Peripheral vision can influence eye growth and refractive development in infant monkeys

Four-Year Longitudinal Investigation of the Relationship Between Myopia and Retinal Shape in Chinese Children: The Anyang Childhood Eye Study

PURPOSE

To investigate the longitudinal relationship between myopia and retinal shape in Chinese children.

METHODS

A total of 2471 seven-year-old Chinese children were measured for axial length, anterior corneal radius of curvature, anterior chamber depth, lens thickness, central spherical equivalent, and peripheral refractions along the horizontal meridian (±15°, ±30°) under cycloplegia. Retinal shape was fitted using vertex radius of curvature, asphericity, and an offset. The areas under the horizontal retinal curve, the nasal side of areas under the horizontal retinal curve and the temporal side of areas under the horizontal retinal curve, were calculated. Children were tested annually for 5 years from year 0 to 4, with 1123 newly developed myopes divided into eight subgroups based on relative time to myopia onset.

RESULTS

In follow-up subgroups, vertex radius of curvature showed positive correlations with central spherical equivalent from years 1 to 4. Smaller temporal side of areas under the horizontal retinal curve was associated with negative central spherical equivalent each year. Myopic shift (Δcentral spherical equivalent) was negatively correlated with baseline central spherical equivalent and with greater change in areas under the horizontal retinal curve from year 0 to 4. The absolute change in temporal side of areas under the horizontal retinal curve (0.39 ± 1.15 mm2) was significantly larger than the absolute change in nasal side of areas under the horizontal retinal curve (0.05 ± 1.11 mm2) over the 4 years. In myopia onset subgroups, temporal side of areas under the horizontal retinal curve was significantly smaller than nasal side of areas under the horizontal retinal curve. The ratio of temporal side of areas under the horizontal retinal curve/nasal side of areas under the horizontal retinal curve was closest to 1 in the year before myopia onset and decreased as myopia developed. Vertex radius of curvature, areas under the horizontal retinal curve, and temporal side of areas under the horizontal retinal curve decreased linearly as myopia progressed.

CONCLUSION

A progressive steepening of the horizontal posterior retina was associated with myopia progression. Myopia shift was negatively correlated with baseline central spherical equivalent and with greater change in posterior retinal shape. As myopia progressed, the horizontal retina shape displayed increased asymmetry.

Visual Acuity and Refractive Status in Congenital Macular Coloboma

PURPOSE

We analysed the refractive state and the factors that influence the best-corrected visual acuity (BCVA) in congenital macular coloboma (CMC) to provide new ideas for improving and predicting the vision of patients with CMC.

METHODS

We reported three patients and reviewed 26 cases of CMC reported in the China National Knowledge Infrastructure (CNKI) database. We measured the BCVA, spherical equivalent refraction (SER), the macular coloboma's diameter and area, and the distance from the macular coloboma's nasal edge to the optic disc's temporal edge (DISTANCE). We analyzed the refractive status of CMC and the factors affecting BCVA.

RESULT

The three patients with CMC we reported all had myopia. The study also included 26 patients with CMC reported in the CNKI database (9 unilateral, 17 bilateral) and we analyzed the findings of 26 patients with 43 eyes. The mean age at diagnosis was 22.96 ± 2.32 years. All patients underwent a comprehensive eye examination; 39 eyes (91%) had myopia (44% mild myopia; 28% moderate myopia; 28% high myopia); 23 eyes (53%) had a BCVA ≤6/60 and other 20 eyes (47%)>6/60. No correlation was found between SER or BCVA and the macular coloboma's diameter or area. BCVA correlated positively with DISTANCE (r = 0.603, p < 0.001). No correlation was found between SER and DISTANCE. The study found a significant difference in SER or BCVA between the affected and fellow eyes in patients with unilateral CMC (n = 9, T=-3.259, p = 0.012; Z=-2.521, p = 0.012, respectively).

CONCLUSION

CMC seriously affects visual acuity. The refractive state is mostly myopia. We hypothesize that the DISTANCE is related to the integrity of the papillomacular bundle and affects BCVA.

Correlation Between Relative Peripheral Refraction and Efficacy of Myopia Control After Wearing Multifocal Soft Contact Lenses in Children

INTRODUCTION

This study investigated the relationship between relative peripheral refraction (RPR), retinal choroidal vessel, and the growth rate of axial length (AL) in children with myopia wearing multifocal soft contact lenses (MiSight CLs).

METHODS

Forty-four eyes of 44 children with myopia wearing MiSight CLs were included in the study. RPRs and retinal choroidal vessel were measured at baseline, 3 months, 6 months, and 1 year using multispectral refraction topography (MRT) and optical coherence tomography angiograghy (OCTA). MRT presented RPR at different fields of view and OCTA presented retinal choroidal vessel characteristics centered on the macula. The correlation between the changes of RPR (ΔRPRs) and the growth rate of AL was analyzed.

RESULTS

The baseline AL, spherical equivalent, age, and average growth rate of AL of children are 24.76 ± 0.95 mm,  - 3.22 ± 1.77 D, 11.25 ± 2.42 years, and 0.22 ± 0.17 mm/year. At 3 months, TRPR (RPR of the circular visual field of 53° centered on macular fovea) (p = 0.0007), RPR-15 (p = 0.0042), RPR-30 (p = 0.0012), RPR-45 (p = 0.0031), and RPR-I (p = 0.0082) of children with myopia wearing MiSight CLs were significantly lower than baseline. The ΔRPR was negatively correlated with the growth rate of AL (ΔTRPR, r = - 0.43, p = 0.003; ΔRPR-45, r = - 0.43, p = 0.004; ΔRPR-I, r = - 0.35, p = 0.02; ΔRPR-N, r = - 0.32, p = 0.04). At 1 year, there was a significant difference in the retina vessel volume index compared to baseline (p = 0.0002).

CONCLUSION

RPR showed significant changes at 3 months after wearing multifocal soft contact lenses, but noticeable changes in retinal vessel volume index occurred only at 1 year. MRT demonstrates a higher efficacy in the early detection of the effectiveness of myopia control measures.

Peripheral Refraction and Axial Growth Rate After Multifocal or Monofocal Intraocular Lens Implantation in Chinese Pediatric Cataract Patients

Purpose

The purpose of this study was to compare relative peripheral refraction (RPR) and axial growth in Chinese pediatric patients with cataract who underwent multifocal or monofocal intraocular lens (IOL) implantation.

Methods

Pediatric patients with cataract aged 3 to 6 years who underwent IOL implantation from 2020 to 2021 were enrolled in this study. The patients received multifocal or monofocal IOL implantations with optic capture in Berger's space. The axial length (AL) was measured with a Zeiss IOL Master 700, and autorefraction at the horizontal retina within 30 degrees eccentricities was recorded with a Grand Seiko WAM-5500 autorefractor. The RPR was calculated by subtracting the central refraction from the peripheral refraction. The axial growth rate was calculated as the change in the AL divided by the number of follow-up years.

Results

Twenty-six children (38 eyes) implanted with multifocal IOLs and 19 children (30 eyes) implanted with monofocal IOLs completed the study. No significant differences were observed in preoperative characteristics between the two groups (P > 0.05). The generalized estimating equation (GEE) model revealed that the axial growth rate was significantly associated with the IOL type (P = 0.049) after adjusting for surgical age and follow-up intervals, with multifocal IOL eyes showing lower annual growth rate than monofocal IOL eyes. Additionally, compared with monofocal IOL eyes, multifocal IOL eyes exhibited greater peripheral myopic defocus at 20 degrees and 30 degrees on the temporal retina (P < 0.001 and P = 0.005, respectively). The GEE model also revealed a positive correlation between the annual axial growth rate and the 20 degrees temporal retina RPR (P = 0.018).

Conclusions

Chinese pediatric patients with cataract who underwent multifocal IOL implantation exhibited less axial growth, potentially caused by greater peripheral myopic defocus.

Synergistic effect of defocus incorporated multiple segment glasses and repeated low level red light therapy against myopia progression

Defocus incorporated multiple segment (DIMS) lenses and repeated low-level red-light (RLRL) are used to retard myopia progression. However, it is currently unknown if there is a synergistic effect of the two interventions. In the current study, 190 school-aged children with myopia (380 eyes) were studied for the change in axial length (AL) over nearly one year of follow-up. Of 380 eyes, 170 eyes wore DIMS lenses, 80 eyes had RLRL therapy, and 130 eyes had both interventions (DIMS_RLRL) for myopia control. AL changes were calculated at each follow-up visit by subtracting the baseline measurements and normalized to yearly changes in mm. AL changes as a primary outcome were analyzed in a generalized linear mixed model to compare effect sizes of myopia control among three interventions while adjusting for age, sex, baseline axial length, and follow-up length. Participants had a mean age of 9.84 ± 2.63 years old, mean AL of 24.49 ± 1.20 mm, mean SER of -2.90 ± 2.08 diopters, and mean follow-up time of 301 ± 91 days. By the end of the study, the adjusted mean yearly axial change with combination therapy was - 0.13 mm, -0.04 mm for the eyes with RLRL alone, and 0.16 mm for the eyes with DIMS lenses alone (p < 0.0001). Combination therapy of DIMS and RLRL has significantly greater effect size in controlling myopia progression than either RLRL alone (p = 0.0009) or DIMS alone (p < 0.0001).

