Peripheral Defocus and Myopia Management: A Mini-Review

Effect of repeated Low-Level red light therapy on axial length in myopic individuals: predictors for a good response

PURPOSE

This study aimed to investigate the effects of Repeated Low-Level Red Light (RLRL) therapy on axial length (AL) in myopic individuals and to identify key predictors for a good response to the treatment, with a focus on baseline ocular characteristics and treatment compliance.

METHODS

A total of 91 participants were enrolled, with 50 classified in the poor responders' group and 41 in the good responders' group. Baseline characteristics, including age, gender, pupil constriction diameter (PCD), intraocular pressure (IOP), spherical equivalent refraction (SER), AL, corneal curvature (ACC), and choroidal thickness (CT) were recorded. Compliance and AL changes were tracked over one year. Univariable and multivariable analyses identified factors associated with AL changes.

RESULTS

Good responders' group showed a significant AL reduction (-0.29 ± 0.16 mm, p < 0.001), while poor responders' group had an increase (+ 0.23 ± 0.12 mm, p < 0.001). Good responders' group had lower initial SER (-4.15 ± 2.87 D vs. -2.62 ± 1.80 D, p = 0.004) and longer AL (24.76 ± 1.21 mm vs. 24.15 ± 0.99 mm, p = 0.010). Both groups showed CT changes (p < 0.001), with greater increases in good responders. Univariable analysis identified initial AL and SER as predictors of a good response (both p < 0.001). Compliance showed a trend toward significance in multivariable analysis (β = -0.196, p = 0.052).

CONCLUSION

Longer baseline AL and lower SER are key predictors of a good response to RLRL therapy. Moreover, treatment compliance showed a trend toward significance, emphasizing its crucial role in achieving optimal outcomes.

Efficacy and factors influencing toric orthokeratology lenses in managing moderate to high astigmatic myopia

SIGNIFICANCE

Toric orthokeratology lenses show potential in slowing myopia progression in adolescents with moderate to high astigmatic myopia. These findings support the broader application of toric orthokeratology in managing challenging refractive conditions and mitigating myopia-related complications.

PURPOSE

This study seeks to probe the efficacy of toric orthokeratology lenses in controlling moderate to high astigmatic myopia in adolescents and to analyze the risk factors influencing treatment outcomes.

METHODS

One hundred adolescent patients with moderate to high astigmatic myopia who were treated at our medical facility from January 2022 to January 2023 were randomly selected as the study subjects. All patients were allocated to either the experimental group (n = 50) or the control group (n = 50) using a random number table method. The control group was subjected to treatment with spherical orthokeratology lenses, whereas the experimental group was treated with toric orthokeratology lenses. Changes in uncorrected visual acuity, axial length, cylinder diopters, sphere diopters, and average corneal curvature before treatment and after 12 months of treatment were compared between the two groups. The logistic regression analysis was conducted to identify the factors influencing the efficacy of toric orthokeratology lenses in controlling moderate to high astigmatic myopia in adolescents.

RESULTS

Both cohorts showed substantial improvements in uncorrected visual acuity, axial length, sphere, and average corneal curvature compared with their pre-treatment values, with the experimental cohort showing greater improvements than the control cohort (p=0.01, 0.03, 0.00, 0.00). There were no significant differences in cylinder between the two groups after treatment (p=0.56). Univariate analysis unraveled significant differences in age, baseline sphere, average corneal E value, baseline axial length, and central corneal thickness (p=0.00, 0.03, 0.04, 0.02, 0.05). Receiver operating characteristic curve analysis displayed that the area under the curve for the logistic regression model attained 0.82, with a 95% confidence interval of (0.69, 0.95), sensitivity of 88%, specificity of 72%, and a Youden index of 0.61.

CONCLUSIONS

Toric orthokeratology lenses demonstrate potential efficacy for adolescents with moderate to high astigmatic myopia by slowing myopia progression. Patients who are older, severely nearsighted, and have longer baseline axial length experience more significant control over myopia progression.

Myopia control efficacy of Asymmetric Multi-point Defocus Technique spectacle lenses: 1-year double-masked randomized controlled trial

PURPOSE

To evaluate the 12-month myopia control efficacy of an Asymmetric Multi-point Defocus Technique (AMDT) spectacle lens.

DESIGN

Double-masked randomized controlled trial.

PARTICIPANTS

140 participants completed all visits (mean age, 10.6 ± 1.5 years; 50% female), with SER between -5.00 and -0.75 diopter (D), astigmatism ≤ 1.50 D and anisometropia ≤ 1.50 D.

METHODS

144 children recruited from two ophthalmic centers aged 8-13 years with myopia of -0.75 D to -5.00 D were randomized (1:1) to wear AMDT or single vision (SVL) spectacle lenses. Cycloplegic spherical equivalent refraction (SER) and axial length (AL) were measured at the baseline, 6-month, and 12-month visits. Adaptation and visual performance questionnaires were administered during the intervention.

