Effects of local myopic defocus on refractive development in monkeys

Association between myopia and relative peripheral refraction in children with monocular Tilted disc syndrome

BACKGROUND

This study aimed to investigate the refractive error and relative peripheral refraction in pediatric patients with monocular tilted disc syndrome.

METHODS

This single-center, prospective, cross-sectional, observational study included 49 patients from the Pediatric Ophthalmology Department of the Second Hospital of Hebei Medical University aged 5-17 years with monocular tilted disc syndrome. Eyes with tilted optic discs formed the study group, and contralateral eyes with normal discs served as controls, with mean spherical equivalents of - 3.24 D and - 0.47 D, respectively. Best-corrected visual acuity, spherical equivalent, axial length, tilt ratio, defined as the ratio of maximum to minimum disc diameters, and relative peripheral refraction, assessing myopia-related defocus were compared between groups. Pearson's correlation analysis assessed associations between optic disc tilt and spherical equivalent, axial length, and the total refraction difference value.

RESULTS

Tilted optic discs were associated with significantly greater myopia (- 3.24 ± 1.83 D in tilted eyes and - 0.47 ± 0.72 D in non-tilted eyes, P <.001), longer axial length (24.59 ± 1.04 mm in tilted eyes and 23.45 ± 0.78 mm in non-tilted eyes, P <.001), and a higher tilt ratio (1.43 ± 0.05 in tilted eyes and 1.14 ± 0.04 in non-tilted eyes, P <.001). Discrepancies between tilted and non-tilted eyes were observed in the superior, inferior, and nasal quadrants, and the total refraction difference value (P <.001). In eyes with tilted disc syndrome, a negative correlation was found between the total refraction difference value and the spherical equivalent (P <.001). The tilt ratio of optic disc eyes was significantly greater than that of contralateral eyes and was negatively correlated with the spherical equivalent. There was a positive correlation between the tilt ratio and axial length (P <.001).

CONCLUSIONS

Pediatric patients with monocular tilted disc syndrome exhibited longer axial lengths, more myopic spherical equivalent, and more positive relative peripheral refraction. A greater tilt ratio is associated with larger relative peripheral refraction and axial length, corresponding to more severe myopia.

Myopia control efficacy of peripheral defocus modifying spectacle lenses in children and adolescents: a Meta-analysis

AIM

To evaluate the effects of microlens design of peripheral defocus modifying spectacle lenses (PDMSLs) and non-microlens design of PDMSLs on controlling myopia progression in children and adolescents.

METHODS

A systematic search was carried out in the PubMed, Cochrane Library, Embase, CNKI, and Web of Science databases. The search targeted randomized controlled trials (RCTs) and cohort studies (CTs) that explored the effects of PDMSLs on myopia control among children and adolescents. The Cochrane risk-of-bias tool and the Newcastle-Ottawa Scale were employed to evaluate the risk of bias in the included studies. The published biases of the included studies were evaluated using Egger's test.

RESULTS

Nine studies (7 RCTs, 2 CTs) were included, involving 4332 participants in the PDMSLs group and 7317 participants in the single vision lenses (SVLs) group. Meta-analysis showed that PDMSLs with microlens design had lower change in spherical equivalent refraction (SER) than SVLs at 6, 12, 18, and 24mo after wearing glasses, with reductions of 0.19 D (95%CI: 0.14 to 0.24, P<0.00001), 0.36 D (95%CI: 0.25 to 0.46, P<0.00001), 0.43 D (95%CI: 0.32 to 0.55, P<0.00001), and 0.51 D (95%CI: 0.33 to 0.69, P<0.00001), respectively. The changes in axial length (AL) were also lower in PDMSLs compared to SVLs, with reductions of -0.09 mm (95%CI: -0.13 to -0.04, P=0.0002), -0.15 mm (95%CI: -0.21 to -0.08, P<0.00001), -0.27 mm (95%CI: -0.34 to -0.20, P<0.00001), and -0.29 mm (95%CI: -0.38 to -0.20, P<0.00001), respectively. There was no significant difference between the non-microlens group and SVLs in controlling the changes of SER and AL in myopia (both P>0.05).

CONCLUSION

The synthesized evidence indicates superior myopia management outcomes with microlens design of PDMSLs compared to both SVLs and non-microlens design of PDMSLs in children and adolescents.

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.

Experimental and modeling analysis of lenses with concentric cylindrical annular refractive elements: impact on peripheral imaging

The mechanism by which myopia-managing spectacle lenses slow myopia progression remains controversial. Understanding the changes these lenses introduce to peripheral imaging properties helps shed light on this controversial issue. Given the difficulty of directly measuring these changes in clinical settings, this study combined experimental and modeling approaches to evaluate changes in images at the retina induced by myopia-managing lenses. Optical characteristics that may related to the efficacy of the lenses with concentric cylindrical annular refractive elements (CARE) in myopia control were investigated. Three lenses were evaluated: MyoCare (MC), MyoCare S (MCS), and a single vision (SV) lens with a custom-built physical eye model and optical simulations for the analysis. The simulated PSFs are consistent with the measured ones. PSF analysis showed that MC and MCS lenses produce discrete curves, resulting in remarkable distortion in the simulated retina images, especially for large eccentricities. Whether they increase or decrease contrast depends on the spatial frequencies and eccentricities. These lenses also increase retinal light intensity at different eccentricities. The positive power of the CARE structure introduces myopic defocus of less than 0.25 D at only a limited range of eccentricities. The proposed approaches present relatively straightforward techniques for evaluating the optical performance of myopia-managing spectacle lenses.

Effect of spectacle lenses with highly aspherical lenslets on changes in peripheral eye length and asymmetry

PURPOSE

Spectacle lenses with highly aspherical lenslets (HAL) have been shown to slow myopia progression and axial length (AL) elongation effectively. The effects of HAL on peripheral eye length (PEL) and peripheral refraction (PR) were investigated in children who continued wearing HAL or switched from single-vision spectacle lenses (SVL) or spectacle lenses with slightly aspherical lenslets (SAL) to HAL.

METHODS

Fifty-two participants who had worn HAL for 2 years continued their use (HAL group), while 51 and 48 participants who had originally worn SAL or SVL for 2 years switched to HAL (SAL-HAL and SVL-HAL groups, respectively) in Year 3. A new SVL group of 56 participants, 10-15 years of age, was enrolled in Year 3 (new-SVL group). PEL and PR were measured every 10° from 30° nasal to 30° temporal and from 30° superior to 10° inferior retina.

RESULTS

There were significant differences in the changes in AL and PEL on the temporal side among the groups (all p ≤ 0.001). All three HAL groups exhibited less elongation than the new-SVL group. PR changes in the parafoveal temporal (p = 0.002) and superior (p = 0.001) regions differed among the groups; the new-SVL group progressed more than the other three groups. The AL in the new-SVL group exhibited greater elongation than the PEL (all p < 0.02). However, there were no significant differences between the AL and PEL changes in the three HAL groups (all p > 0.05).