Peripheral Defocus in Orthokeratology Myopia Correction: Systematic Review and Meta-Analysis

Background: This study aimed to assess the effect of peripheral defocus with orthokeratology lenses (PDOK) on myopia control in children and adolescents through a systematic review and meta-analysis. Methods: A comprehensive search was conducted in the PubMed and Web of Science databases to identify randomized controlled trials (RCTs) and cohort studies on PDOK, using the keywords "peripheral refraction" and "orthokeratology". Studies were included if they reported spherical equivalent (M) peripheral refraction at 25° and/or 30° with accompanying statistical data along the horizontal meridian before and after orthokeratology treatment. From the initial 133 studies, those excluded included nine non-English publications, 18 reviews, five meta-analyses, four systematic reviews, and 88 studies not meeting the inclusion criteria. Results: Nine studies (three RCTs and six cohort studies) were included, involving 259 participants aged six to 30 years with a baseline refractive error of M = -2.44 ± 0.27 D, and treatment duration ranging from 14 days to 12 months. All the studies showed an increase in myopic defocus at 30° nasal (-2.55 ± 1.10 D) and temporal (-2.79 ± 0.75 D) eccentricities, averaging -2.67 ± 0.95 D across both. The overall induced myopic defocus was M = -2.56 D (95% CI: -2.21 to -2.91, Z = 14.33, p < 0.001), according to forest plot analysis. Studies with treatment durations up to one year showed a higher myopic blur (M = -2.69 D, 95% CI: -2.48 to -2.89, Z = 25.93, p < 0.001) compared to shorter treatments of less than three months (M = -2.39 D, 95% CI: -1.76 to -3.02, Z = 7.41, p < 0.001). Conclusions: Orthokeratology lenses effectively induce myopic defocus at 30° eccentricity over both short- and long-term treatments in children and adolescents, suggesting potential benefits for myopia control in these age groups.

Exemplifying practice-based research: the influence of age on myopia progression

CLINICAL RELEVANCE

The electronic storage of patient records and modern-day search engines present private practitioners with a unique opportunity to extract valuable data for investigative research purposes. However, practitioners seldom harness this resource and consequently a vast repository of clinical data remains largely unexplored.

BACKGROUND

This study, based on real-world data from an optometric practice, stands as an example of how clinicians can actively contribute to research. In doing so it underscores the role played by age in determining the rate of natural myopia progression.

METHODS

A retrospective data analysis of the refractive status, age and optical correction type of participants, was conducted over six years. Forty-four participants were recruited (25 contact lens and 19 spectacle wearers), with a presenting age varying from 5 to 20 years (median, 11 years). Non-cycloplegic, monocular foveal refractions were completed using a ShinNippon open-field autorefractor, corroborated with subjective refraction. The mean spherical equivalent refractive error was calculated for the participants' initial visit (baseline measure) and for a six-year follow-up visit (progression measure), with myopia progression defined as the difference between these measures. Statistical analyses were computed using Decision Tree Analysis, with a significance level set at 95%.

RESULTS

The participant age at first visit exerted a significant influence on natural myopia progression over the assessment period (F 1,42 = 17.11, p < 0.001). Individuals aged ≤ 10 years had approximately twice the myopic progression (mean, -2.27 D) of those aged > 10 years (mean, -1.13 D). Neither degree of myopia at the initial visit nor optical correction type had a significant effect on progression (p > 0.05).

CONCLUSIONS

Utilizing the advantage of small real-world data samples, the benefit of research by private practitioners was demonstrated, providing evidence that the age at which a child first presents for an eye examination is highly influential in determining their rate of myopia progression.

Outdoor activity during class recess prevents myopia onset and shift in premyopic children: Subgroup analysis in the recess outside classroom study

PURPOSE

To investigate whether premyopia is a risk factor for myopia onset and whether outdoor activities can protect against myopia development in premyopic children in the Recess Outside Classroom (ROC) study.

METHODS

Nonmyopic schoolchildren aged 7-11 years were recruited from two schools in Taiwan. One school implemented the ROC program, which encouraged children to go outdoors during recess. The control school maintained its usual schedule. A cycloplegic autorefraction was performed. Premyopia was defined as spherical equivalent refraction ≤ +0.75 diopters (D) and > -0.50 D.

RESULTS

After one year of follow-up, multivariate logistic analysis revealed that the ROC program reduced the risk of myopia onset by 61 % (odds ratio [OR] = 0.39, 95 % confidence interval [CI]: 0.21-0.70, P = 0.002). However, premyopia status increased the risk of myopia onset by 14 times compared to hyperopic status (OR = 14.0, 95 % CI: 1.86-105.3, P = 0.010). In the subgroup analysis of premyopic children, the myopic shift was also significantly lower in the ROC group than in the control group (-0.20 ± 0.60 D/year vs. -0.40 ± 0.66 D/year, P = 0.017). Myopia incidence in premyopic children was significantly lower in the ROC group than in the control group (19.6 % vs. 37.8 %, P = 0.001). Multivariate regression analysis showed that participation in the ROC program was significantly associated with a lower myopic shift in premyopic children (-0.22 D/year, 95 % CI: -0.39 to -0.06, P = 0.008) CONCLUSIONS: Premyopia is a risk factor for myopia onset. A school policy that includes more outdoor time can effectively prevent myopia onset and shift in premyopic children.

Changes in relative peripheral refraction after implantable collamer lenses implantation

PURPOSE

This study aimed to measure the changes in refraction difference value (RDV) in different parts of the retina before and after implantable collamer lenses (ICL) surgery.

DESIGN

Prospective study.

METHODS

This study included 40 eyes of 40 patients who underwent ICL implantation for myopia. RDV measurements were taken across several ranges: 0°-15°, 15°-30°, 30°-45°, and 45°-53°, and categorized into four sectors: superior (RDV-S), inferior (RDV-I), temporal (RDV-T), and nasal (RDV-N), along with total RDV (TRDV). Measurements were taken preoperatively, and at one week and one month postoperatively.

RESULTS

TRDV, RDV beyond 15° eccentricity, and RDV-S, RDV-I, RDV-T, and RDV-N were significantly increased postoperatively. The one-week and one-month follow-up of RDVs had no significant differences. Significant differences in the increments were observed among RDV-15, RDV-15-30, RDV-30-45, and RDV-45-53 both at one-week and one-month follow-up. Similarly, there were significant differences in the increments among RDV-S, RDV-I, RDV-T, and RDV-N both at one-week and one-month follow-up. TRDV, RDV-30-45, RDV-45-53, RDV-S, RDV-T, and RDV-N showed significant differences in the variation preoperatively and postoperatively between the high (SE > -9.00 D) and ultra-high (SE ≤ -9.00 D) myopia groups.

CONCLUSIONS

Peripheral refraction showed a hyperopic defocused state that can stabilize in the early postoperative period after ICL implantation. The variation in the hyperopic defocused shift in peripheral refraction increased more in the regions farther from the central retina. The temporal regions exhibited the most changes.

KEY MESSAGES

WHAT IS KNOWN : Myopia is generally believed to stabilize after adulthood, but some individuals continue to experience myopia progression, accompanied by axial length elongation. Traditional spectacle lenses correct myopia by focusing light on the fovea but may introduce peripheral hyperopic defocus, which is thought to contribute to myopia progression. ICL surgery effectively corrects high degrees of myopia and astigmatism. Previous studies have demonstrated the safety and efficacy of ICL in addressing central refractive errors, but peripheral refraction changes post-surgery have not been well-explored.

WHAT IS NEW

ICL surgery increased peripheral hyperopic defocus while correcting central refractive error, with significant changes in peripheral refraction observed from the preoperative to postoperative one-week and one-month.. After ICL implantation, a hyperopic shift was observed in peripheral areas, with RDV values within 15° of the central retina appearing emmetropic and increasing hyperopic defocus noted moving away from the posterior pole. Peripheral refraction stabilized approximately one week after ICL surgery, with no significant differences observed between the one-week and one-month follow-ups, indicating that stability in peripheral refraction is typically achieved within this timeframe.

Clinical and mutational signatures of CRB1-associated retinopathies: a multicentre study

BACKGROUND

To delineate the clinical and mutational signatures of patients with CRB1-associated retinopathies.

METHODS

This multicentre retrospective cohort study involved 40 patients with CRB1 mutations and 40 age-matched and gender-matched inherited retinal diseases (IRDs). The detailed phenotyping and genotyping characteristics and genotype‒phenotype correlations of the patients were analysed.

RESULTS

The mean age of CRB1 cohort was 27.33±14.63 years. Results showed that yellowish geographic macular degeneration (66.67%), small white or yellow dots (65.6%), hyperopia (62.5%), abnormally laminated retina (61.61%), epiretinal membrane (60.6%) and nummular pigment deposits (50%) were the most common signatures in patients with CRB1 mutations. These clinical signatures were notably more prevalent among CRB1 patients than among individuals in other IRD groups (p<0.001). Early-onset severe retinal dystrophy/Leber congenital amaurosis (EOSRD/LCA) patients are more likely to present these signatures than retinitis pigmentosa (RP) and macular dystrophy (MD) patients. Furthermore, a significant reduction in central foveal thickness coupled with pronounced thickening of the peripheral retina was observed more distinctly in patients with EOSRD/LCA (p<0.001). The choroidal thickness was not significantly altered compared to the normal controls, but was markedly reduced in the other IRD groups (p<0.001). 55 pathogenic variants were identified, 20 of which were novel. Null mutations were associated with EOSRD/LCA patients, and missense mutations were more prevalent in MD and RP patients.

CONCLUSIONS

Key clinical and mutational signatures were demonstrated in this study, providing a comprehensive update on CRB1-associated retinopathies that will aid in diagnosis and lay the foundation for future therapeutic studies.