MAIN OUTCOME MEASURES

The SER change after one year was the primary outcome and the change in AL, visual performance, and ocular parameters after one year were defined as secondary outcomes.

RESULTS

After 12 months, the SVL group (n = 69) exhibited mean changes in SER and AL of -0.50 ± 0.06 D and 0.32 ± 0.02 mm, respectively, compared to -0.16 ± 0.06 D and 0.17 ± 0.02 mm (both p< 0.001) in the AMDT group (n = 71). Compared with the SVL group, participants in the AMDT group had significantly less myopia progression by 0.39 D in SER (74%) and 0.17mm in AL (51%) after adjustment for baseline age, baseline SER/AL and ophthalmic center. The correlation between younger age and more rapid AL elongation was more pronounced in the SVL group (r = -0.68, p <0.001), compared to the AMDT group (r = -0.37, p = 0.002). 30 (42.2%) participants in the AMDT group displayed no SER progression after 1-year. No serious adverse events or persistent visual discomfort were observed.

CONCLUSION

Compared with SVL, AMDT spectacle lenses significantly reduced SER and AL progression over 1 year, with a favorable safety profile and visual performance. The correlation between age and myopia progression was diminished after AMDT intervention, but not for SVL.

Myopi-X lenses vs. low-dose atropine in myopia control: a Turkish retrospective study : Study design: retrospective observational study

BACKGROUND

The global prevalence of myopia is rising rapidly, with projections indicating that by 2050, half of the world's population will be affected. High myopia is associated with an increased risk of sight-threatening complications, contributing to a substantial public health burden. Atropine 0.01% has been widely used for myopia control in non-Asian populations, supported by evidence demonstrating its efficacy. Myopi-X® lenses, designed to induce myopic defocus, represent an optical alternative to pharmacological intervention. Given that atropine requires monthly preparation, long-term adherence, and may cause mild side effects, (Myopi-X® Novax®) lenses offer a non-pharmacological option that may be preferable for some patients. This study compares the effectiveness of these two treatment strategies in comparison with single vision lenses to provide further insights into their role in myopia management.

METHODS

This retrospective observational study was conducted at Acıbadem Hospital, Ankara, between September 2022 and September 2023. A total of 128 patients aged 5 to 16 years with myopia were included and divided into three groups: peripheral progressive addition lenses (Myopi-X® Novax®), atropine 0.01%, and single vision lenses. Baseline characteristics, including age, gender, and axial length, were recorded. Cycloplegic autorefraction and axial length measurements were performed, and statistical analyses were conducted to assess changes in spherical equivalent refraction and axial length over 12 months. Additionally, the potential effects of baseline axial length, gender, and age group on spherical equivalent progression and axial length elongation were evaluated.

RESULTS

Significant differences were observed among the treatment groups in changes in spherical equivalent refraction and axial length (p < 0.001). Both the Myopi-X® lenses and atropine 0.01% groups exhibited significantly less myopia progression compared to the single vision lenses group (p < 0.001 for both). However, no significant difference was observed between the Myopi-X® lenses and atropine 0.01% groups at 12 months (p = 0.79), and axial length changes remained comparable between these two groups (p = 0.76). Regarding potential confounding factors, age had a significant effect on spherical equivalent refraction progression, with older children experiencing less myopic progression (p = 0.02), whereas no significant effect was observed on axial length change (p = 0.11). Gender was not significantly associated with changes in spherical equivalent (p = 0.21) or axial length (p = 0.32). Similarly, baseline axial length showed no significant association with changes in spherical equivalent (p = 0.17) or axial length (p = 0.36).

CONCLUSION

Both Myopi-X® lenses and atropine 0.01% effectively slowed myopia progression over 12 months compared to single vision lenses. Spherical equivalent progression and axial length elongation were comparable between these two treatment groups. Gender and baseline axial length did not significantly affect the outcomes, whereas older children exhibited less myopic progression in terms of spherical equivalent change. This study aimed to compare the clinical effectiveness of these two treatment strategies. Further studies with longer follow-up periods are required to evaluate the long-term sustainability of these effects.

Do myopia control spectacle lenses with defocus incorporated multiple segments technology alter visual parameters and cortical activity?

PURPOSE

This study evaluated visual parameters and cortical activity after wearing myopia control spectacle lenses with defocus incorporated multiple segments (DIMS).

METHODS

Myopic adults between 20 and 30 years of age were enrolled. The study consisted of (1) examination of visual parameters and (2) measurement of cortical responses, while wearing single vision lenses (SVL) and MiYOSMART (MS) lenses in counterbalanced order after a two-week adaptation period. Visual parameters tested were: high-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA), contrast sensitivity, heterophoria, near point of convergence (NPC), stereopsis, accommodative facility and the accommodative response. Cortical responses were assessed by visual evoked potentials (VEPs), recorded from 10 electrodes placed over the parieto-occipital area.