CONCLUSIONS

Compared with wearing SVL, switching to or continuing to wear HAL could slow central and temporal elongation of eye length. Wearing HAL could impact retinal steepness and symmetry.

Interaction of retinal electrophysiology and novel orthokeratology lens use on myopia control efficacy in children

AIMS

The relationship between retinal electrophysiological function and myopia progression was evaluated in school-aged children wearing Breath-O-Correct Orthokeratology (OK) lenses compared with those wearing single vision (SV) lenses over 24 months.

METHODS

In this randomised, single-blind, parallel controlled trial, children aged 8-12 years with -1.00 to -4.00 D of myopia were recruited. Retinal function was evaluated using global-flash multifocal electroretinography at baseline before OK or SV treatment. Axial length was evaluated at 6-month intervals up to 24 months. The main outcome measures were axial elongation (AE) between groups and the interactive effect of baseline retinal function.

RESULTS

A total of 70 children (43 OK, 9.8±1.3 years; 27 SV, 9.5±1.4 years) completed the 2-year study and were included in the analysis. The 2-year normalised AE was 0.37±0.37 mm in the OK group and 0.60±0.41 mm in the SV group, respectively. For children in the SV group, the amplitude of the central inner retinal response was negatively correlated with axial length elongation (p=0.03). In contrast, this relationship between retinal electrophysiology and AE was not observed in OK group, indicating that they were independent of each other in children treated with OK (p=0.33).

CONCLUSION

A weak retinal electrophysiological response was a risk factor for rapid AE in SV controls. However, OK treatment can lower this risk factor and significantly reduce AE in school-aged children.

Repeatability and agreement of multispectral refraction topography in school children before and after cycloplegia

BACKGROUND

The purpose of this study was to evaluate the repeatability and agreement of multispectral refraction topography (MRT) in measuring retinal refraction before and after cycloplegia in children. The results of this study will provide valuable insights into the accuracy and reliability of MRT as a tool for assessing retinal refraction in pediatric patients.

METHODS

Children aged 7 to 18 years old were recruited for this prospective research. The central and peripheral retinal refraction was measured three times using multispectral refraction topography (MRT) before and after cycloplegia. The retinal deviation value (RDV) was used to describe the average peripheral refractive error of the retina. In addition, objective refraction (OR) and subjective refraction (SR) measurements were also performed.

RESULTS

A total of 60 children with a mean age of 10.50 ± 1.81 years were enrolled. Before cycloplegia, all the central and peripheral retinal refraction parameters showed good repeatability with the lowest intraclass correlation coefficient (ICC) being 0.78 in the retinal deviation value from 45° eccentricity to 53° of the retina (RDV 45-53). After cycloplegia, the repeatability of MRT was significantly enhanced (lowest ICC = 0.91 in RDV-I). The 95% limits of agreement (LoA) of the central refraction and OR ranged from - 2.1 to 1.8 D before cycloplegia, and from - 1.69 to 0.27 D after cycloplegia. The 95% LoA of the central refraction and SR ranged from - 1.57 to 0.36 D after cycloplegia. All the 95% LoA demonstrated high agreement.

CONCLUSIONS

The MRT shows high agreement with autorefractometry and experienced optometrist in measuring central refraction. Additionally, the MRT provides good repeatable measurements of retinal peripheral refraction before and after cycloplegia in schoolchildren.

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.

Retinoscopes: Past and present

BACKGROUND

Retinoscopy is arguably the most important method in the eye clinic for diagnosing and managing refractive errors. Advantages of retinoscopy include its non-invasive nature, ability to assess patients of all ages, and usefulness in patients with limited cooperation or communication skills.

AIM

To discuss the history of retinoscopes and examine current literature on the subject.

METHODS

A search was conducted on the PubMed and with the reference citation analysis (https://www.referencecitationanalysis.com) database using the term "Retinoscopy," with a range restricted to the last 10 years (2013-2023). The search string algorithm was: "Retinoscopy" (MeSH Terms) OR "Retinoscopy" (All Fields) OR "Retinoscopes" (All Fields) AND [(All Fields) AND 2013: 2023 (pdat)].

RESULTS

This systematic review included a total of 286 records. Publications reviewed iterations of the retinoscope into autorefractors, infrared photo retinoscope, television retinoscopy, and the Wifi enabled digital retinoscope.

CONCLUSION

The retinoscope has evolved significantly since its discovery, with a significant improvement in its diagnostic capabilities. While it has advantages such as non-invasiveness and broad applicability, limitations exist, and the need for skilled interpretation remains. With ongoing research, including the integration of artificial intelligence, retinoscopy is expected to continue advancing and playing a vital role in eye care.

Parallel comparison of ocular metrics in non-human primates with high myopia by LS900, ultrasonography and MRI-based 3D reconstruction

We investigate the ocular dimensions and shape by using Lenstar900 (LS900), A-scan ultrasonography, and Magnetic Resonance Imaging (MRI) in highly myopic Macaca fascicularis. The ocular dimensions data of LS900, A-scan ultrasonography and MRI was assessed from 8 eyes (4 adult male cynomolgus macaque) with extremely high myopia (≤-1000DS) and compared by means of coefficients of concordance and 95% limits of agreement. Multiple regression analysis was performed to explore the associations between ocular biometry, volume, refraction and inter-instrument discrepancies. Test-retest reliability of three measurements of ocular parameters at two time points was almost equal (intraclass correlation = 0.831 to 1.000). The parallel-forms reliability of three measurements was strong for vitreous chamber depth (VCD) (coefficient of concordance = 0.919 to 0.981), moderate for axial length (AL) (coefficient of concordance = 0.486 to 0.981), and weak for anterior chamber depth (ACD) (coefficient of concordance = 0.267 to 0.621) and lens thickness (LT) (coefficient of concordance = 0.035 to 0.631). The LS900 and MRI systematically underestimated the ACD and LT comparing to A-scan ultrasonography (P < 0.05). Notably, the average AL on LS900 displayed a significant correlation with those on MRI (r = 0.978, P < 0.001) and A-scan ultrasonography (r = 0.990, P < 0.001). Almost 4/5 eyeballs were prolate. The mean eyeball volume positively correlated with AL (r = 0.782, P = 0.022), the width (r = 0.945, P = 0.000), and the length (r = 0.782, P = 0.022) of eyeball, while negatively correlated with SER (r = -0.901, P = 0.000). In conclusion, there was a high inter-instrument concordance for VCD with LS900, A-scan ultrasonography and MRI, while ACD and LT were underestimated with LS900 compared to A-scan ultrasonography, and the LS900 and A-scan ultrasonography could reliably measure the AL. MRI further revealed an equatorial globe shape in extremely myopic non-human primates.