Role of angiopoietin-like 4 in neovascularization associated with retinopathy of prematurity

To elucidate the mechanisms of angiopoietin-like 4 (ANGTPL4) in neovascularization (NV) in retinopathy of prematurity (ROP). We compared ANGPTL4 expression levels of aqueous humour and vitreous fluid samples in infants with acute-phase ROP and control group. ANGPTL4-/- mice and WT mice were used to constructed oxygen-induced retinopathy (OIR) mouse models, with retinal tissues collected on postnatal days 12 (P12), 15 (P15) and 17 (P17). Analysis of retinal vessels and transcriptomics were performed to explore the role of ANGTPL4 in NV. The results showed ANGPTL4 level was significantly higher in the aqueous humour and vitreous fluid of children with ROP than that of control group. At P15 and P17, the vascular indices in the ANGPTL4-/--CON group were lower than those in the WT-CON group. The central non-perfused area of the retina and number of neovascular nuclei were also smaller in the ANGPTL4-/--OIR group than in the WT-OIR group. Immunofluorescence results showed the overexpression of ANGPTL4 protein in the WT-OIR group than in the WT-CON group, especially at P17. Furthermore, extracellular matrix (ECM) organisation was one of the key involved pathways based on gene ontology (GO) enrichment analyses. ANGPTL4 was one of the core genes involved in ECM organization, and neuralized E3 ubiquitin protein ligase 1B (NEURL1B), cd36 Molecule (CD36), matrix metallopeptidase 3 (MMP3) and collagen type III alpha 1 chain (COL3A1) were the first nodes interacting with ANGPTL4.In conclusion, ANGPTL4 is involved in the pathological NV by regulating NEURL1B, CD36, MMP3, and COL3A1. Thus, ANGPTL4 is a potential therapeutic target for ROP.

Peripheral refraction of young adults with myopia: a cross-sectional study

OBJECTIVE

Peripheral refraction is associated with myopia development. Due to a varying prevalence of myopia across different ethnic groups, the aim of the present study was to investigate the peripheral refraction profile in an Arabic population.

METHODS

Adults attending an optometry clinic were recruited into this cross-sectional study. Peripheral refraction of the right eyes was measured using an open field autorefractor under noncycloplegic conditions along the temporal-nasal meridians (15° and 35°) in participants with emmetropia, or low, moderate, or high myopia. Refractions were converted into power vector components, including the spherical equivalent of central refraction, J0 and J45 astigmatism. STROBE guidelines were followed for study reporting.

RESULTS

A total of 138 adults (aged 20-29 years) were enrolled. Relative peripheral refractive error (RPRE) varied between refractive groups and increased with eccentricity. The RPRE was more hyperopic in myopia groups, with the nasal visual field being more hyperopic. A significant relationship was found between RPRE and central refraction, but not with J0 and J45 scores.

CONCLUSIONS

Participants with moderate myopia exhibited more hyperopic RPRE compared with previous findings in other ethnic groups. Hyperopic RPRE was significantly associated with myopia. Accurate RPRE measurement are essential for designing personalized lenses to slow down myopia progression. This study provides an RPRE baseline in the population investigated, which will be useful for future studies on personalized lens design, including spectacles and contact lenses.

Retinal "sweet spot" for myopia treatment

We studied which retinal area controls short-term axial eye shortening when human subjects were exposed to + 3.0D monocular defocus. A custom-built infrared eye tracker recorded the point of fixation while subjects watched a movie at a 2 m distance. The eye tracker software accessed each individual movie frame in real-time and covered the points of fixation in the movie with a uniform grey patch. Four patches were programmed: (1) foveal patch (0-3 degrees), (2) annular patch (3-9 deg), (3) foveal patch (0-3 deg) combined with an annular patch (6-9 deg), and (4) full-field patch where only 6-10 deg were exposed to the defocus. Axial eye shortening was elicited similarly with full-field positive defocus and with the foveal patch, indicating that the fovea made only a minor contribution (-11 ± 12 μm vs. -14 ± 17 μm, respectively, n.s.). In contrast, patching a 3-9 degrees annular area or fovea together with an annular area of 6-9 degrees, completely suppressed the effect when compared with full-field defocus (+ 3 ± 1 μm or -2 ± 13 μm vs. -11 ± 12 μm, respectively, p < 0.001). Finally, we found that the near-peripheral retina (6-10 degrees) is a "sweet spot" for positive defocus detection and alone can regulate eye growth control mechanism, and perhaps long-term refractive development (-9 ± 8 μm vs. full-field: -11 ± 12 μm, n.s.).

Ultra-wide-angle peripheral refraction using a laser-scanning instrument

We compared the peripheral refractive measurements of a recently proposed laser-scanning instrument with an established peripheral refractor. Two-dimensional refractive maps were obtained using both instruments for 18 young subjects with differing values of central refraction. The comparison shows a strong correlation between devices in the overlapping measurement area, with the new device extending the range of the explored retinal area to a 100-degree-diameter circular patch, compared to the 60°x35° rectangular area of the older peripheral refractor. Larger refractive maps exhibit trends that cannot be easily predicted from narrower scans. These results demonstrate that the new instrument can be a useful tool for assessing wide-angle peripheral optical data in the human eye.

Observations on relative peripheral refraction in Chinese adults with myopia based on a novel application of multispectral refraction topography

In this population-based observational cross-sectional study, we investigated retinal peripheral refraction in Chinese adults with myopia. We categorized 1511 Chinese adults with myopia (18 - 55 years) into low (LM), moderate (MM), and high myopia (HM) groups. Axial length, central corneal thickness, steep keratometry, flat keratometry, and intraocular pressure were measured. Refractive difference values (RDVs) for different eccentricities (RDV0-53) and the superior (RDV-S), inferior (RDV-I), temporal (RDV-T), and nasal (RDV-N) retinal regions were measured using multispectral refractive topography. The hyperopic defocus was higher for the MM group than for the LM group in RDV20-53, RDV-S, and RDV-T and HM group in RDV20-53, RDV-S, RDV-T and RDV-N. The hyperopic defocus was higher for the HM group than for the LM group in RDV20-53, RDV-S and RDV-T but lower for the LM group in RDV-N. RDV-N decreased with age (R2 = 0.0191, slope = - 0.01, p < 0.0001), whereas RDV-S (R2 = 0.0112, slope = 0.01,p < 0.0001) and RDV-T increased (R2 = 0.0038, slope = 0.01, p = 0.0160). RDV correlated with central spherical equivalent and axial length. Flat keratometry explained the most RDV variation (RDV20-30: β = 0.0714, p < 0.0001; RDV-N: β = 0.1801, p < 0.0001; RDV-S: β = 0.1426, p < 0.0001; RDV-T: β = 0.1239, p < 0.0001). Reference values for peripheral retinal defocus are provided for Chinese adults with different myopia ranges.

One-year efficacy of myopia control by the defocus distributed multipoint lens: a multicentric randomised controlled trial

AIMS

To report the 1-year results of the efficacy of a defocus distributed multipoint (DDM) lens in controlling myopia progression in a multicentre, randomised controlled trial.

METHODS

Overall, 168 children aged 6-13 years were recruited and randomly assigned to wear a DDM lens (n=84) or single-vision (SV) lens (n=84) in three centres. Cycloplegic autorefraction (spherical equivalent refraction (SER)) and axial length (AL) were measured. Linear mixed model analysis was performed to compare between-group SER and AL changes. Logistic regression analysis was used to analyse the between-group difference in rapid myopia progression (SER increase≥0.75 D per year or AL growth≥0.40 mm per year).

RESULTS

After 1 year, mean changes in SER were significantly lower in the DDM group (-0.47±0.37 D) than in the SV group (-0.71±0.42 D) (p<0.001). Similarly, mean changes in AL were significantly lower in the DDM group (0.21±0.17 mm) than in the SV group (0.34±0.16 mm) (p<0.001). After adjusting for age, sex, daily wearing time and parental myopia, rapid myopia progression risk was higher in the SV group than in the DDM group (OR=3.51, 95% CI: 1.77 to 6.99), especially for children who wore a lens for >12 hours per day, boys and younger children (6-9 years) with ORs (95% CIs) of 10.82 (3.22 to 36.37), 5.34 (1.93 to 14.78) and 8.73 (2.6 to 29.33), respectively.

CONCLUSIONS

After 1 year, DDM lenses effectively retarded myopia progression in children. Longer daily wearing time of DDM lens improved the efficacy of myopia control. Future long-term studies are needed for validation.

TRIAL REGISTRATION NUMBER

NCT05340699.

Regional Summed Corneal Refractive Power Changes in Myopic Orthokeratology and Their Relationships With Axial Elongation

PURPOSE

To determine the relationship between regional summed corneal refractive power changes (CRPCs) in myopic orthokeratology and axial elongation.

DESIGN

This retrospective study included 70 eyes of 70 patients aged 8 years to 13 years who underwent orthokeratology lens (OK lens) treatment, and all patients underwent regular follow-ups at 1 week, 1 month, 6 months, and 12 months at Zhongshan Ophthalmic Center between January 2019 and May 2021.

METHODS

Axial length (AL) was measured at baseline and 12 months by an IOLmaster 5.0. Refractive error power was measured using cycloplegia. Regional summed CRPCs were calculated by MATLAB software using difference tangential power maps at the sixth month acquired by corneal topography measurements (Medmont E300 Corneal Topographer; Medmont Pty, Victoria, Australia) and defined as changes in corneal refractive power at the sixth month from baseline. The regional summed CRPCs were then subdivided into 4-mm diameter circles, 4- to 5-mm diameter chords, and 5- to 6-mm diameter chords according to the distance from the central of the pupil and into negative, positive, and total according to the values. Pearson correlation, multiple linear regression analysis, and stepwise multiple linear regression analysis were performed to analyze the relationships among these parameters.