RESULTS

MiYOSMART lenses produced slightly better HCVA than SVL (-0.25 vs. -0.21 logMAR, p = 0.02) and a larger accommodative response (MS 1.68 D; SVL 1.53 D, p < 0.001). No significant differences in LCVA, heterophoria, NPC, stereopsis or contrast sensitivity were observed. The latencies and amplitudes of the early and late components of the VEPs (C1, N1, P1, P2) did not differ significantly between lenses.

CONCLUSIONS

This study found no clinically significant differences in visual parameters or visual cortex responses between SVL and MS lenses after 2 weeks of adaptation. These results confirm the absence of adverse visual effects from DIMS lenses for myopia control.

Advances in the study of ARR3 in myopia

The ARR3 gene (cone arrestin, OMIM: 301770) has gained significant attention as a pivotal factor in the etiology of myopia, particularly early-onset high myopia (eoHM). As a member of the arrestin gene family, ARR3 is predominantly expressed in cone photoreceptors, playing a crucial role in visual processing. Recent studies have identified specific mutations in ARR3 that correlate with an elevated risk of myopia development, highlighting its potential involvement in the disease's pathogenesis. This review summarizes current advancements in elucidating the relationship between ARR3 and myopia, emphasizing genetic variations associated with refractive errors and their implications for myopia research and clinical management. We emphasize the necessity for further studies to elucidate the role of ARR3 in myopia, particularly regarding its impact on visual development and the genetic predisposition observed in specific populations.

The Peripheral Defocus Designed Spectacle Lenses Might Increase Astigmatism in Myopic Children

Purpose

This study aims to explore the impact of wearing peripheral defocus spectacle lenses (PDSL) on cylindrical refractive error (CYL) in myopic children.

Methods

This study included 1057 myopic children and divided the participants into three groups: the HAL group (spectacle lens with highly aspherical lenslets), the MPV group (spectacle lens based on manipulating peripheral vision), and a control group (without myopia control interventions). The study analyzed the effect of wearing PDSL on changes in spherical equivalent refraction, CYL, and corneal astigmatism (CA). The mediating effect between changes in spherical refractive errors (SPH) and CYL was also investigated.

Results

Compared to the control group (0.05 ± 0.33 D), the annual CYL progression was faster in the HAL group (-0.15 ± 0.33 D, P < 0.001) and the MPV group (-0.09 ± 0.27 D, P = 0.019). More children in the HAL group had an annual CYL progression ≥0.50 D (HAL: 23.6%, Control: 16.2%, P = 0.012). The annual CYL and CA progression were consistent within the PDSL groups (HAL: P = 0.677, MPV: P = 0.683). The total effect of CYL progression in the HAL group was primarily due to direct induction from wearing HAL and indirect induction through the SPH control effect.

Conclusions

The application of PDSL could cause increase in astigmatism in myopic children, which could mainly be contributed to cornea astigmatism change.

Translational Relevance

PDSL may passively affect the anterior ocular biomechanics during myopia control, leading to an increase in astigmatism.

Combination Therapy with Atropine 0.05% and Myopi-X® Glasses: Is it Effective in Myopia Control?

Objectives

To investigate whether the combination therapy of Myopi-X® peripheral progressive addition lenses (PAL; Novax®) and atropine 0.05% provides an additive effect compared to monotherapies with either Myopi-X® PAL or atropine 0.05%.

Materials and Methods

This retrospective cross-sectional study reviewed the clinical records of 51 patients, categorized into three groups: 27 in the Myopi-X group, 13 in the atropine 0.05% group, and 11 in the combination therapy group using Myopi-X peripheral PAL with atropine 0.05%. Baseline characteristics, including age, cycloplegic spherical equivalent (SE), and axial length (AL), were compared between the groups. Twelve months after treatment initiation, changes in SE and AL were assessed and compared between the groups.

Results

Among the 51 patients analyzed, the baseline characteristics differed significantly between the groups, with the atropine 0.05% group showing a higher average age, longer AL, and lower SE compared to the other groups. After 12 months, no significant differences were found in SE changes between the treatment groups (p=0.35). Similarly, changes in AL did not significantly differ between the groups (p=0.10), although age had a significant impact on AL change (p=0.01). No significant differences were observed in pairwise comparisons of SE or AL changes between the groups.

Conclusion

In this study, combining atropine 0.05% with Myopi-X PALs did not provide an additive benefit. The literature suggests that both treatments are effective in slowing myopia progression individually; however, in our study, their combination did not significantly improve SE progression or axial elongation compared to monotherapies. Further randomized studies with larger patient groups are needed to confirm these findings and assess long-term effects.