The induced defocus by Defocus Incorporated Soft Contact lenses is dependent on visual distance and ambient illuminance

PURPOSE

Defocus Incorporated Soft Contact (DISC) lenses, a commonly used type of multifocal lens in clinical practice, may slow down myopia progression by inducing myopic retinal defocus. The purpose of this study was to explore whether the induced defocus across the retina could be affected by visual environments encountered in the real world, such as differences in viewing distance and ambient illuminance.

METHODS

In this cross-over trial, 30 myopic adults wore both DISC lenses and single vision contact (SVC) lenses in random order. An open-view Hartmann-Shack scanning wavefront sensor was used to measure defocus at different retinal locations along the horizontal meridian under four experimental conditions: far target (3 m) and near targets (0.33 m) under scotopic (<1 lux) or photopic (~300 lux) conditions.

RESULTS

The results showed that DISC lenses induced more myopic retinal defocus than SVC lenses in all conditions (all p < 0.05), except for the scotopic near target. In addition, for DISC lenses, the defocus was greater in the photopic than the scotopic conditions for both the far and near targets (both p < 0.05).

CONCLUSION

In conclusion, the retinal defocus induced by these multifocal lenses was dependent on both visual distance and ambient illuminance, indicating that the visual conditions might affect the anti-myopia efficacy of these devices.

Myopia control efficacy of peripheral defocus soft contact lenses in children and adolescents: A meta-analysis

OBJECTIVES

To evaluate the effect of peripheral defocus soft contact lenses (PDSCLs) on controlling myopia progression in children and adolescents, and to compare it with orthokeratology (Ortho-K) and single vision lenses (SVLs).

METHODS

We conducted a systematic search of PubMed, the Cochrane Library, Medline, CNKI, CBM, VIP, and WanFang Data databases for randomized controlled trials (RCTs) and cohort studies that investigated the effects of PDSCLs on myopia control in children and adolescents. The published languages were limited to English and Chinese. The risk bias tool provided by the Cochrane risk-of-bias tool and Newcastle-Ottawa Scale were used to assess the risk bias of included studies of RCTs and CTs. The published biases of included studies were assessed by Egger`s test.

RESULTS

We included 21 studies, comprising 13 RCTs and 8 cohort studies, with a total of 1337 participants in the PDSCLs group, 428 in the Ortho-K group, and 707 in the SVLs group. The meta-analysis indicated no significant difference between PDSCLs and Ortho-K in controlling the increase of diopter (MD = 0.01, 95% CI: -0.06, 0.09; P = 0.69) and axial length (MD = -0.01, 95% CI: -0.02, 0.00; P = 0.28). Compared with SVLs, PDSCLs had a better effect in controlling the increase of diopter (MD = 0.23, 95% CI: 0.17, 0.28; P < 0.00001) and axial length (MD = -0.11, 95% CI: -0.12, -0.09; P < 0.00001) in children and adolescents.

CONCLUSIONS

Children and adolescents wearing PDSCLs can achieve better myopia control than those wearing SVLs, and their effect is comparable to that of Ortho-K.

Mechanisms of emmetropization and what might go wrong in myopia

Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system that uses retinal image defocus as an error signal, a mechanism called emmetropization. The sensor to detect defocus and its sign resides in the retina itself. The retina and/or the retinal pigment epithelium (RPE) presumably releases biochemical messengers to change choroidal thickness and modulate the growth rates of the underlying sclera. A central question arises: if emmetropization operates as a closed-loop system, why does it not stop myopia development? Recent experiments in young human subjects have shown that (1) the emmetropic retina can perfectly distinguish between real positive defocus and simulated defocus, and trigger transient axial eye shortening or elongation, respectively. (2) Strikingly, the myopic retina has reduced ability to inhibit eye growth when positive defocus is imposed. (3) The bi-directional response of the emmetropic retina is elicited with low spatial frequency information below 8 cyc/deg, which makes it unlikely that optical higher-order aberrations play a role. (4) The retinal mechanism for the detection of the sign of defocus involves a comparison of defocus blur in the blue (S-cone) and red end of the spectrum (L + M-cones) but, again, the myopic retina is not responsive, at least not in short-term experiments. This suggests that it cannot fully trigger the inhibitory arm of the emmetropization feedback loop. As a result, with an open feedback loop, myopia development becomes "open-loop".

Assessment of OCT-Based Macular Curvature and Its Relationship with Macular Microvasculature in Children with Anisomyopia

INTRODUCTION

To evaluate the intraocular differences in optical coherence tomography (OCT)-based macular curvature index (MCI) among children with anisomyopia and to investigate the relationship between MCI and the macular microvasculature.

METHODS

Fifty-two schoolchildren with anisometropia > 2.00 D were enrolled and underwent comprehensive examinations including cycloplegic refraction, axial length (AL), and swept source OCT/OCT angiography. OCT-based MCIs were determined from horizontal and vertical B-scans by a customized curve fitting model in MATLAB R2022 at 1-mm-, 3-mm-, and 6-mm-diameter circles at fovea. Characteristics and topographic variation of MCI was analyzed, and the relationships with microvascularity and its associated factors were investigated.

RESULTS

MCI achieved high reliability and repeatability. There were overall larger MCIs in the more myopic eyes than the less myopic eyes in 1-mm-, 3-mm-, and 6-mm-diameter circles at fovea (all p < 0.001). For the topographic variation, horizontal MCI was significantly greater than vertical MCI (all p < 0.001), and was the largest in 6-mm circle, followed by 3-mm and 1-mm circles. Stronger correlation of horizontal MCI with myopic severity than vertical MCI was found. Partial Pearson's correlation found MCI was negatively associated with deep capillary plexus (DCP) vessel density (p = 0.016). Eyes with a higher MCI in a 6-mm circle were more likely to have longer AL (p < 0.001), lower DCP vessel density (p = 0.037), and thinner choroidal thickness (ChT) (p = 0.045).

CONCLUSION

Larger MCI was found in the more myopic eyes of children with anisomyopia and was significantly associated with smaller DCP density, suggesting that MCI was an important indicator of myopia-related retinal microvascularity change, and it could be a valuable metric for myopia assessment in children.

Benefits and risks of orthokeratology treatment: a systematic review and meta-analysis

BACKGROUND

This meta-analysis reviews the evidence for the risks and benefits associated with orthokeratology (OK) treatment compared with other methods of myopia control in children and adults.

METHODS

A systematic search of Cochrane Central Register of Controlled Trials, Pubmed, Embase and Ovid was conducted from database inception to 22nd August 2021. Studies that reported on risks, visual and ocular biometric effects of OK in patients > 5 years of age with myopia (- 0.75 to - 6.00D) were included. Main outcomes are change in axial length and any adverse event.