RESULTS

Axial elongation had a negative relationship with positive regional summed corneal refractive power in the central 4-mm diameter circle and age (r=-0.282, P =0.018; r=-0.473, P <0.001, respectively) and a positive relationship with negative regional summed corneal refractive power in the 5- to 6-mm diameter chord (r=0.361, P =0.002). Stepwise multiple linear regression analysis identified age (standardized β =-0.434, P <0.001) and negative regional summed corneal refractive power in the 5- to 6-mm diameter chord (standardized β =0.305, P =0.004) as factors influencing AL elongation.

CONCLUSION

Negative regional summed corneal refractive power in a 5- to 6-mm diameter chord after OK lens treatment may be an important index for evaluating the control effects of axial elongation.

Impact of Genetic and Environmental Factors on Peripheral Refraction

Purpose

Investigate genetic and environmental influences on refractive errors in monozygotic (MZ) and dizygotic (DZ) twin pairs.

Methods

We assessed foveal and peripheral refractions in 54 MZ and 46 DZ twins, capturing three scans across the retina. The study focused on spherical equivalent (M) at the fovea (MLOS) and changes in midperipheral (δMmid-periphery), and peripheral (δMperiphery) defocus, along with nasal-temporal asymmetry (root mean squared error [RMSEASY]) and image shell contour (RMSEAVG). Genetic and environmental contributions were analyzed using structural equation models.

Results

No significant differences were observed between MZ and DZ twins for the examined variables. Intraclass correlations (ICC) indicated an important difference in genetic influence between MLOS, with the MZ twin pairs showing a higher correlation (0.83) than DZ (0.69) pairs, and δMperiphery, because the ICC for the MZ doubled (0.87) that of the DZ (0.42) pairs. Heritability estimates from the ACE model confirmed the large difference on genetic factors' influence on the variance for MLOS (0.13) and δMperiphery (0.77) change in refractive error. RMSEASY and RMSEAVG metrics showed significant genetic impact, particularly pronounced in the peripheral measurements, revealing high genetic control.

Conclusions

The study delineates a marked environmental impact on central refractive errors, whereas genetic factors had a more significant influence on peripheral refractive variance and retinal image traits. Findings of the ACE model highlight the intricate genetic and environmental interplay in refractive error development, with a notable genetic dominance in peripheral vision characteristics. This suggests potential genetic targets for interventions in myopia management and emphasizes the need for personalized approaches based on genetic predispositions.

Translational Relevance

Understanding the impact of genetics and environment on peripheral refraction is essential for deepening our fundamental knowledge of myopia and guiding the development of advanced myopia control strategies.

The impact of different postures on acute intraocular pressure and accommodation responses during reading

INTRODUCTION

To investigate the effects of different reading postures on intraocular pressure (IOP) and near-work-induced transient myopia (NITM) in children with myopia.

METHODS

Sixty myopic children were instructed to read a book text placed at 33 cm for 30 min with two different reading postures: head bowed and head upright postures. The participants' IOP and NITM were assessed using a rebound tonometer and an open-field autorefractor. The measurement of IOP was conducted prior to reading, during reading sessions (at 5, 10, 20, and 30-min intervals), and after a 5-min recovery period.

RESULTS

For the head bowed posture, the mean baseline IOP was 16.13 ± 2.47 mmHg. A significant rise in IOP was observed after 5 min of reading (17.17 ± 2.97 mmHg; +1.03 ± 2.29 mmHg; p = 0.014). Subsequent measurements revealed a further increase after 20 min (17.87 ± 2.90 mmHg; +1.73 ± 2.58 mmHg; p < 0.001), which continued to persist even after 30 min of reading (17.57 ± 3.46 mmHg; +1.43 ± 2.66 mmHg; p = 0.002). The IOP at different time points measured in the head upright posture did not show any significant difference in comparison to the baseline measurement (all p = 1.000). Compared to reading with the head upright, reading with the head bowed resulted in a greater increase in IOP at each time point (p < 0.05). Furthermore, the NITM was higher for reading with the head bowed than for reading with head upright at 30 min (-0.24 ± 0.53 D vs. -0.12 ± 0.47 D, p = 0.038).

CONCLUSION

Reading in a head bowed position resulted in greater increases in IOP and NITM compared to reading in a head upright posture.

Acute Effects of Oral Caffeine Intake on Human Global-Flash mfERG Responses: A Placebo-Controlled, Double-Masked, Balanced Crossover Study

Purpose

To determine the acute effect of caffeine intake on the retinal responses as measured with a global-flash multifocal electroretinogram (gfmERG) protocol at different contrast levels.

Methods

Twenty-four young adults (age = 23.3 ± 2.4 years) participated in this placebo-controlled, double-masked, balanced crossover study. On two different days, participants orally ingested caffeine (300 mg) or placebo, and retinal responses were recorded 90 minutes later using a gfmERG at three contrast levels (95%, 50%, and 29%). The amplitude response density and peak time of the direct and induced components (direct component [DC] and induced component [IC], respectively) were extracted for five different eccentricities (1.3°, 5.0°, 9.6°, 15.2°, and 21.9°). Axial length, spherical equivalent refraction, habitual caffeine intake, and body weight were considered as continuous covariates.

Results

Increased IC amplitude response density was found after caffeine ingestion in comparison to placebo (P = 0.021, ƞp2 = 0.23), specifically for the 95% and 50% stimulus contrasts (P = 0.024 and 0.018, respectively). This effect of caffeine on IC amplitude response density was independent of the retinal eccentricity (P = 0.556). Caffeine had no effect on DC amplitude response density or DC and IC peak times.

Conclusions

Our results show that oral caffeine intake increases the inner electro-retinal activity in young adults when viewing stimuli of high- (95%) to medium-contrast (50%). Given the increasing evidence that the inner retinal function is involved in the emmetropization process, these results may suggest that caffeine or its derivatives could potentially play a role in the mechanisms involved in eye growth.

Insights into Myopia from Mouse Models

Animal models are critical for understanding the initiation and progression of myopia, a refractive condition that causes blurred distance vision. The prevalence of myopia is rapidly increasing worldwide, and myopia increases the risk of developing potentially blinding diseases. Current pharmacological, optical, and environmental interventions attenuate myopia progression in children, but it is still unclear how this occurs or how these interventions can be improved to increase their protective effects. To optimize myopia interventions, directed mechanistic studies are needed. The mouse model is well-suited to these studies because of its well-characterized visual system and the genetic experimental tools available, which can be combined with pharmacological and environmental manipulations for powerful investigations of causation. This review describes aspects of the mouse visual system that support its use as a myopia model and presents genetic, pharmacological, and environmental studies that significantly contribute to our understanding of the mechanisms that underlie myopigenesis.

Chromatic cues for the sign of defocus in the peripheral retina

Detecting optical defocus at the retina is crucial for accurate accommodation and emmetropization. However, the optical characteristics of ocular defocus are not fully understood. To bridge this knowledge gap, we simulated polychromatic retinal image quality by considering both the monochromatic wavefront aberrations and chromatic aberrations of the eye, both in the fovea and the periphery (nasal visual field). Our study revealed two main findings: (1) chromatic and monochromatic aberrations interact to provide a signal to the retina (chromatic optical anisotropy) to discern positive from negative defocus and (2) that chromatic optical anisotropy exhibited notable differences among refractive error groups (myopes, emmetropes and hyperopes). These findings could enhance our understanding of the underlying mechanisms of defocus detection and their subsequent implications for myopia control therapies. Further research is needed to explore the retinal architecture's ability to utilize the optical signals identified in this study.

Characteristics of Peripheral Retinal Refraction and Its Role in Children with Different Refractive States

Introduction

Peripheral retinal refraction plays a crucial role in myopia, but the specific mechanism is not clear. We refined the retinal partitions to explore the characteristics of peripheral retinal refraction and its role in emmetropic, low, and moderate myopic children aged 6 to 12 years.

Methods

A total of 814 subjects (814 eyes) were enrolled in the study. The participants were divided into three groups according to the central spherical equivalent refraction (SER), which were emmetropia group (E), low myopia group (LM) and moderate myopia group (MM). Multispectral refractive topography (MRT) was used to measure the retinal absolute and relative refractive difference value (RDV) in different regions. The range was divided into superior, inferior, temporal, and nasal RDV (SRDV, IRDV, TRDV, and NRDV) on the basis of several concentric circles extending outward from the macular fovea (RDV15, RDV30, RDV45, RDV30-15, RDV45-30, and RDV-45). Kruskal-Wallis test was used to analyze the differences of peripheral refraction for all the regions among the three groups. Spearman rank correlation was performed to explore correlations between SER and RDV, axial length (AL) and RDV.

Results

The absolute value of RDV decreased with increasing degree of myopia in all regions (P < 0.01). Subjects with different refractive degrees had different relative value of RDV. In nasal position within 45° and temporal position within 30°, the peripheral retina exhibited significantly different relative hyperopic refractive status among Group E, Group LM, and Group MM (P < 0.05). SER was negatively correlated with NRDV within 30° (especially in the range of NRDV30-15) (r = -0.141, P < 0.01), positively correlated with TRDV within 15° (r = 0.080, P = 0.023), and not significantly correlated with SRDV and IRDV when the retina was divided into four parts. AL was positively correlated with NRDV within 30° (especially in the range of NRDV30-15) (r = 0.109, P = 0.002), negatively correlated with TRDV within 15° (r = -0.095, P = 0.007).

Conclusions

The peripheral defocus has significant implications for the genesis of myopia. The peripheral defocus of the horizontal direction, especially within the range of NRDV30, has greater effect on the development of myopia in children. Higher NRDV30 is associated with lower SER and longer AL.