Peripheral refraction and aberrations in myopic eyes after small-incision lenticule extraction (SMILE) surgery

To investigate peripheral refraction and aberrations in myopic eyes after small-incision lenticule extraction (SMILE) surgery and to understand the relationship between visual symptoms and wide-field wavefront aberrations. A total of 28 patients with myopia and myopic astigmatism underwent SMILE surgery. Peripheral refraction and aberrations were measured both before and six months after surgery using a modified wide-field Shack-Hartmann wavefront (SHWS) sensor-based aberrometer. The peripheral refraction and aberrations from the axis (0°) to (15°) in both the horizontal and vertical directions were measured. A visual questionnaire was administered to assess visual quality before and six months after surgery. Post-surgery, peripheral relative refraction exhibited reduced hyperopia. The spherical aberration [Formula: see text] changed from 0.12 ± 0.11 μm before surgery to 0.24 ± 0.14 μm (t = 20.047, P = 0.000) after surgery on the optical axis(0°). Post-surgery, the spatial pattern of spherical aberration remained constant. Greater variability of peripheral aberrations was observed in the direction of the horizontal retina than in the vertical axis after surgery. Horizontal coma significantly increased after surgery and appeared to be more variable in the direction of the surperior region. [Formula: see text] shifted from -0.03 ± 0.16 μm preoperatively to -0.12 ± 0.18 μm postoperatively (t = 0.580, P = 0.573), [Formula: see text] changed from 0.03 ± 0.22μm preoperatively to 0.37 ± 0.35 μm postoperatively (t =  - 3.780, P = 0.003) on the central axis. The majority of patients were satisfied with the postoperative daytime vision; there was no significant deterioration in nighttime visual symptoms compared to preoperative levels. Our study demonstrated that SMILE significantly reduced peripheral refraction in myopic eyes, however with increased asymmetry along the vertical axis. Notably, the relationship between nighttime visual symptoms and large-field aberrations was not found to be significant.

Comparison of Myopic Progression and Quality of Life Wearing Either DIMs Lenses or Single-Vision Myopia Correcting Spectacles

Purpose: To assess the efficacy of the Defocus Incorporated Multiple Segments (DIMS) spectacle lens for myopia control and its impact on vision-related quality of life in Chinese children over a 1-year period. Methods: This randomized double-blind prospective controlled clinical trial enrolled 176 myopic subjects aged between seven and 14 years who were randomly assigned into the DIMS group or the control single-vision (SV) group. Refractive error and axial length measurements at baseline, three-, six-, nine-, and 12-month follow-up visits were monitored. The Quality of Life Impact of Refractive Correction (QIRC) questionnaire was used to evaluate the vision-related quality of life at baseline and at 12 months postintervention. Results: Of the initial cohort, a total of 151 children successfully completed the study (DIMS n = 72; SV n = 79). Baseline characteristics were similar between both groups. Average axial elongation and myopia progression after 1 year were 0.17 (95% CI 0.13-0.20) mm and -0.27 (95% CI -0.36 to -0.18) D in the DIMS group and 0.30 (95% CI 0.26-0.33) mm and -0.55 (95% CI -0.64 to -0.47) D in the SV group. The mean differences in axial elongation and myopia progression were 0.13 mm (95% CI 0.08-0.18 mm, p < 0.001) and -0.28 D (95% CI -0.41 to -0.15 D, p < 0.001) between the two groups. No significant difference in the QIRC score was found between the DIMS and SV groups (55.30 (95% CI 53.17-56.90) versus 54.20 (95% CI 51.99-56.41), p=0.854)). Conclusion: The use of DIMS lenses in children was found to slow down myopia progression compared to SV lenses, without negatively affecting their overall quality of life. Trial Registration: Clinical Trial Registry identifier: ChiCTR2000037443.

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.

Choroidal Control Technology: New Horizons in Maculopathy and Presbyopia

OBJECTIVE

To evaluate changes in choroidal thickness in presbyopes, when reading with regular glasses versus choroidal control glasses, in patients with or without Age-Related Macular Degeneration (AMD).

METHODS

This was a pilot study on short-term axial length (AL) in 33 eyes of 24 presbyopic patients aged 60 to 80 years, assigned to two age-matched groups, with or without AMD. About them, changes in choroidal thickness were evaluated with ocular biometry through indirect measurements of axial length at baseline, after 20' of reading with conventional lenses, and after another 20' of reading with peripheral hyperopic defocus glasses. The differences in axial length between the three different times were analyzed.

RESULTS

In presbyopes without AMD there was a significant axial length shortening of -13.44 microns in the first conventional reading period, which was reversed by 90% with hyperopic defocus lenses, recovering + 12.11 microns by axial lengthening (choroidal thinning, p = 0.03). In patients with AMD, axial shortening was significantly greater than controls, -23.86 microns with conventional lenses (p < 0.001) and they, also increased their axial length with defocus, although this response was smaller in proportion (+ 15.52 microns).