RESULTS

Fourty-five papers were included in this systematic review and meta-analysis. The quality of data was variable and of moderate certainty, and selection bias likely skewed the results towards a relative benefit for OK. The rate of axial elongation in children was lower for OK treatment compared to other treatment modalities at one year (MD - 0.16 mm, 95% CI - 0.25 to - 0.07). Rate of change in axial length in children rebounded after OK discontinuation compared to participants who continued treatment (MD 0.10 mm, 95% CI 0.06 to 0.14). Adults and children wearing OK were up to 3.79 times more likely to experience an adverse event when compared with conventional contact lenses (OR 3.79, 95% CI 1.24 to ll.), though this evidence base is underdeveloped and requires additional well-designed studies for substantial conclusions to be drawn.

CONCLUSIONS

OK arrests myopia progression while in use, however, there remain unanswered questions about the optimal duration of treatment, discontinuation effects and long-term risk for adverse events.

Myopia Control: Are We Ready for an Evidence Based Approach?

INTRODUCTION

Myopia and its vision-threatening complications present a significant public health problem. This review aims to provide an updated overview of the multitude of known and emerging interventions to control myopia, including their potential effect, safety, and costs.

METHODS

A systematic literature search of three databases was conducted. Interventions were grouped into four categories: environmental/behavioral (outdoor time, near work), pharmacological (e.g., atropine), optical interventions (spectacles and contact lenses), and novel approaches such as red-light (RLRL) therapies. Review articles and original articles on randomized controlled trials (RCT) were selected.

RESULTS

From the initial 3224 retrieved records, 18 reviews and 41 original articles reporting results from RCTs were included. While there is more evidence supporting the efficacy of low-dose atropine and certain myopia-controlling contact lenses in slowing myopia progression, the evidence about the efficacy of the newer interventions, such as spectacle lenses (e.g., defocus incorporated multiple segments and highly aspheric lenslets) is more limited. Behavioral interventions, i.e., increased outdoor time, seem effective for preventing the onset of myopia if implemented successfully in schools and homes. While environmental interventions and spectacles are regarded as generally safe, pharmacological interventions, contact lenses, and RLRL may be associated with adverse effects. All interventions, except for behavioral change, are tied to moderate to high expenditures.

CONCLUSION

Our review suggests that myopia control interventions are recommended and prescribed on the basis of accessibility and clinical practice patterns, which vary widely around the world. Clinical trials indicate short- to medium-term efficacy in reducing myopia progression for various interventions, but none have demonstrated long-term effectiveness in preventing high myopia and potential complications in adulthood. There is an unmet need for a unified consensus for strategies that balance risk and effectiveness for these methods for personalized myopia management.

Visual performance of optical films utilizing Spatio-Temporal Optical Phase technology

SIGNIFICANCE

Spatio-Temporal Optical Phase technology utilizes film pairs containing optical elements applied to standard single-vision spectacle lenses. This technology provides a dynamic optical cue that may have efficacy in reducing the rate of myopia progression, but the visual performance of this technology is unknown.

PURPOSE

This study aimed to assess the visual performance of film pairs containing optical elements (tests) and a film pair with no optical elements (control).

METHODS

In this randomized, single-masked, bilateral wear study, 42 participants aged 18 to 40 years wore four test designs (E, F-1, G, and F-2) and the control. Subjective data (subjective ratings [1 to 10 scale]: clarity of vision [far-away, intermediate, near] and vision [at night, while walking, overall satisfaction], and willingness to purchase [yes/no response]) were collected after 3 days. Visual acuity (VA)-based measures (monocular high/low-contrast VA [6 m], contrast sensitivity [6 m], and binocular high-contrast VA [6 m and 40 cm]) were collected at dispensing. Visual acuity-based measures were also collected while wearing spectacles with no film. Analyses were performed using linear mixed models and the χ2 test. Significance was set at 5%.

RESULTS

The control performed better than any test for all subjective ratings (mean differences, 1.6 to 3.1 units: p<0.001), willingness to purchase (p<0.001), and designs F-1 and F-2 for binocular high-contrast VA at 40 cm (p=0.001 and p=0.01, respectively). Clarity of vision was significantly worse with F-2 compared with F-1 and G (p<0.001 and p=0.02, respectively). There were no differences between tests for any other subjective rating (p>0.1), willingness to purchase (p=0.11), or any VA-based measure (p>0.08). There were no differences between control and spectacles with no film for any VA-based measure (p>0.08).

CONCLUSIONS

All four test film pairs reduced visual performance compared with control to a degree comparable with other myopia management devices. There was no difference in visual performance between three of the four test film pairs.

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.

Evaluating the Effect of a Myopia Control Spectacle Lens Among Children in Israel: 12-Month Results

PURPOSE

To investigate the effectiveness of a novel spectacle lens designed to slow the progression of myopia in children.

DESIGN

A prospective, randomized, double blind clinical trial.

METHODS

One hundred twenty-six Israeli children aged 6-13 years with spherical equivalent (SER) refractive errors of -0.5 to -6.25 diopters (D) were randomized into either the Shamir Myopia Control (SMC) lens design group or the conventional single-vision spectacle lenses (SVL), the control group. Outcomes measured were changes in axial length and cycloplegic refraction as well as subjective rating of visual experience over a period of 12 months.

RESULTS

At 12 months, AL and SER progression were slowed by 0.11 mm (35%, P < .05) and 0.16 D (25%, P = .122), respectively. In the subgroup of 6-10-year-olds, AL and SER progression were slowed by 0.17 mm (41%, P < .05) and 0.31 D (43%, P < .05), respectively. Similarly, for the subgroup of children with 2 myopic parents AL and SER progression were slowed by 0.15 mm (45% P < .05) and 0.36 D (42%, P < .05), respectively. Subjective visual experience reported in the 12-month questionnaire revealed no difference between the SMC and SVL groups, and average daily wearing hours were also not different between the groups: 14 (±1.4) and 13.8 (±2.3) hours, respectively. The study continues to its second year.

CONCLUSIONS

SMC lenses were effective in slowing the progression of SER and AL, especially for younger children and those having 2 myopic parents. The subjective rating of visual experience and the daily duration of use reported by the SMC group at 12 months were similar to the control group, indicating good lens tolerability.

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

PURPOSE

To compare the effect of orthokeratology (ortho-k) using aspheric or spherical base curve (BCA vs. BCS) contact lenses on axial elongation and the relative peripheral refraction change (RPRC) in Chinese children.