Guidelines for preventing and slowing myopia progression in Brazilian children

This document on myopia control is derived from a compilation of medical literature and the collective clinical expertise of an expert committee comprising members from the Brazilian Society of Pediatric Ophthalmology and the Brazilian Society of Contact Lenses and Cornea. To manage myopia in children, the committee recommends corneal topography and biannual visits with cycloplegic refraction, along with annual optical biometry. For fast-progressing myopia, biannual biometry should be considered. Myopic progression is defined as an annual increase in spherical equivalent greater than 0.50 D/year or in axial length greater than 0.3 mm (until 10 years old) or 0.2 mm (above 11 years). The proposed treatments for myopia progression include environmental control, low concentration atropine, defocus glasses, contact lenses, or Ortho-K lenses, and combinations of these methods may be necessary for uncontrolled cases. Treatment should be sustained for at least 2 years. This document serves as a comprehensive guideline for diagnosing, treating, and monitoring pre-myopic and myopic children in Brazil.

Advances in the study of the influence of photoreceptors on the development of myopia

This review examines the pivotal role of photoreceptor cells in ocular refraction development, focusing on dopamine (DA) as a key neurotransmitter. Contrary to the earlier view favoring cone cells, recent studies have highlighted the substantial contributions of both rod and cone cells to the visual signaling pathways that influence ocular refractive development. Notably, rod cells appeared to play a central role. Photoreceptor cells interact intricately with circadian rhythms, color vision pathways, and other neurotransmitters, all of which are crucial for the complex mechanisms driving the development of myopia. This review emphasizes that ocular refractive development results from a coordinated interplay between diverse cell types, signaling pathways, and neurotransmitters. This perspective has significant implications for unraveling the complex mechanisms underlying myopia and aiding in the development of more effective prevention and treatment strategies.

Frequency-dependent effects of 0.05% atropine eyedrops on myopia progression and peripheral defocus: a prospective study

BACKGROUND

Atropine, specifically 0.05% eyedrops, has proven effective in slowing myopia progression. This study aims to investigate peripheral refraction (PR) characteristics in myopic children treated with 0.05% atropine eyedrops at different frequencies.

METHODS

One hundred thirty-eight myopic children completed this one-year prospective study, randomly assigned to once daily (7/7), twice per week (2/7), or once per week (1/7) groups. Spherical equivalent (SE) and axial length (AL) were measured. PR was assessed using a custom-made Hartmann-Shack wavefront peripheral sensor, covering a visual field of horizontal 60° and vertical 36°. Relative peripheral refraction (RPR) was calculated by subtracting central from peripheral measurements.

RESULTS

After one year, SE increased more significantly in the 1/7 group compared to the 7/7 group (P < 0.001) and 2/7 group (P = 0.004); AL elongation was also greater in the 1/7 group compared to the 7/7 group (P < 0.001). In comparison with higher frequency groups, 1/7 group exhibited more myopic PR in the fovea and its vertical superior, inferior, and nasal retina; and less myopic RPR in the periphery retina after one-year (P < 0.05). Additionally, RPR in the 7/7 group demonstrated myopic shift across the entire retina, the 2/7 group in temporal and inferior retina, while the 1/7 group showed a hyperopic shift in the superior retina (P < 0.05). Moreover, myopic shift of RPR in the temporal retina is related to less myopia progression, notably in the 7/7 group (P < 0.05).

CONCLUSIONS

Atropine inhibits myopia progression in a frequency-dependent manner. The once-daily group showed the slowest myopia progression but exhibited more myopic shifts in RPR. Additionally, RPR in the temporal retina was related to myopia progression in all groups.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2100043506. Registered 21 February 2021, https://www.chictr.org.cn/showproj.html?proj=122214.

Characteristics of Eyes With CRB1-Associated EOSRD/LCA: Age-Related Changes

PURPOSE

To evaluate ocular and retinal features of CRB1-associated early onset severe retinal dystrophy/Leber congenital amaurosis (EOSRD/LCA) for age-related changes.

DESIGN

Retrospective cohort study.

METHODS

Sixteen pediatric patients with biallelic CRB1 EOSRD/LCA who had been followed for up to 18 years were reviewed. Results of comprehensive ophthalmic examinations-including visual acuity, refractive error, dark-adapted visual threshold, Goldmann perimetry, and macular optical coherence tomography (OCT)-were analyzed for significant age-related changes using mixed-effects models.

RESULTS

Visual acuity dark-adapted visual sensitivity, and area of seeing visual field (all subnormal from the earliest ages recorded) declined with increasing age. Hyperopia was stable through childhood and adolescence. In CRB1 EOSRD/LCA, OCT extrafoveal inner and outer laminar thicknesses exceeded those in controls but varied little with age, and foveal metrics (depth, breadth, thickness at rim) differed significantly from those in controls, but variations in foveal metrics were not associated with declines in acuity.

CONCLUSIONS

From the youngest ages, retinal and visual function is significantly subnormal and becomes progressively compromized. A goal of future therapies should be intervention at young ages, when there is more function to be rescued.

No Evidence of an Association between Genetic Factors Affecting Response to Vitamin A Supplementation and Myopia: A Mendelian Randomization Study and Meta-Analysis

The relationship between vitamin A supplementation and myopia has been a topic of debate, with conflicting and inconclusive findings. We aimed to determine whether there is a causal relationship between vitamin A supplementation and the risk of myopia using Mendelian randomization (MR) and meta-analytical methods. Genetic variants from the UK Biobank and FinnGen studies associated with the response to vitamin A supplementation were employed as instrumental variables to evaluate the causal relationship between vitamin A supplementation and myopia. Fixed-effects meta-analysis was then used to combine MR estimates from multiple sources for each outcome. The meta-analysis of MR results found no convincing evidence to support a direct causal relationship between vitamin A supplementation and myopia risk (odds ratio (OR) = 0.99, 95% confidence interval (CI) = 0.82-1.20, I2 = 0%, p = 0.40). The analysis of three out of the four sets of MR analyses indicated no direction of causal effect, whereas the other set of results suggested that higher vitamin A supplementation was associated with a lower risk of myopia (OR = 0.002, 95% CI 1.17 × 10-6-3.099, p = 0.096). This comprehensive MR study and meta-analysis did not find valid evidence of a direct association between vitamin A supplementation and myopia. Vitamin A supplementation may not have an independent effect on myopia, but intraocular processes associated with vitamin A may indirectly contribute to its development.

Innate immune responsive inflammation in development of progressive myopia

PURPOSE

Inflammation has been implicated for development of myopia. It is not clear when inflammation is kicked in during the course of myopia, and what characteristics of the inflammation. In this study, we tested for cytokines from aqueous humour of eyes with wide spectrum of refractive status for profiling the inflammation.

METHODS

Aqueous humour of 142 patient eyes were tested for soluble intercellular adhesion molecule 1 (sICAM-1), monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta 2 (TGF-β2) using an enzyme-linked immunosorbent assay (ELISA). Eye globe axial length of these patients ranged from emmetropia to high myopia.

RESULTS

Of 142 patients, an average axial length is 25.51 ± 3.31 mm, with a range of 21.56-34.37 mm. There are 36 cases in lower 25 percentile, 37 cases in upper 25 percentile, and 69 case in the middle 50 percentile. sICAM-1 and MCP-1 were significantly higher in the eyes with staphyloma (407.48 pg/mL, 312.31 pg/mL, n = 33) or macular schisis (445.86 pg/mL,345.33 pg/mL, n = 19) than that in the eyes without these changes (206.44 pg/mL, 244.76 pg/mL, n = 107). All three cytokines level was significantly associated with eye globe axial in a positive mode while adjusting for the age and sex. Strength of the association was the greatest for sICAM-1 and the weakest for TGF- β2. MCP-1 was in between.

CONCLUSION

sICAM-1 and MCP-1 in ocular fluid may be indicative biomarkers for progressive high myopia and the underneath autoimmune inflammation. sICAM-1 may be used as a monitoring biomarker for development of pathologic myopia.

Peripheral Choroidal Response to Localized Defocus Blur: Influence of Native Peripheral Aberrations

Purpose

This study aims to examine the short-term peripheral choroidal thickness (PChT) response to signed defocus blur, both with and without native peripheral aberrations. This examination will provide insights into the role of peripheral aberration in detecting signs of defocus.

Methods

The peripheral retina (temporal 15°) of the right eye was exposed to a localized video stimulus in 11 young adults. An adaptive optics system induced 2D myopic or hyperopic defocus onto the stimulus, with or without correcting native peripheral ocular aberrations (adaptive optics [AO] or NoAO defocus conditions). Choroidal scans were captured using Heidelberg Spectralis OCT at baseline, exposure (10, 20, and 30 minutes), and recovery phases (4, 8, and 15 minutes). Neural network-based automated MATLAB segmentation program measured PChT changes from OCT scans, and statistical analysis evaluated the effects of different optical conditions over time.

Results

During the exposure phase, NoAO myopic and hyperopic defocus conditions exhibited distinct bidirectional PChT alterations, showing average thickening (10.0 ± 5.3 µm) and thinning (-9.1 ± 5.5 µm), respectively. In contrast, induced AO defocus conditions did not demonstrate a significant change from baseline. PChT recovery to baseline occurred for all conditions. The unexposed fovea did not show any significant ChT change, indicating a localized ChT response to retinal blur.

Conclusions

We discovered that the PChT response serves as a marker for detecting peripheral retinal myopic and hyperopic defocus blur, especially in the presence of peripheral aberrations. These findings highlight the significant role of peripheral oriented blur in cueing peripheral defocus sign detection.