CONCLUSION

Reading with positive lenses produces myopic defocus and choroidal thickening in presbyopes with and without AMD but was significantly greater in the latter. Glasses with Choroidal Control Technology reduced thickening during reading.

KEY MESSAGES

What is known • Presbyopia spectacles for near produce myopic defocus and choroidal thickening. What is new • There are differences in choroidal thickening during reading between normal subjects and those with age related macular degeneration. • Spectacles with Defocus Choroidal Control Technology reduce choroidal thickening during reading in presbyopes.

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.

Myopia in Children: Epidemiology, Genetics, and Emerging Therapies for Treatment and Prevention

Refractive errors, particularly myopia, are among the most prevalent visual impairments globally, with rising incidence in children and adolescents. This review explores the epidemiology and risk factors associated with the development of refractive errors, focusing on the environmental and lifestyle factors contributing to the current surge in myopia. We provide an overview of key genetic factors and molecular pathways driving the pathogenesis of myopia and other refractive errors, emphasizing the complex interplay between genetic predisposition and environmental triggers. Understanding the underlying mechanisms is crucial for identifying new strategies for intervention. We discuss current approaches to slow myopia progression in pediatric populations, including pharmacological treatment regimens (low-dose atropine), optical interventions, and lifestyle modifications. In addition to established therapies, we highlight emerging innovations, including new pharmacological agents and advanced optical devices, and insights into potential future treatments. Cutting-edge research into gene therapy, molecular inhibitors, and neuroprotective strategies may yield novel therapeutic targets that address the root causes of refractive errors. This comprehensive review underscores the importance of early intervention and highlights promising avenues for future research, aiming to provide pediatricians with guidance to ultimately improve clinical outcomes in managing and preventing myopia progression in children and young adults.

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.).

Animal modeling for myopia

Background

Myopia is one of the most common eye diseases globally, and has become an increasingly serious health concern among adolescents. Understanding the factors contributing to the onset of myopia and the strategies to slow its progression is critical to reducing its prevalence.

Main text

Animal models are key to understanding of the etiology of human diseases. Various experimental animal models have been developed to mimic human myopia, including chickens, rhesus monkeys, marmosets, mice, tree shrews, guinea pigs and zebrafish. Studies using these animal models have provided evidences and perspectives on the regulation of eye growth and refractive development. This review summarizes the characteristics of these models, the induction methods, common indicators of myopia in animal models, and recent findings on the pathogenic mechanism of myopia.

Conclusions

Investigations using experimental animal models have provided valuable information and insights into the pathogenic mechanisms of human myopia and its treatment strategies.

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.

Absorption and attachment of atropine to etafilcon A contact lenses

PURPOSE

Myopia (short-sightedness) is a growing vision problem worldwide. Currently atropine eye drops are used to control the progression of myopia but these suffer from potential lack of bioavailability and low ocular residence time. Commercially available myopia control contact lenses are also used to limit myopia progression, but neither atropine nor contact lenses individually completely stop progression. Development of myopia control contact lenses which could deliver therapeutic doses of atropine is thus desirable and may provide increased efficacy. This study was designed to explore the feasibility of attaching atropine to etafilcon A contact lenses through an esterification reaction.

METHODS

Carboxylic acid groups on etafilcon A contact lenses were quantified using Toluidine Blue O. The carboxylic acid groups in etafilcon A contact lenses were activated using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC-HCl) and N-hydroxysuccinimide (NHS) crosslinkers after which atropine was added to undergo potential binding via esterification. Atropine was released from lenses by alkaline hydrolysis. Reverse phase high performance liquid chromatography (HPLC) was used to detect and quantify the released atropine and its degradation products in solution. Contact lenses that had not been activated by EDC-NHS (controls) were also examined to determine the amount of atropine that could be absorbed rather than chemically bound to lenses.

RESULTS

Each etafilcon A contact lens contained 741.1 ± 5.5 µg carboxylic acid groups which may be available for esterification. HPLC had a limit of detection for atropine of 0.38 µg/mL and for tropic acid, an atropine degradation product, of 0.80 µg/mL. The limits of quantification were 1.16 µg/mL for atropine and 2.41 µg/mL for tropic acid in NH4HCO3. The etafilcon A lenses adsorbed up to 7.69 μg atropine when incubated in a 5 mg/mL atropine solution for 24 h. However, there was no evidence that atropine could be chemically linked to the lenses, as washing in a high concentration of NaCl removed all the atropine from the contact lenses with no atropine being subsequently released from the lenses after incubating in 0.01 N NH4HCO3.

CONCLUSIONS

Etafilcon A contact lenses contain free carboxylic acids which may be an appropriate option for attaching drugs such as atropine. Etafilcon A lenses adsorbed up to 7.69 μg atropine, which would be more than enough to deliver atropine to eyes to control myopia. However, atropine could not be chemically bound to the carboxylic acids of the etafilcon A lenses using this methodology.