METHODS

Children aged 8-12 years with myopia between -0.75 and -4.00 D and astigmatism ≤1.00 D were randomly assigned to the BCA or BCS group. Peripheral refraction was assessed at 10°, 20° and 30° along the temporal and nasal retina at baseline and at the 12-month visit. Axial length (AL) was measured under cycloplegia at baseline and at the 6- and 12-month visits. Only right eye data were analysed. Repeated-measures analysis of covariance was performed to examine the differences in axial elongation and the RPRC between the BCA and BCS groups.

RESULTS

The 1-year results from 31 BCA and 32 BCS subjects were analysed. No significant between-group differences were found at baseline (p ≥ 0.28). At the 12-month visit, the BCA lens produced a greater absolute RPRC along the horizontal meridian than the BCS lens (p < 0.001). Axial elongation was slower in the BCA group (0.19 ± 0.20 mm) than in the BCS group (0.29 ± 0.14 mm; p = 0.03). Axial elongation was correlated with the RPRC at 10° (r = 0.43, p = 0.02) and 20° (r = 0.39, p = 0.03) along the temporal retina in the BCA group; however, these correlations were not observed in the BCS group.

CONCLUSION

The BCA ortho-k lens could improve the efficacy of slowing axial elongation in children. The improved myopia control observed in the BCA group may be the result of a larger myopic shift in relative peripheral refraction within 20° along the temporal retina.

Clinical Evaluation of MyoCare in Europe (CEME): study protocol for a prospective, multicenter, randomized, double-blinded, and controlled clinical trial

BACKGROUND

Myopia prevalence has been increasing in the last decades, and its pathological consequences, including myopic maculopathy and high myopia-associated optic neuropathy, are now one of the most common causes of visual impairment. It is estimated that by 2050, more than 50% of Europeans and Americans will be myopes, which is alarming due to the high morbidity of myopes over - 6.00D. Once myopia has appeared, there are different options with scientific evidence to try to slow the axial length growth. Ophthalmic lenses are the less invasive treatment to control myopia, and there is evidence about the efficacy of different designs, mainly in the Asiatic population. However, new designs have been launched, and it is not known if efficacy is the same between Asiatic and European subjects. Thus, we have set up a randomized, controlled, double-blind, and multicenter trial to investigate the efficacy of a new design of ophthalmic lenses for myopia control in European children.

METHODS

A 2-year prospective, multicenter, randomized controlled, and double-blind clinical trial is used to investigate the efficacy of a new design of ophthalmic lenses to slow the progression of myopia. Three hundred children aged from 6 to 13 years old will be recruited and randomly assigned to a study or control group. The study group will be composed of 150 children wearing MyoCare while the control group will be composed of 150 children wearing Clearview. The inclusion criteria will be myopia with a spherical equivalent between - 0.75D and - 5.00D, astigmatism < 1.50D, and anisometropia < 1.00D and having a historical evolution of at least - 0.50 The primary outcome is to compare the mean annual progression of the spherical equivalent between both groups. The secondary outcomes are axial length, choroidal thickness, phorias, and accommodative status of both groups.

DISCUSSION

This study will be the first randomized and controlled clinical trial in European children with spectacle lenses based on simultaneous competing defocus. The results will shed light on the clinical evidence of spectacle lenses relying on this new design for the management of myopia with results of efficacy in the non-Asiatic population.

TRIAL REGISTRATION

EU Clinical Trials Register (EudraCT) 2022-001696. Registered on 27 April 2022.

CLINICALTRIALS

gov NCT05919654. Registered on 26 June 2023.

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.

Retinal ganglion cells encode differently in the myopic mouse retina?

The etiology of myopia remains unclear. This study investigated whether retinal ganglion cells (RGCs) in the myopic retina encode visual information differently from the normal retina and to determine the role of Connexin (Cx) 36 in this process. Generalized linear models (GLMs), which can capture stimulus-dependent changes in real neurons with spike timing precision and reliability, were used to predict RGCs responses to focused and defocused images in the retinas of wild-type (normal) and Lens-Induced Myopia (LIM) mice. As the predominant subunit of gap junctions in the mouse retina and a plausible modulator in myopia development, Cx36 knockout (KO) mice were used as a control for an intact retinal circuit. The kinetics of excitatory postsynaptic currents (EPSCs) of a single αRGC could reflect projection of both focused and defocused images in the retinas of normal and LIM, but not in the Cx36 knockout mice. Poisson GLMs revealed that RGC encoding of visual stimuli in the LIM retina was similar to that of the normal retina. In the LIM retinas, the linear-Gaussian GLM model with offset was a better fit for predicting the spike count under a focused image than the defocused image. Akaike information criterion (AIC) indicated that nonparametric GLM (np-GLM) model predicted focused/defocused images better in both LIM and normal retinas. However, the spike counts in 33% of αRGCs in LIM retinas were better fitted by exponential GLM (exp-GLM) under defocus, compared to only 13% αRGCs in normal retinas. The differences in encoding performance between LIM and normal retinas indicated the possible amendment and plasticity of the retinal circuit in myopic retinas. The absence of a similar response between Cx36 KO mice and normal/LIM mice might suggest that Cx36, which is associated with myopia development, plays a role in encoding focused and defocused images.

Size of living space as a moderator for central and peripheral refractions in children

Undesirable living environment may impose risk on myopia development. Furthermore, peripheral refractive error was suggested to contribute to juvenile eye growth modulation. This study aimed to investigate the interaction between peripheral refractive error and living environment in relation to central refractive status in Hong Kong schoolchildren. Central and peripheral refractive errors, axial length (AL), and corneal radius of curvature (CR) were measured in 573 schoolchildren (age 9.5 ± 0.9 years). The AL/CR ratio was used to represent the central refractive status, accounting for non-cycloplegic refraction. The relative peripheral refractive errors (RPRE) up to ± 20° eccentricities were converted into power vectors: spherical-equivalent error (SER) and J₀ astigmatic components and fitted with quadratic equations. The second-order coefficients of SER (a_SER) and J₀ astigmatism (a_J0) and home size reported by parental questionnaires were analyzed to indicate their relationships with AL/CR. Our results showed that children with higher AL/CR lived in smaller homes (p = 0.01) and had a more hyperopic (p < 0.001) but less astigmatic RPRE (p = 0.01). We further analyzed the relationship between AL/CR with RPRE for children living in small (< 300 ft²), moderate (300-600 ft²), and large home sizes (> 600 ft²). Regardless of the home size, a higher AL/CR remained moderately correlated with a more hyperopic a_SER (all p < 0.001). However, a higher AL/CR was associated with a more positive a_J0 only in children living in large homes, and the relationships were not significant for small and moderate home sizes. Linear regression models further indicated that home size was a significant moderator contributing to the relationship between AL/CR and a_J0. In conclusion, our results were consistent with previous studies, showing that children with axial myopia usually lived in smaller homes and had more hyperopic defocus and more positive J₀ astigmatism. However, the relationship between peripheral astigmatism and axial refraction was modulated by the home size of Hong Kong schoolchildren. While peripheral astigmatism is hypothesized as a visual cue for axial refractive development in children, extrinsic environmental factors, such as home size, might interfere with the relationship and dominate refractive development.