Visual information and the development/control of myopia: Insights from nonhuman primate experiences

Over the past few decades, primarily by animal studies, correspondingly reinforced by epidemiological, clinical studies and controlled trials, researchers have identified that visual feedback regulates eye refractive developments, with visual image alterations being the most influential myopiagenic environmental factor. This article reviews studies using nonhuman primates to investigate visual risk factors for myopia development and evaluates and summarizes which visual factors contribute to the occurrence and progression of myopia. The possible underlying myopiagenic mechanisms and related myopia prevention/control strategies are also discussed.

Efficacy of Soft Contact Lenses for Myopia Control: A Systematic Review

PURPOSE

To summarize and analyze critically the scientific evidence focused on the effectiveness of the use of hydrophilic contact lenses (HCLs) in myopia control, as well as their impact on visual quality and the involvement on the accommodative and binocular function.

METHODS

This systematic review was developed selecting all original studies which evaluated HCLs for myopia control with follow-up of at least 1 year. Eligible randomized controlled trials (RCTs) were retrieved from PubMed MEDLINE and Scopus. Methodological quality of the studies was assessed using the Critical Appraisal Skills Programme (CASP) for RCTs.

RESULTS

The search provided a total of 276 articles, selecting 13 according to the inclusion and exclusion criteria. The majority of studies evaluating the effectiveness of HCL showed a good efficacy in myopia progression, providing a good quality of vision. The quality of these studies was found to be suitable according to the CASP tool. The accommodative and binocular function with these lenses was evaluated in few studies, reporting a trend to an increase in the accommodative response and exophoria in near vision, while maintaining good level of stereopsis. Aberrometry and pupillometry were only studied in one trial, in which the authors did not find changes in these variables after the use of a myopia control HCL.

CONCLUSIONS

There is a strong evidence about the effectiveness of different HCLs designs for slowing down myopia progression in children, providing all of them good levels of visual quality. However, there is still poor evidence about changes in accommodation and binocular function, as well as in pupil size and aberrometry with myopia control HCLs, being necessary more studies focused on this issue.

Impact of pupil and defocus ring intersection area on retinal defocus

PURPOSE

With the rising prevalence of myopia, especially among the young, orthokeratology (Ortho-K) stands out as a promising approach, not only to reduce myopia but also to control the progression of axial length (AL). This study examined how the intersection area between the pupil and defocus ring influenced retinal defocus and axial growth after Ortho-K.

METHODS

A case-control study was conducted with 100 participants (100 eyes). Both AL and the refraction difference value (RDV), that is, the peripheral refractive error measured with respect to the central value after wearing Ortho-K lenses, were determined. Subjects were categorised into two groups based on the size of the intersection area after 3 months of lens wear: Group A (<4.58 mm2 ) and Group B (≥4.58 mm2 ).

RESULTS

Group B demonstrated significantly lower changes in AL and RDV at 30-40° and 40-53° compared with Group A after 3 months of lens wear (all p < 0.05). After 6 months of lens wear, Group B showed significantly lower changes in AL and RDV in the 40-53° region compared with Group A (all p < 0.05). Correlation analysis revealed that as the intersection area increased, the changes in AL and RDV at 0-53°, 30-40° and 40-53° eccentricity decreased after both 3 and 6 months of lens wear (all p < 0.01).

CONCLUSIONS

A larger intersection area between the pupil and defocus ring within a certain time period can cause a greater amount of myopic defocus at 30-53° from the fovea. The results suggest that a larger intersection area might lead to more effective control of axial growth.

The effect of multifocal contact lenses on the dynamic accommodation step response

PURPOSE

To measure the dynamic accommodation response (AR) to step stimuli with and without multifocal contact lenses (MFCLs), in emmetropes and myopes.

METHODS

Twenty-two adult subjects viewed alternating distance (0.25D) and near (3D) Maltese crosses placed in free space, through two contact lens types: single vision (SVCL) or centre-distance multifocal (MFCL; +2.50D add). The AR level was measured along with near to far (N-F) and far to near (F-N) step response characteristics: percentage of correct responses, magnitude, latency, peak velocity and duration of step response.

RESULTS

There was no difference between N-F and F-N responses, or between refractive groups in any aspect of the accommodation step response dynamics. The percentage of correct responses was unaffected by contact lens type. Through MFCLs, subjects demonstrated smaller magnitude, longer latency, shorter duration and slower peak velocity steps than through SVCLs. When viewing the near target, the AR through MFCLs was significantly lower than through SVCLs. When viewing the distance target with the MFCL, the focal points from rays travelling through the distance and near zones were approximately 0.004D behind and 2.50D in front of the retina, respectively. When viewing the near target, the respective values were approximately 1.89D behind and 0.61D in front of the retina.

CONCLUSION

The defocus error required for accommodation control appears not to be solely derived from the distance zone of the MFCL. This results in reduced performance in response to abruptly changing vergence stimuli; however, these errors were small and unlikely to impact everyday visual tasks. There was a decrease in ocular accommodation during near tasks, which has previously been correlated with a reduced myopic treatment response through these lenses. With MFCLs, the estimated dioptric myopic defocus was the largest when viewing a distant stimulus, supporting the hypothesis that the outdoors provides a beneficial visual environment to reduce myopia progression.

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.

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.

Optical interventions for myopia control

A range of optical interventions have been developed to slow the progression of myopia. This review summarizes key studies and their outcomes. Peer-reviewed, randomized controlled clinical trials of at least 18 months duration were identified. Randomized clinical trials were identified and summarised: 13 for spectacles, 5 for overnight orthokeratology, 5 for soft contact lenses, and 3 for orthokeratology combined with low concentration atropine. Overnight orthokeratology trials were the most consistent with 2-year slowing of axial elongation between 0.24 and 0.32 mm. Other modalities were more variable due to the wide range of optical designs. Among spectacle interventions, progressive addition lenses were the least effective, slowing axial elongation and myopia progression by no more than 0.11 mm and 0.31 D, respectively. In contrast, novel designs with peripheral lenslets slow 2-year elongation and progression by up to 0.35 mm and 0.80 D. Among soft contact lens interventions, medium add concentric bifocals slow 3-year elongation and progression by only 0.07 mm and 0.16 D, while a dual-focus design slows 3-year elongation and progression by 0.28 mm and 0.67 D. In summary, all three optical interventions have the potential to significantly slow myopia progression. Quality of vision is largely unaffected, and safety is satisfactory. Areas of uncertainty include the potential for post-treatment acceleration of progression and the benefit of adding atropine to optical interventions.

Intraocular cetuximab: Safety and effect on axial elongation in young Guinea pigs with lens-induced myopization

This study aimed to examine the intraocular tolerability of the epidermal growth factor receptor antibody cetuximab, when applied intravitreally, and its effect on axial elongation. Guinea pigs aged 2-3 weeks were subjected to bilateral plano glasses and bilateral lens-induced myopization (LIM) as a single procedure for group I (n = 8) and group II (n = 8), respectively. In the animals of group III (n = 8), group IV (n = 8), and group V (n = 8), the right eyes of the animals, in addition to LIM, received four weekly intravitreal injections of cetuximab (Erbitux®) in doses of 6.25 μg, 12.5 μg, and 25 μg, respectively. As controls, the left eyes, in addition to LIM, received corresponding intraocular injections of phosphate-buffered saline. The animals underwent regular ophthalmoscopic examinations and biometry for axial length measurements. With increasing doses of cetuximab, the inter-eye difference in axial elongation (at study end, left eyes minus right eyes) were significantly the smallest in group I (0.00 ± 0.02 mm) and group II (-0.01 ± 0.02 mm), they were larger in group III (0.04 ± 0.04 mm) and group IV (0.10 ± 0.03 mm), and they were the largest in group V (0.11 ± 0.01 mm). The inter-eye difference in axial elongation enlarged (P < 0.001) with the number of injections applied. Retinal thickness at the posterior pole (right eyes) was significantly thicker in group V than in group II (P < 0.01). The density of apoptotic cells (visualized by TUNEL-staining) did not vary significantly between any of the groups (all P > 0.05). The results suggest that intravitreal injections of cetuximab in young guinea pigs with LIM resulted in a reduction in axial elongation in a dose-dependent and number of treatment-dependent manner. Intraocular toxic effects, such as intraocular inflammation, retinal thinning, or an increased density of apoptotic cells in the retina, were not observed in association with the intravitreally applied cetuximab.

Eye Size and Shape in Relation to Refractive Error in Children: A Magnetic Resonance Imaging Study

Purpose

The purpose of this study was to determine the association between eye shape and volume measured with magnetic resonance imaging (MRI) and optical biometry and with spherical equivalent (SE) in children.

Methods

For this study, there were 3637 10-year-old children from a population-based birth-cohort study that underwent optical biometry (IOL-master 500) and T2-weighted MRI scanning (height, width, and volume). Cycloplegic refractive error was determined by automated refraction. The MRI images of the eyes were segmented using an automated algorithm combining atlas registration with voxel classification. Associations among optical biometry, anthropometry, MRI measurements, and RE were tested using Pearson correlation. Differences between refractive error groups were tested using ANOVA.

Results

The mean volume of the posterior segment was 6350 (±680) mm3. Myopic eyes (SE ≤ -0.5 diopters [D]) had 470 mm3 (P < 0.001) and 970 mm3 (P < 0.001) larger posterior segment volume than emmetropic and hyperopic eyes (SE ≥ +2.0D), respectively. The majority of eyes (77.1%) had an oblate shape, but 47.4% of myopic eyes had a prolate shape versus 3.9% of hyperopic eyes. The correlation between SE and MRI-derived posterior segment length (r -0.51, P < 0.001) was stronger than the correlation with height (r -0.30, P < 0.001) or width of the eye (r -0.10, P < 0.001).

Conclusions

In this study, eye shape at 10 years of age was predominantly oblate, even in eyes with myopia. Of all MRI measurements, posterior segment length was most prominently associated with SE. Whether eye shape predicts future myopia development or progression should be investigated in longitudinal studies.