Comparison of the Effects of Orthokeratology and Highly Aspherical Lenselets in Achieving Myopia Control and Defocus in Adolescents

OBJECTIVES

To compare the control effectiveness and periretinal defocus between orthokeratology (OK) and highly aspherical lenslets (HAL) in adolescents with myopia.

METHODS

In this prospective study, 211 children (211 right eyes) were enrolled in Beijing Ming Vision and Ophthalmology between October 2022 and February 2023. Based on the myopia correction method, participants were divided into three groups: OK, HAL, and single-vision spectacles (SVS). They were further divided into two subgroups according to the spherical equivalent (SE), namely, subgroup A with -1.0≤SE≤-2.0 D and subgroup B with -2.0

RESULTS

Axial length growth in those with OK lenses and HAL was lower than what was observed for those with SVS after 6, 9, and 12 months. Comparison of the difference in AL change between OK and HAL was not statistically significant with -1.0≤SE≤-2.0 D. The myopic defocus of RDV270° to 300° in group HAL was higher than that in group OK, the difference was statistically significant ( P <0.05), and in other regions, the myopic defocus was higher in the group OK. Em, SRI (corneal regularity index), variation in cell area, and corneal thickness were significantly associated with shaping force.

CONCLUSIONS

Orthokeratology is one of the most effective optical treatments for controlling myopia, and the factors that affect the corneal shaping force under different corneal parameters are different. For mild myopia, HAL can achieve the same effectiveness as OK.

Collapse

Key Words Collapse

MESH Headings

• Humans
• Orthokeratologic Procedures/methods
• Adolescent
• Myopia/therapy
• Myopia/physiopathology
• Male
• Prospective Studies
• Female
• Axial Length, Eye/pathology
• Refraction, Ocular/physiology
• Child
• Eyeglasses
• Visual Acuity/physiology
• Contact Lenses
• Follow-Up Studies
• Cornea/pathology
• Cornea/physiopathology

Collapse

Grants Collapse

Affiliation(s)

Jia Yu Ming Vision and Ophthalmology (J.Y., Y.Z.), Jianguomen Branch Clinic, Beijing, China; and Eye School of Chengdu University of TCM (Y.G., Y.Z.), Ineye Hospital of Chengdu University of TCM, Chengdu, Sichuan, China
Yujuan Guo
Yuehua Zhou

Collapse

Three optical intervention methods for low myopia control in children: a one-year follow-up study

OBJECTIVE

This study aimed to compare the one-year efficacy of myopia prevention and control using three optical intervention methods - single vision lens (SVL), high aspherical lenticule (HAL), and orthokeratology (OK) lens - in children with low myopia.

METHODS

A cohort of 150 children aged 7-13 years with low myopia was recruited and divided into three groups: SVL (n = 50), HAL (n = 50), and OK lens group (n = 50), based on their preference for glasses. Follow-up assessments were carried out over one year, focusing on data from the right eye for statistical analysis. Baseline characteristics such as gender, age, axial length (AL), spherical equivalent refractive error (SER), flat keratometry (K1), steep keratometry (K2), anterior chamber depth (ACD), white-to-white corneal diameter (WTW), and non-contact tonometry (NCT) measurements were gathered and compared among the three groups before any intervention. Changes in AL growth after 1 year of intervention were assessed across the three groups. Subsequently, the AL growth control rates between the HAL and OK lens groups were compared, with the SVL group serving as the reference standard.

RESULTS

The study found no statistically significant variances in baseline characteristics (gender, age, SER, AL, K1, K2, WTW, and NCT) among the SVL, HAL, and OK lens groups (all p > 0.05). Following a one-year intervention, AL growth rates were as follows: HAL group (0.163 ± 0.113 mm) < OK lens group (0.280 ± 0.170 mm) < SVL group (0.516 ± 0.190 mm), with statistically significant disparities (p < 0.05). The HAL group demonstrated a higher 1-year AL growth control rate (68.41%) compared to the OK lens group (45.74%) for children aged 7-13 with low myopia, with a statistically significant differences (p < 0.001). And there was significant difference in the SER change between SVL group and HAL group (p < 0.001).

CONCLUSION

Compared to SVL, HAL and OK lens are more effective in controlling axial growth in mild myopia. Specifically, HAL maybe shows superior outcomes in both preventive and corrective measures, also it needs to be supported by more studies from randomized controlled experiments.

Ciliary muscles contraction leads to axial length extension--The possible initiating factor for myopia

PURPOSE

This study aimed to investigate the underlying factors driving the onset of myopia, specifically the role of the ciliary muscle's contraction in the elongation of the axial length of the eye.

METHODS

The retrospective study was conducted utilizing data from three ophthalmic centers in Shanghai and Beijing. Both Chinese and Caucasian children were involved. The axial length of the subjects' eyes was measured in both relaxed and contracted state of the ciliary muscle. A comprehensive mechanical model was also developed to observe the influence of ciliary muscle contraction on the axial length.