Myopia progression risk assessment score (MPRAS): a promising new tool for risk stratification

Timely identification of individuals "at-risk" for myopia progression is the leading requisite for myopia practice as it aids in the decision of appropriate management. This study aimed to develop 'myopia progression risk assessment score' (MPRAS) based on multiple risk factors (10) to determine whether a myope is "at-risk" or "low-risk" for myopia progression. Two risk-score models (model-1: non-weightage, model-2: weightage) were developed. Ability of MPRAS to diagnose individual "at-risk" for myopia progression was compared against decision of five clinicians in 149 myopes, aged 6-29 years. Using model-1 (no-weightage), further 7 sub-models were created with varying number of risk factors in decreasing step-wise manner (1a: 10 factors to 1g: 4 factors). In random eye analysis for model-1, the highest Youden's J-index (0.63-0.65) led to the MPRAS cut-off score of 41.50-43.50 for 5 clinicians with a sensitivity ranging from 78 to 85% and specificity ranging from 79 to 87%. For this cut-off score, the mean area under the curve (AUC) between clinicians and the MPRAS model ranged from 0.89 to 0.90. Model-2 (weighted for few risk-factors) provided similar sensitivity, specificity, and AUC. Sub-model analysis revealed greater AUC with high sensitivity (89%) and specificity (94%) in model-1g that has 4 risk factors compared to other sub-models (1a-1f). All the MPRAS models showed good agreement with the clinician's decision in identifying individuals "at-risk" for myopia progression.

Two-dimensional peripheral refraction in adults

Peripheral refraction has been studied for decades; however, its detection and description are somehow simplistic and limited. Therefore, their role in visual function and refractive correction, as well as myopia control, is not completely understood. This study aims to establish a database of two-dimensional (2D) peripheral refraction profiles in adults and explore the features for different central refraction values. A group of 479 adult subjects were recruited. Using an open-view Hartmann-Shack scanning wavefront sensor, their right naked eyes were measured. The overall features of the relative peripheral refraction maps showed myopic defocus, slight myopic defocus, and hyperopic defocus in the hyperopic and emmetropic groups, in the mild myopic group, and in other myopic groups, respectively. Defocus deviations with central refraction vary in different regions. The defocus asymmetry between the upper and lower retinas within 16° increased with the increase of central myopia. By characterizing the variation of peripheral defocus with central myopia, these results provide rich information for possible individual corrections and lens design.

Additive effects of narrowband light and optical defocus on chick eye growth and refraction

BACKGROUND

In the past decade and during the COVID pandemic, the prevalence of myopia has reached epidemic proportions. To address this issue and reduce the prevalence of myopia and its complications, it is necessary to develop more effective interventions for controlling myopia. In this study, we investigated the combined effects of narrowband lights and competing defocus on eye growth and refraction in chicks, an important step in understanding the potential for these interventions to control myopia. This is the first time these effects have been characterized.

METHODS

Three groups of five-day-old chicks (n = 8 per group) were raised in three different lighting conditions: white, red, and blue for 13 days in a 12/12-h light/dark diurnal cycle. One eye was randomly selected for applications of a dual-power optical lens (- 10 D/ + 10 D, 50∶50), while another eye was left untreated as control. Vitreous chamber depth (VCD), axial length (AL), choroidal thickness (CT) and refractive errors were measured at pre-exposure (D0) and following 3 (D3), 7 (D7), 10 (D10), and 13 days (D13) of light exposure.

RESULTS

Under white light, the dual-power lens induced a hyperopic shift [at D13, mean spherical equivalent refraction (SER), treated vs. control: 4.81 ± 0.43 D vs. 1.77 ± 0.21 D, P < 0.001] and significantly reduced the progression of axial elongation (at D13, change in AL, treated vs. control: 1.25 ± 0.04 mm vs. 1.45 ± 0.05 mm, P < 0.01). Compared to white light alone, blue light alone induced a hyperopic shift (at D13, mean SER, blue vs. white: 2.75 ± 0.21 D vs. 1.77 ± 0.21 D, P < 0.01) and significantly reduced axial elongation (at D13, change in AL, blue vs. white: 1.17 ± 0.06 mm vs. 1.45 ± 0.05 mm, P < 0.01) in control eyes. When comparing all conditions, eyes exposed to blue light plus dual-power lens had the least axial elongation (at D13, change in AL, 0.99 ± 0.05 mm) and were the most hyperopic (at D13, mean SER, 6.36 ± 0.39 D).

CONCLUSIONS

Both narrowband blue light and dual-power lens interventions were effective in inducing a hyperopic shift in chicks, and provided protection against myopia development. The combination of these interventions had additive effects, making them potentially even more effective. These findings support the use of optical defocus interventions in combination with wavelength filters in clinical studies testing their effectiveness in treating myopia in children.

Association between relative peripheral refraction and corresponding electro-retinal signals

PURPOSE

Considering the potential role of the peripheral retina in refractive development and given that peripheral refraction varies significantly with increasing eccentricity from the fovea, we investigated the association between relative peripheral refraction (RPR) and corresponding relative peripheral multifocal electroretinogram (mfERG) responses (electro-retinal signals) from the central to the peripheral retina in young adults.

METHODS

Central and peripheral refraction using an open-field autorefractor and mfERG responses using an electrophysiology stimulator were recorded from the right eyes of 17 non-myopes and 24 myopes aged 20-27 years. The relative mfERG N1, P1 and N2 components (amplitude density and implicit time) of a mfERG waveform were compared with the corresponding RPR measurements at the best-matched eccentricities along the principal meridians, that is at the fovea (0°), horizontal (±5°, ±10° and ± 25°) and vertical meridians (±10° and ± 15°).

RESULTS

The mean absolute mfERG N1, P1 and N2 amplitude densities (nV/deg² ) were maximum at the fovea in both non-myopes (N1: 57.29 ± 14.70 nV/deg² , P1: 106.29 ± 24.46 nV/deg² , N2: 116.41 ± 27.96 nV/deg² ) and myopes (N1: 56.25 ± 15.79 nV/deg² , P1: 100.79 ± 30.81 nV/deg² , N2: 105.75 ± 37.91 nV/deg² ), which significantly reduced with increasing retinal eccentricity (p < 0.01). No significant association was reported between the RPR and corresponding relative mfERG amplitudes at each retinal eccentricity (overall Pearson's correlation, r = -0.25 to 0.26, p ≥ 0.09). In addition, the presence of relative peripheral myopia or hyperopia at extreme peripheral retinal eccentricities did not differentially influence the corresponding relative peripheral mfERG amplitudes (p ≥ 0.24).