Efficiency and Related Factors of Multifocal Soft Contact Lenses in Controlling Myopia

OBJECTIVE

To evaluate ocular changes in Chinese myopic children wearing multifocal soft contact lenses and explore their efficiency and related factors.

METHOD

This was a prospective, double-blind, randomized controlled study. A total of 36 myopic children aged 7 to 12 years were randomly divided into groups wearing multifocal soft contact lenses (MFCLs) or single-vision soft contact lenses (SVCLs) and followed up for 12 months. The spherical equivalent (SE), axial length (AL), choroidal thickness, and vascularity were measured before commencement and after 6 and 12 months of lens wear. Correlation between ocular changes and myopia progression was determined.

RESULTS

A total of 32 subjects (6 males and 26 females) completed the study and were included in the analysis. After 12 months of lens wear, both the AL elongation (0.25±0.22 vs. 0.43±0.16 mm, P=0.011) and the SE progression (-0.69±0.69 D vs. -1.45±0.56 D, P=0.002) of the MFCL group were significantly lower than those of the SVCL group. After 12 months, the progression of myopia was significantly correlated with changes of the choroid in the MFCL wearers, whereas no such correlation was observed in the SVCL group.

CONCLUSION

Multifocal soft contact lens can slow myopia progression, and this effect may be related to the changes of the choroid.

Characteristics of ciliary muscle profile in high myopes measured by swept-source anterior segment optical coherence tomography

OBJECTIVE

To characterize and compare the ciliary muscle thickness (CMT) between low and high myopes using swept-source anterior segment optical coherence tomography (AS-OCT).

METHODS

Forty visually healthy young Chinese adults aged 18-25 years were divided into two groups based on refractive errors: low myopia (n = 20, spherical-equivalent refractive error (SER) between -0.50 D to -3.00 D) and high myopia (n = 20, SER ≤ -6.00 D). Cycloplegic refractions were performed before axial length (AL) and CMT were measured using a partial coherence laser interferometer and an AS-OCT respectively. CMT was measured perpendicularly to the sclera-ciliary muscle interface at 1 mm (CMT_1), 2 mm (CMT_2), and 3 mm (CMT_3) posterior to the scleral spur, and at the location with maximal thickness (CMT_MAX).

RESULTS

High myopes demonstrated thicker CMT at 2 mm (CMT_2, p = 0.035) and 3 mm (CMT_3, p = 0.003) posterior to the scleral spur, but thinner maximal CMT (CMT_MAX, p = 0.005) than low myopes. The apical CMT_1 and CMT_MAX were also thinner in high myopes than in low myopes (both p< 0.001). CMT_MAX, apical CMT_1, and apical CMT_MAX correlated directly with SER and inversely with AL; in contrast, CMT_2 and CMT_3 showed inverse correlations with SER but direct correlations with AL.

CONCLUSION

Our findings revealed significant differences in CMT between low and high myopes, with high myopes showing thicker CMT at 2 mm and 3 mm posterior to the scleral spur, but thinner maximal CMT. These results provide new evidence of the potential structural differences in ciliary muscles during myopia development and progression.

Effect of wearing peripheral focus-out glasses on emmetropization in Chinese children aged 6-8 years: study protocol for a 2-year randomized controlled intervention trial

BACKGROUND

Myopia is one of the most common eye diseases causing visual impairment and blindness, and the high prevalence in adolescents remains a major public health concern. Based on clinical studies using optical defocus to regulate ocular growth and refractive changes through visual feedback, we hypothesize that early wearing of peripheral myopic defocusing spectacles in children with high risk of myopia may slow the process of emmetropization and even prevent the onset of myopia by inducing more peripheral myopic defocus. The aim of this study is to investigate whether the wearing of peripheral focus-out glasses can be effective in delaying emmetropization in non-myopic children aged 6-8 years.

METHODS

The study is a 2-year randomized controlled trial. A total of 160 subjects will be randomized into the experimental group or the control group. The experimental group will be fitted with direct emmetropia with focus-out glasses (DEFOG) to guide the emmetropization process. The control group will not receive any treatment and will serve as a blank control group. The primary aim is to determine whether non-myopic children wearing DEFOG lenses are superior to those who do not receive any intervention on the progression of cycloplegic objective refraction over 2 years.

DISCUSSION

This is the first randomized controlled trial aiming at myopic prevention by non-invasive intervention in non-myopic children. This study aims to initially investigate whether wearing peripheral focus-out glasses can effectively delay the process of emmetropization in children aged 6-8 years with high risk of myopia, which might give potential clues for further exploration on early prevention of myopia.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05689567. Registered on 10 January 2023.

Myopia prevention and control in children: a systematic review and network meta-analysis

OBJECTIVES

To analyse and compare the efficacy of different interventions for myopia prevention and control in children.

METHODS

We searched CNKI, VIP, Wan-Fang, CBM, Chinese Clinical Registry, PubMed, The Cochrane Library, Web of Science, Embase and ClinicalTrials.gov from inception to July 2022. We selected randomized controlled trials (RCTs) that included interventions to slow myopia progression in children. The main outcomes included mean annual change in axial length (AL) (millimetres/year) and in refraction (R) (dioptres/year).

RESULTS

A total of 80 RCTs (27103 eyes) were included. In comparison with control, orthokeratology (AL, -0.36 [-0.53, -0.20], P < 0.05; R, 0.56 [0.34, 0.77], P < 0.05), 1%Atropine (AL, -0.39 [-0.65, -0.13], P < 0.05; R, 0.54 [0.31, 0.77], P < 0.05), 0.01%Atropine + orthokeratology (AL, -0.47 [-0.80, -0.14], P < 0.05; R, 0.81 [0.43, 1.20], P < 0.05) could significantly slow the progression of myopia; in addition, progressive multi-focal spectacle lenses (PMSL) (0.42, [0.06, 0.79], P < 0.05), bifocal soft contact lenses (0.40, [0.03, 0.77], P < 0.05), 0.5%Atropine (0.67 [0.25, 1.10], P < 0.05), 0.1%Atropine (0.42 [0.15, 0.71], P < 0.05), 0.05%Atropine (0.57 [0.28, 0.86], P < 0.05), 0.01%Atropine (0.33 [0.15, 0.52], P < 0.05), 1%Atropine + bifocal spectacle lenses (BSL) (1.30 [0.54, 2.00], P < 0.05), 1%Atropine + PMSL (0.66 [0.23, 1.10], P < 0.05), 0.01%Atropine + single vision spectacle lenses (SVSL) (0.70 [0.23, 1.10], P < 0.05), 0.01%Atropine + orthokeratology (0.81 [0.43, 1.20], P < 0.05), BSL + Massage (0.85 [0.22, 1.50], P < 0.05), SVSL + Red light (0.59 [0.06, 0.79], P < 0.05) showed significant slowing effect on the increase in R.

CONCLUSIONS

This network meta-analysis suggests that the combined measures were most effective in AL and R, followed by Atropine.

Relationship between myopia control and amount of corneal refractive change after orthokeratology lens treatment

BACKGROUND

To evaluate the relationship between amount of corneal refractive change (CRC) after wearing orthokeratology (Ortho-K) lenses and axial length (AL) growth.

METHODS

We retrospectively enrolled 77 patients (77 eyes) aged 8-14 years who wore Ortho-K lenses more than 12 months. We divided the patients into 2 subgroups: spherical equivalent (SE) ≤ -3.0 D and SE > -3.0 D subgroup. The sagittal and tangential curvature maps and corneal topographic data within the 8-mm diameter ring at the baseline and during follow-up visits after wearing Ortho-K lens were recorded in addition to the area, height, and volume of the CRC region. The AL data were recorded at the baseline and during follow-up visits. Multivariate linear regression was conducted to analyze associations between the area, height, and volume of the CRC region, AL elongation, and SE.

RESULTS

The average change in the CRC region was 9.77 ± 0.60 D in height, 16.66 ± 3.61 mm2 in area, and 87.47 ± 8.96 D*mm2 in volume on the tangential diagram after wearing Ortho-K lenses for 3 months. The AL showed a change of 0.19 ± 0.14 mm after 1 year of Ortho-K lens wear (P < 0.05). At 1 year, AL elongation was negatively correlated with the area (P = 0.019) and volume (P < 0.001) of the CRC region. At 1 year, for every 1-mm2 increase in the area and every 1-D*mm2 increase in the volume of the CRC region, the average AL elongation decreased by 0.01 mm and 0.002 mm, respectively, in the multivariate analysis. In patients with SE ≤ -3.0 D, AL elongation was negatively correlated with the CRC-region volume (β = -0.002, P = 0.018), and in patients with SE > -3.0 D, AL elongation was negatively correlated with the CRC-region area (β = -0.017, P = 0.016).

CONCLUSIONS

The AL elongation-control efficacy of Ortho-K lenses may be related to the area and volume of the CRC region.

Changes in relative peripheral refraction and optical quality in Chinese myopic patients after small incision lenticule extraction surgery

PURPOSE

To observe changes in retinal refraction difference values (RDV) and aberrations after small incision lenticule extraction (SMILE) surgery and evaluate their correlations.

METHODS

This study recruited 112 patients (112 eyes) who underwent SMILE for myopia. Participants were classified into the Low and Moderate Myopia group (LM, -0.50 to -6.0 D) and High Myopia group (HM, >-6.0 D) according to the central spherical equivalent (SE). RDVs in the five retinal eccentricities from 0° to 10°, 10° to 20°, 20° to 30°, 30° to 40°, and 40° to 53° are recorded as RDV-(0-10), RDV-(10-20), RDV-(20-30), RDV-(30-40), and RDV-(40-53), respectively; additionally, RDVs have four sectors, i.e., RDV-Superior (RDV-S), RDV-Inferior (RDV-I), RDV-Temporal (RDV-T), and RDV-Nasal (RDV-N). With a 3-month follow-up, changes in RDV (ΔRDV) and changes in aberrations [Δtrefoil, Δcoma, Δspherical aberration (SA), and Δtotal higher-order aberrations (HOA)] after surgery were recorded.