RESULTS

This study included a sample of 198 right eyes of 198 myopic children. Of these, 97 were male and 101 were female, 126 were of Chinese ethnicity and 72 were Caucasian. The age of onset for myopia ranged from 5.9 to 16.9 years old. The axial length of the eye decreased 0.028 ± 0.007mm following dilation, indicating relaxation of the ciliary muscle (t paired student = 15.16, p = 6.72 x 10-35). In contrast, ciliary muscle contraction resulted in an increase in axial length. Considering proportionality, a significant 90.4% (179 eyes) exhibited a reduced axial length, while a minor 9.6% (19 eyes) demonstrated an increase post-mydriasis. Finite element modeling demonstrated that muscle contraction caused a tension force that transmits towards the posterior pole of the eye, causing it to extend posteriorly.

CONCLUSION

The contraction of the ciliary muscle leads to an extension of the axial length. This could potentially be the initiating factor for myopia.

Peripheral Refraction Using Ancillary Retinoscope Component (P-ARC)

Purpose

To assess the agreement of retinoscope-based peripheral refraction techniques with the criterion standard open-field autorefractor.

Methods

Fifty young adults (mean age, 24 ± 3 years) participated in this study. Two masked, experienced senior examiners carried out central refraction and peripheral refraction at the temporal 22° (T22°) and nasal 22° (N22°) eccentricities. Peripheral refraction techniques were (a) peripheral refraction using ancillary retinoscope component (P-ARC), (b) retinoscopy with eye rotation, and (c) open-field autorefractor. Peripheral refraction with retinoscopy values was compared with an open-field autorefractor (Shinn Nippon NVision-K) to assess the agreement. All measurements were taken from the right eye under noncycloplegic conditions.

Results

The mean difference ±95% limits of agreement of peripheral refraction values obtained using P-ARC from T22° (+0.11 diopters [D] ± 1.20 D; P = 0.20) or N22° (+0.13 D ± 1.16 D; P = 0.13) were comparable with open-field autorefractor. The eye rotation technique compared to autorefractor showed a significant difference for T22° (+0.30 D ± 1.26 D; P = 0.002); however, there was an agreement for N22° (+0.14 D ± 1.16 D; P = 0.10). With respect to the identification of peripheral refraction patterns, examiners were able to identify relative peripheral hyperopia in most of the participants (77%).

Conclusions

Peripheral refraction with P-ARC was comparable with open-field autorefractor at T22° and N22° eccentricities. Peripheral retinoscopy techniques can be another approache for estimating and identifying peripheral refraction and its patterns in a regular clinical setting.

Translational Relevance

Retinoscope with P-ARC has high potential to guide and enable eye care practitioners to perform peripheral refraction and identify peripheral refraction patterns for effective myopia management.

Treatment of Rapid Progression of Myopia: Topical Atropine 0.05% and MF60 Contact Lenses

This retrospective study evaluates the effectiveness of combining 0.05% atropine with MF60 contact lenses in managing rapid myopia progression in children over one year. The study involved three groups: the treatment group (TG) with 15 children (53% male, average age 12.9 ± 1.04), the MF group (MF) with 12 children (50% male, average age 12.8 ± 0.8) using only MF60 lenses, and the control group (CG) with 14 children (43% male, average age 12.1 ± 0.76). Baseline myopia and axial length (AL) were similar across groups, with the TG, MF, and CG showing -4.02 ± 0.70 D, -4.18 ± 0.89 D, -3.86 ± 0.99 D, and 24.72 ± 0.73 mm, 24.98 ± 0.70 mm, 24.59 ± 1.02 mm, respectively. Prior to the study, all groups exhibited significant myopia and AL progression, with no previous myopia control management. The treatment involved daily 0.05% atropine instillation, the use of MF60 lenses and increased outdoor activity. Biannual cycloplegic refraction and slit lamp evaluations confirmed no adverse reactions. After one year, the TG showed a significant reduction in myopia and AL progression (-0.43 ± 0.46 D, p < 0.01; 0.22 ± 0.23 mm, p < 0.01), whereas the CG showed minimal change (-1.30 ± 0.43 D, p = 0.36; 0.65 ± 0.35 mm, p = 0.533). The MF group also exhibited a notable decrease (-0.74 ± 0.45 D, p < 0.01; 0.36 ± 0.23 mm). Increased outdoor activity during the treatment year did not significantly impact myopia control, suggesting its limited additional effect in this cohort. The study concludes that the combination of 0.05% atropine and peripheral defocus soft contact lenses effectively controls myopia progression in children.

Observation of peripheral refraction in myopic anisometropia in young adults

AIM

To investigate the differences in retinal refraction difference values (RDVs) of adult patients with myopic anisometropia compared with those without myopic anisometropia, and to investigate the relationship between ocular biometric measurements and relative peripheral refraction.