CONCLUSIONS

Relative peripheral mfERG signals are not associated with corresponding RPR in young adults. It is plausible that the electro-retinal signals may respond to the presence of absolute hyperopia (and not relative peripheral hyperopia), which requires further investigation.

Ocular Rigidity and Current Therapy

Purpose: Ocular rigidity (OR) is an important biomechanical parameter of the eye accounting for the material and geometrical properties of the corneoscleral shell.Methods: This study used a literature search to review the role of ocular rigidity and the application of potential therapies targeting this parameter in glaucoma and myopia.Conclusion: Biomechanical modeling and improved understanding of the biochemistry, and molecular arrangement of sclera and its constituents have yielded important insights. Recent developments, including that of a non-invasive and direct OR measurement method and improved ocular imaging techniques are helping to elucidate the role of OR in healthy and diseased eyes by facilitating large scale and longitudinal clinical studies. Improved understanding of OR at the initial stages of disease processes and its alterations with disease progression will undoubtedly propel research in the field. Furthermore, a better understanding of the determinants of OR is helping to refine novel therapeutic approaches which target and alter the biomechanical properties of the sclera in sight-threatening conditions such as glaucoma and myopia.

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

BACKGROUND

To investigate the effects of orthokeratology (ortho-k) lenses with aspheric and spherical base curve designs on corneal refractive power (CRP) and peripheral refraction.

METHODS

Children aged 8 to 12 years with myopia between -0.75 D to -4.00 D, astigmatism ≤1.00 D, and corneal astigmatism ≤1.50 D were randomly assigned to the base curve aspheric (BCA) and base curve spherical (BCS) ortho-k lens groups. CRP was assessed for the central 8 mm cornea along horizontal and vertical meridians, and peripheral refraction was measured at 10°, 20°, and 30° along the nasal and temporal retina. Primary measurements included relative corneal refractive power change (RCRPC) and relative peripheral refraction change (RPRC).

RESULTS

The 3-month results of the 33 and 29 subjects (right eye only) in the BCA and BCS groups, respectively, were obtained. Nonsignificant differences were found in the baseline data between the two groups (p > 0.05). At the 3-month follow-up visit, the mean RCRPC in the BCA group (2.08 ± 0.65 D) was significantly greater than that in the BCS group (1.32 ± 0.81 D) (F_1,51 = 25.25, p < 0.001). The BCA group (-1.82 ± 0.65 D) exhibited a larger absolute RPRC than the BCS group (-0.98 ± 0.54 D) (F_1,57 = 33.73, p < 0.001).

CONCLUSIONS

It was found that the BCA ortho-k lens resulted in a more aspheric treatment zone and a more myopic relative peripheral refraction (RPR) along the horizontal meridian. The more myopic RPR was contributed by a more hyperopic central refraction and a more myopic peripheral refraction in the BCA group.

Development and Validation of a Simple Nomogram for Predicting Rapid Myopia Progression in Children with Orthokeratology Management

PURPOSE

To develop and validate an ideal nomogram and an online calculator for predicting rapid myopia progression risk in children managed with orthokeratology (ortho-k).

METHODS

Data of children undergoing ortho-k treatment at Shanghai Children's Hospitals between January 2018 and April 2021 were retrospectively assessed. Potential predictors were screened using univariable analyses and a bidirectional stepwise procedure based on Akaike's information criterion. The final model was constructed using multivariable logistic regression and validated using an internal validation cohort. A nomogram and an online calculator were used to present the final model.

RESULTS

In this retrospective study with 1051 eyes of 560 myopia patients, the training cohort included 735 eyes, and the validation cohort included 316 eyes. Among 11 potential predictors of rapid myopia progression considered, the following four variables identified as independent predictive factors were included in the nomogram: age (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.61-0.79), baseline spherical equivalent (OR, 1.53; 95% CI, 1.31-1.79), pupil diameter (OR, 0.56; 95% CI, 0.32-0.97), and horizontal visible iris diameter (OR, 0.57; 95% CI, 0.33-0.97). The mean concordance statistics for the training and validation cohorts were 0.705 (95% CI 0.664-0.747) and 0.707 (95% CI 0.639-0.774), respectively. The online calculator is publicly available (https://hycalculatoronline.shinyapps.io/dynnomapp/).

CONCLUSION

This study developed a simple-to-use nomogram and online calculator that predicted rapid myopia progression risk in children treated with ortho-k, who will likely benefit from early intervention and improved surveillance.

[Observational Comparison of the Safety and Effectiveness of Myopic Children Wearing Defocus Incorporated Soft Contact Lenses or Orthokeratology Lenses]

Objective

To observe and compare the effectiveness and safety of controlling myopia in children by wearing defocus incorporated soft contact (DISC) lenses or orthokeratology (OrthoK) lenses.

Methods

A total of 75 children who came to our hospital between January 2018 and September 2020 were enrolled for this retrospective study. The DISC group consisted of 30 myopic children (60 eyes) wearing peripheral defocal soft incorporated contact lenses during daytime. There were 10 males and 20 females aged (9.9±1.00) years old in this group and their spherical equivalent refractions were (-2.78±0.70) D. The OrthoK group consisted of 45 myopic children (90 eyes) wearing OrthoK lenses. There were 30 female and 15 males aged (9.67±1.11) and their spherical equivalent refractions were (-2.67±0.71) D. All subjects had previously worn prescription glasses for 12 months or longer before they started wearing contact lenses. The subjects were followed up for 12 months once they started wearing contact lenses. The axial changes and corneal and conjunctival complications of the two groups of myopic children were compared and analyzed.

Results

Myopic children in both groups experienced relatively rapid increase in ocular axial length while they were wearing prescription glasses, with the ocular axial length increase in the prescription-glass-wearing period being (0.34±0.09) mm in the OrthoK group and (0.37± 0.07) mm in the DISC group. In the 12 months of wearing contact lenses, the ocular axial length of children in the OrthoK group increased by (0.18±0.04) mm, while that of the DISC group increased by (0.19±0.05) mm. The increase in ocular axial length was reduced in both groups after the children were switched to the new myopia prevention methods, showing significant difference ( P<0. 05). The two groups using two different contact lenses had similar axial length increase, showing no significant difference ( P>0.05). During the 12-month period while the subjects wore the two types of contact lenses, the incidence of chronic follicular conjunctivitis was 11.20% in the OrthoK group and 20.00% in the DISC group, with that of the DISC group being slightly higher without showing significant difference ( P>0.05). The incidence of grade-1corneal staining was 66.70% in the OrthoK group and 56.70% in the DISC group, and the incidence of grade-2 corneal staining was 17.80% in the OrthoK group and 16.70% in the DISC group. In other words, the OrthoK group had slightly higher findings, but the difference was not significant ( P>0.05). The incidence of contact lens-associated papillary conjunctivitis was 2.20% in the OrthoK group and 10.00% in the DISC group, which was slightly higher than that in the orthokeratology lens group, but the difference was not significant( P>0.05).