RESULTS

No significant differences were observed in total RDV (TRDV), RDV-(0-53), RDV-S, RDV-I, RDV-N, trefoil, coma, and SA between the two groups before SMILE surgery. However, after SMILE, hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, RDV-T, and RDV-N] in the LM group and hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, and RDV-N] in the HM group were significantly lower at 3 months postoperatively than preoperatively, and the RDV-(40-53), RDV-S, and RDV-N were lower in the HM group than in the LM group. Aberrations [trefoil (vertical), coma, and HOA] in the LM group and aberrations (trefoil, coma, SA, and HOA) in the HM group were significantly higher at 3 months postoperatively than preoperatively, and the coma, trefoil(horizontal), SA, and HOA were higher in the HM group than in the LM group. In the multivariate analysis, ΔRDV-(40-53) was significantly correlated with ΔSA, and ΔRDV-T and ΔRDV-N were significantly correlated with Δcoma (horizontal).

CONCLUSIONS

Our findings suggest that SMILE reduces retinal peripheral hyperopic defocus but introduces some higher-order aberrations, especially in people with high myopia refractive errors.

Two-Dimensional Peripheral Refraction and Higher-Order Wavefront Aberrations Induced by Orthokeratology Lenses Decentration

Purpose

The purpose of this study was to explore two-dimensional peripheral refraction and higher-order aberrations (HOAs) induced by orthokeratology lens decentration.

Methods

Two-dimensional peripheral refraction and HOAs in a rectangular field (horizontally 60 degrees and vertically 36 degrees) were obtained using an open-view Hartmann-Shack wavefront sensor. The peripheral field was divided into 8 regions according to a combination of superior (UZ) or inferior (LZ) and a value, 1 (T25 to T30), 2 (T20 to T25), 3 (N20 to N25), or 4 (N25 to N30). The decentration of the lens was evaluated based on the change of power in the front of the tangential corneal map. All measurements were taken at the baseline and 1 month after lens fitting.

Results

In total, 134 myopic children (age = 12.47 ± 1.70 years, SER = -2.44 ± 1.10 diopters [D]) were recruited. In general, horizontally asymmetrical change was observed in relative peripheral refraction (RPR), spherical aberration (SA), and horizontal coma. The root-mean square of higher order aberration (RMSHOA) and vertical coma demonstrated radial symmetrical change and vertically asymmetric change, respectively. Relative peripheral myopia was significantly increased after the treatment, with more myopic refraction in the temporal side. RPR changes in UZ2, UZ3, UZ4, LZ1, and LZ2 were related to the amount of lens decentration (r ≈ 0.4, P < 0.05). All HOAs increased after lens fitting (around 0.03 um, 0.02 um, 0.04 um, and 0.41 um for SA, horizontal COMA, vertical COMA, and RMSHOA in the periphery region).

Conclusions

RPR and HOAs are related to lens decentration, which might contribute to the efficacy of orthokeratology.

Translational Relevance

The study found a decentration-related optical feature after 1 month of lens wear, which is a suggested protective factor in myopia treatment. The findings might provide new insights for customized contact lens myopia treatment based on optics.

Single-cell RNA sequencing of retina revealed novel transcriptional landscape in high myopia and underlying cell-type-specific mechanisms

High myopia is a leading cause of blindness worldwide with increasing prevalence. Retina percepts visual information and triggers myopia development, but the underlying etiology is not fully understood because of cellular heterogeneity. In this study, single-cell RNA sequencing analysis was performed on retinas of mouse highly myopic and control eyes to dissect the involvement of each cell type during high myopia progression. For highly myopic photoreceptors, Hk2 inhibition underlying metabolic remodeling from aerobic glycolysis toward oxidative phosphorylation and excessive oxidative stress was identified. Importantly, a novel Apoe + rod subpopulation was specifically identified in highly myopic retina. In retinal neurons of highly myopic eyes, neurodegeneration was generally discovered, and the imbalanced ON/OFF signaling driven by cone-bipolar cells and the downregulated dopamine receptors in amacrine cells were among the most predominant findings, indicating the aberrant light processing in highly myopic eyes. Besides, microglia exhibited elevated expression of cytokines and TGF-β receptors, suggesting enhanced responses to inflammation and the growth-promoting states involved in high myopia progression. Furthermore, cell-cell communication network revealed attenuated neuronal interactions and increased glial/vascular interactions in highly myopic retinas. In conclusion, this study outlines the transcriptional landscape of highly myopic retina, providing novel insights into high myopia development and prevention.

The effect of sustained eye rotation upon eye length in healthy myopic adults

AIM

The aim of the study was to determine whether ocular movement can affect the shape of the globe and lead to measurable change in axial and peripheral eye length.

METHODS

Ten subjects aged 18-30 years (6 M/4 F) participated with informed consent. The mean spherical equivalent refractive error was ≤-1.00 DS with cylindrical refraction <-1.25 DC. One drop of tropicamide hydrochloride 1% was instilled 20 min before measurement to induce mydriasis and mild cycloplegia. Using IOLMaster, eye length was measured centrally and temporally (25° off-axis) in four different positions. Subjects then rotated their eyes 25° in the temporal direction to fixate on a target for 10 min. After that, the same measurements were repeated.

RESULTS

Before rotation, the group mean peripheral eye length was significantly shorter than the central eye length (P < 0.05). There was no significant variation in central or peripheral eye length due to off-axis fixation, either after the initial eye rotation or after fixation for 10 min at the off-axis point. The difference between central and peripheral eye lengths was maintained after 10 min of temporal fixation (P < 0.05).

CONCLUSION

Peripheral eye length was shorter than central eye length showing the prolate shape associated with myopia. The action of the extraocular muscles on the globe has no significant effect upon the retinal shape assessed by off-axis eye length measurement in myopic subjects.

Myopia: Histology, clinical features, and potential implications for the etiology of axial elongation

Myopic axial elongation is associated with various non-pathological changes. These include a decrease in photoreceptor cell and retinal pigment epithelium (RPE) cell density and retinal layer thickness, mainly in the retro-equatorial to equatorial regions; choroidal and scleral thinning pronounced at the posterior pole and least marked at the ora serrata; and a shift in Bruch's membrane opening (BMO) occurring in moderately myopic eyes and typically in the temporal/inferior direction. The BMO shift leads to an overhang of Bruch's membrane (BM) into the nasal intrapapillary compartment and BM absence in the temporal region (i.e., parapapillary gamma zone), optic disc ovalization due to shortening of the ophthalmoscopically visible horizontal disc diameter, fovea-optic disc distance elongation, reduction in angle kappa, and straightening/stretching of the papillomacular retinal blood vessels and retinal nerve fibers. Highly myopic eyes additionally show an enlargement of all layers of the optic nerve canal, elongation and thinning of the lamina cribrosa, peripapillary scleral flange (i.e., parapapillary delta zone) and peripapillary choroidal border tissue, and development of circular parapapillary beta, gamma, and delta zone. Pathological features of high myopia include development of macular linear RPE defects (lacquer cracks), which widen to round RPE defects (patchy atrophies) with central BM defects, macular neovascularization, myopic macular retinoschisis, and glaucomatous/glaucoma-like and non-glaucomatous optic neuropathy. BM thickness is unrelated to axial length. Including the change in eye shape from a sphere in emmetropia to a prolate (rotational) ellipsoid in myopia, the features may be explained by a primary BM enlargement in the retro-equatorial/equatorial region leading to axial elongation.

Factors influencing treatment zone size in orthokeratology

PURPOSE

The aim of this study was to analyze the influence of corneal topography, contact lens parameters and degree of myopia on the treatment zone (TZ) and peripheral plus ring (PPR) size in orthokeratology.

METHODS

In this retrospective study the topographic zones of the right eyes of 106 patients (73 female, 22.16 ± 8.96 years) were analyzed in the tangential difference map of the Oculus Keratograph 5M (Oculus, Wetzlar, Germany). Using the MB-Ruler Pro 5.4 software (MB-Softwaresolutions, Iffezheim, Germany) the horizontal, vertical, longest, shortest diameters and area of the TZ; horizontal, vertical, total diameters and width of the PPR were measured. Correlations were determined between these zones and the subjects' baseline parameters (myopia; corneal diameter, radii, astigmatism, eccentricity, sagittal height; contact lens radii, toricity and total diameter) for three back optic zone diameter (BOZD) groups (5.5, 6.0 and 6.6 mm). A stepwise linear regression analysis was performed to test for TZ and PPR predictability.

RESULTS

In the group of BOZD 6.0 correlations were found between the amount of myopia and the short TZ diameter (r = -0.25, p = 0.025); the steep corneal radius and the vertical diameter (r = -0.244, p = 0.029), the longest diameter (r = -0.254, p = 0.023) and the area (r = -0.228, p = 0.042) of the TZ; the amount of astigmatism and PPR width (r = 0.266, p = 0.017); eccentricity of the steep corneal meridian and PPR width (r = -0.222, p = 0.047). BOZD correlated significantly positively with all zones (p < 0.05). The best prediction model (R2 = 0.389) resulted with the TZ area as the outcome variable.

CONCLUSION

The amount of myopia, topography and contact lens parameters influence TZ and PPR in orthokeratology. Describing the TZ by its area may provide the most accurate representation of its size.