METHODS

This clinical observation study included 130 patients with myopia (-0.25 to -10.00 D) between October 2022 and January 2023 aged between 18 and 40y. The patients were divided into anisometropia (n=63; difference in binocular anisometropia ≥1.00 D) and non-anisometropia (n=67; difference in binocular anisometropia <1.00 D) groups accordingly. Ocular biometric measurements were performed by optical biometrics and corneal topography to assess the steep keratometry (Ks), flap keratometry (Kf), axial length (AL), corneal astigmatism (CYL; Ks-Kf), surface regularity index (SRI), surface asymmetry index (SAI), and central corneal thickness (CCT). The RDV was measured at five retinal areas from the fovea to 53 degrees (RDV-0-10, RDV-10-20, RDV-20-30, RDV-30-40, and RDV-40-53), the total RDV (TRDV) of 53 degrees, and four regions, including RDV-superior, RDV-inferior, RDV-temporal, and RDV-nasal. An analysis of Spearman correlation was carried out to examine the correlation between RDV and the spherical equivalent (SE) and ocular biological parameters.

RESULTS

Within RDV-20-53, both groups showed relative hyperopic defocus, and the increase in RDV corresponds to the increase in eccentricity. In the myopic anisometropia group, the TRDV, RDV-20-53, RDV-superior, and more myopic eyes had significantly higher RDV-temporal values than less myopic eyes. (P<0.05). In the non-anisometropia group, there was no significant difference in the RDV between the more and less myopic eyes at different eccentricities (P>0.05). There was a negative correlation between SE and TRDV (r=-0.205, P=0.001), RDV-20-53 (r=-0.281, -0.183, -0.176, P<0.05), RDV-superior (r=-0.251, P<0.001), and RDV-temporal (r=-0.230, P<0.001), a negative correlation between CYL and RDV-10-30 (r=-0.147, -0.180, P<0.05), and a negative correlation between SRI and RDV-0-20 (r=-0.190, -0.170, P<0.05). AL had a positive correlation with RDV-20-30 (r=0.164, P=0.008) and RDV-temporal (r=0.160, P=0.010).

CONCLUSION

More myopic eyes in patients with myopic anisometropia show more peripheral hyperopic defocus. Diopter and corneal morphology may affect peripheral retinal defocus.

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.

Benchmarking large language models' performances for myopia care: a comparative analysis of ChatGPT-3.5, ChatGPT-4.0, and Google Bard

BACKGROUND

Large language models (LLMs) are garnering wide interest due to their human-like and contextually relevant responses. However, LLMs' accuracy across specific medical domains has yet been thoroughly evaluated. Myopia is a frequent topic which patients and parents commonly seek information online. Our study evaluated the performance of three LLMs namely ChatGPT-3.5, ChatGPT-4.0, and Google Bard, in delivering accurate responses to common myopia-related queries.

METHODS

We curated thirty-one commonly asked myopia care-related questions, which were categorised into six domains-pathogenesis, risk factors, clinical presentation, diagnosis, treatment and prevention, and prognosis. Each question was posed to the LLMs, and their responses were independently graded by three consultant-level paediatric ophthalmologists on a three-point accuracy scale (poor, borderline, good). A majority consensus approach was used to determine the final rating for each response. 'Good' rated responses were further evaluated for comprehensiveness on a five-point scale. Conversely, 'poor' rated responses were further prompted for self-correction and then re-evaluated for accuracy.

FINDINGS

ChatGPT-4.0 demonstrated superior accuracy, with 80.6% of responses rated as 'good', compared to 61.3% in ChatGPT-3.5 and 54.8% in Google Bard (Pearson's chi-squared test, all p ≤ 0.009). All three LLM-Chatbots showed high mean comprehensiveness scores (Google Bard: 4.35; ChatGPT-4.0: 4.23; ChatGPT-3.5: 4.11, out of a maximum score of 5). All LLM-Chatbots also demonstrated substantial self-correction capabilities: 66.7% (2 in 3) of ChatGPT-4.0's, 40% (2 in 5) of ChatGPT-3.5's, and 60% (3 in 5) of Google Bard's responses improved after self-correction. The LLM-Chatbots performed consistently across domains, except for 'treatment and prevention'. However, ChatGPT-4.0 still performed superiorly in this domain, receiving 70% 'good' ratings, compared to 40% in ChatGPT-3.5 and 45% in Google Bard (Pearson's chi-squared test, all p ≤ 0.001).

INTERPRETATION

Our findings underscore the potential of LLMs, particularly ChatGPT-4.0, for delivering accurate and comprehensive responses to myopia-related queries. Continuous strategies and evaluations to improve LLMs' accuracy remain crucial.

FUNDING

Dr Yih-Chung Tham was supported by the National Medical Research Council of Singapore (NMRC/MOH/HCSAINV21nov-0001).