RDV 15-30 between Group E (0.114 ± 0.219) vs. Group LM (-0.106 ± 0.332), and Group LM vs. Group MM (0.177 ± 0.209; P < 0.05); In the range of RDV 30-45, there was a significant difference in the value of RDV 30-45 between Group E (0.366 ± 0.339) vs. Group LM (0.461 ± 0.304), and Group E vs. Group MM (0.845 ± 0.415; P < 0.05); In the RDV-S position, there was a significant difference in the value of RDV-S between Group LM (-0.038 ± 0.636) and Group MM (0.526 ± 0.540) (P < 0.05); In the RDV-I position, there was a significant difference in the value of RDV-I between Group E (0.276 ± 0.530) vs. Group LM (0.594 ± 0.513), and Group E vs. Group MM (0.679 ± 0.589; P < 0.05). In the RDV-T position, there was no significant difference in the value of RDV-T among the three groups. In the RDV-N position, there was a significant difference in the value of RDV-N between Group E (0.352 ± 0.623) vs. Group LM (0.464 ± 0.724), and Group E vs. Group MM (1.078 ± 0.627; P < 0.05). The RDV analysis in all directions among the three groups showed a significant difference between RDV-S and RDV-I in Group LM (P < 0.05). Moreover, the correlation analysis showed that SE negatively correlated with AL, RDV 30-45, RDV-S, RDV-I, and RDV-N. Conclusions: In this study, there was a significant difference in the value of RDV among Group E, Group LM, and Group MM, and the value of RDV in Group MM was the highest on the whole. In the range of RDV 30-45, there was a growing trend with the increase in the degree of myopia among the three groups. Furthermore, the SE negatively correlated with AL, RDV 30-45, RDV-S, RDV-I, and RDV-N.

Relative peripheral refraction characteristics and their relationship with retinal microvasculature in young adults: Using a novel quantitative approach.

AIM: To analyze relative peripheral refraction (RPR) characteristics in young adults and to investigate the relationship between RPR and retinal microvasculature using multispectral refractive tomography (MRT), a novel quantitative approach. METHODS: This cross-sectional study included 278 eyes of 139 young adults. All eyes underwent complete ophthalmic examinations, including MRT, optical coherence tomography angiography (OCTA) and other ocular examinations. Refraction difference values (RDVs) among different rings/sectors were compared using one-way ANOVA in bilateral eyes. Stepwise multiple linear regression analyses were performed between ∆RDV in different rings and ∆density/thickness value in OCTA. RESULTS: Among the different rings, the 30°-45°/45°-53° RDV was significantly greater than the inner rings in both eyes. Among the different sectors, RDV in the superior sector was most significantly reduced among all sectors, and RDV in the nasal sector was significantly greater than that in the temporal sector. In the stepwise multiple linear regression analyses, ∆RDV was negatively correlated with ∆radial peripapillary capillary plexus density and ∆macular thickness. CONCLUSIONS: MRT may be a useful tool in RPR quantitative assessment. RPR and some OCTA indexes might be closely correlated. Further research should be conducted to investigate the relationships among these indexes in young adults.

Alterations in peripheral refraction with spectacles, soft contact lenses and orthokeratology during near viewing: implications for myopia control.

CLINICAL RELEVANCE: The peripheral refraction profile in myopes with different corrective modalities varies significantly for both distance and near viewing and will have implications in managing myopia. BACKGROUND: This study investigated how the magnitude of peripheral myopic defocus induced by Ortho-K varies with and without accommodation, and how this compares to single vision spectacles and soft-contact-lenses (SCL). METHODS: Relative peripheral refraction (RPR) of 18 young adults (spherical equivalent -1.00 D to -4.50 D) was determined along the horizontal meridian (±10°, ±20°, ±25°) during distance (3-metres) and near viewing (0.2-metres), and along vertical meridian (±10°, ±15°) for distance viewing alone. Measurements were obtained in an uncorrected state and with single vision spectacles, soft contact lens and Ortho-K. Changes in RPR and astigmatic components were compared between distance and near viewing with all different modalities. RESULTS: A significant interaction (p = 0.02) between relative peripheral refraction and the target distance (distance and near viewing) was found among different refractive modalities. Single overnight Ortho-K lens wear alone led to relative peripheral myopia for both distance (mean RPR ± SE: -0.92 ± 0.21D and -1.04 ± 0.22D) and near viewing (-0.71 ± 0.17D and -0.76 ± 0.20D). Comparisons of relative peripheral refraction between different corrective modalities at each eccentricity indicated statistical significance of RPR at extreme locations along both temporal and nasal meridian (±20 and ±25°, p < 0.05). RPR with soft contact lenses and spectacles were similar for both distance and near viewing (p > 0.05). CONCLUSION: Single overnight Ortho-K lens wear alone shifted the RPR in the myopic direction for both distance and near viewing in comparison with single vision spectacles and soft contact lenses. The Ortho-K lens designs that offer a large amount of mid-peripheral corneal steeping, in-turn leading to high relative peripheral myopia for both distance and near viewing and might offer beneficial effects on myopia control.

Nasal-temporal asymmetric changes in retinal peripheral refractive error in myopic adolescents induced by overnight orthokeratology lenses.

Objective: To observe the changes in peripheral refraction in myopic adolescents after overnight orthokeratology and its influencing factors. Methods: This was a prospective study among young myopic adolescents aged 8-14 years (n = 21). The peripheral refraction of the subjects was measured at 5, 10, 15, 20, 25, and 30° from the nasal and temporal side to the central fixation by WAM-5500 Open-field refractometer. The axial length, baseline spherical equivalent refraction, and other parameters were measured. The data were measured at baseline and 1, 3, and 12 months after wearing orthokeratology lenses. Results: The relative peripheral refraction at the nasal and temporal side from central to 30° eccentricity revealed relative hyperopic defocus in all subjects at baseline measurement. One month after wearing the orthokeratology lenses, the relative peripheral refraction changed to myopic defocus, the nasal-temporal relative peripheral refraction was asymmetric, and the observed difference was statistically significant. Positive correlations were found between the change amount of nasal relative peripheral refraction and baseline spherical equivalent refraction, the baseline nasal relative peripheral refraction was higher than that on the temporal side, and after orthokeratology, the value of nasal relative peripheral refraction was lower than that on the temporal side. The changes at 30° on both sides were correlated to the axial elongation (rNasal = 0.565, rTemporal = 0.526, p < 0.05). Conclusion: This study demonstrated that after orthokeratology, relative peripheral hyperopia in the myopic patients turned into relative peripheral myopia, and the nasal-temporal asymmetry changed significantly after orthokeratology, which was correlated with the baseline refractive state.