Conclusion

Both DISC lenses and OrthoK lenses can effectively control the increase in axial length in myopic children, and their have better effects than those of prescription glasses. The two tyes of contact lenses showed similar effects for controlling axial length increase. Both contact lenses have fewer corneal and conjunctival complications and better safety.

Electroretinogram responses in myopia: a review

The stretching of a myopic eye is associated with several structural and functional changes in the retina and posterior segment of the eye. Recent research highlights the role of retinal signaling in ocular growth. Evidence from studies conducted on animal models and humans suggests that visual mechanisms regulating refractive development are primarily localized at the retina and that the visual signals from the retinal periphery are also critical for visually guided eye growth. Therefore, it is important to study the structural and functional changes in the retina in relation to refractive errors. This review will specifically focus on electroretinogram (ERG) changes in myopia and their implications in understanding the nature of retinal functioning in myopic eyes. Based on the available literature, we will discuss the fundamentals of retinal neurophysiology in the regulation of vision-dependent ocular growth, findings from various studies that investigated global and localized retinal functions in myopia using various types of ERGs.

Visual acuity, near phoria and accommodation in myopic children using spectacle lenses with aspherical lenslets: results from a randomized clinical trial

Objectives

To investigate the short- and long-term effects of myopia control spectacle lenses with highly aspherical lenslets (HAL) and slightly aspherical lenslets (SAL) on visual function and visual quality using data obtained from a randomized controlled clinical trial.

Methods

This was a prospective, randomized, controlled, and double-blinded study; 170 myopic children aged 8–13 years were randomly assigned to the HAL, SAL, or single-vision spectacle lenses (SVL) groups. Distance and near visual acuity (VA) at high (100%) and low (10%) contrast in photopic and scotopic conditions, near phoria, stereoacuity, and accommodative lag, microfluctuations (AMFs), amplitude (AA) were measured after wearing lenses for 10 min, 6 months, and 12 months.

Results

In total, 161 subjects completed all follow-up in 12 months and were included in the analysis. After 10 min of wearing, the HAL and SAL groups had lower scotopic and low-contrast VA than the SVL group (decreased 0.03–0.08 logMAR and 0.01–0.04 logMAR in different VAs in the HAL and SAL groups, respectively, all P < 0.05). The reduction in VA was recovered at 12 months as the HAL and SAL groups exhibited significant VA improvements, and the VA was not different among the three groups (all P > 0.05). The HAL and SAL groups had significantly larger AMFs than the SVL group (HAL vs. SAL vs. SVL: 0.21 ± 0.08 D vs. 0.16 ± 0.05 D vs. 0.15 ± 0.06 D at baseline, 0.19 ± 0.07 D vs. 0.17 ± 0.05 D vs. 0.13 ± 0.07 D at 12 months, all P < 0.05). There were no significant differences in accommodative lag, AA, or phoria between the groups (all P > 0.05). The HAL and SAL groups had reduced stereoacuity compared to the SVL group at baseline (70’ vs. 60’ vs. 50’, P = 0.005), but no difference was observed at 12 months (70’ vs. 70’ vs. 70’, P = 0.11).

Conclusions

HAL and SAL have no significant influence on accommodation and phoria except had larger AMF than SVL. Scotopic VA and low-contrast VA are reduced with short-term HAL and SAL use but recovered to be at same level with the SVL after 1 year of use.

Trial registration Chinese Clinical Trial Registry: ChiCTR1800017683. Registered on 9 August 2018. http://www.chictr.org.cn/showproj.aspx?proj=29789

Multifocal contact lens myopia control: central and peripheral retinal image quality

CLINICAL RELEVANCE

That myopic defocus, even if restricted to the peripheral retina, inhibits eye growth in young monkey eyes has motivated the therapy of myopia control through multifocal contact lens wear in children.

BACKGROUND

To understand how eye-length regulating mechanisms are triggered by light requires knowledge of retinal light spread. That is largely lacking for the multifocal contact lenses used in the therapy because empirical methods identifying just the defocus in dioptres are inadequate.

METHODS

"Through-focus" diffraction computations in contact lens/eye models with typical normal eye parameters, including polychromatic light, the chromatic aberrations and an M-cone phototransduction layer, offer estimates of retinal image spread for a range of viewing distances.

RESULTS

Point- and edge-spread distributions of activation of phototransduction in the central retina show that the addition of multifocal zones produces some veiling for in-focus viewing and substantial improvement of image quality for near targets in the unaccommodated eye. These effects are much reduced in the retinal periphery.

CONCLUSION

Whatever therapeutic value there is in prescribing multifocal contact lenses for myopia control, it is not particularly dependent on the precise configuration of the multifocal zones, nor can it be ascribed to changes in image quality specific to the retinal periphery; its origin is more likely less blur for near targets, reducing the stimulus to accommodation.

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

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

Retinal defocus in myopes wearing dual-focus zonal contact lenses

Purpose

To evaluate the refractive impact of dual‐focus (DF) myopia control contact lenses (CLs) on accommodating young myopic adults.

Methods

Phase 1: accommodative accuracy was assessed in 40 myopic participants. Phase 2: a subset of four subjects who demonstrated accurate accommodation and six who chronically underaccommodated were fitted with single vision (SV, Proclear 1 day) and centre‐distance DF myopia control CLs (MiSight 1 day) with approximately +2.00 D of additional power in two surrounding annular zones. While binocularly viewing high contrast characters at 4.00, 1.00, 0.50, 0.33, 0.25 and 0.20 m, aberrometry data were captured across the central ±30° of the horizontal retina. Local refractive errors were pooled for each area of the pupil covered by the central distance or first annular defocus zone of the DF CLs.

Results

In the “good” accommodator group fitted with SV CLs, accommodative lags were generally absent except at the closest viewing distance (mean errors: −0.09 ± 0.22 D, −0.12 ± 0.26 D, −0.05 ± 0.37 D and +0.38 ± 0.54 D for −2.00, −3.00, −4.00 and −5.00 D target vergences, respectively) but significantly larger in the “poor” accommodating participants (+0.81 ± 0.21 D, +0.97 ± 0.27 D, +1.18 ± 0.39 D, +1.47 ± 0.55 D). For most viewing distances, hyperopic defocus observed in the region of the pupil covered by the first annular zone was replaced with myopic defocus when fitted with the DF CLs. Myopic defocus created by the first annular region was present across the central 30° of the retina.

Conclusions

Some young adult myopes chronically experience high levels of hyperopic defocus when viewing near targets, which was replaced by myopic defocus in the annular part of the pupil covered by the treatment zones when fitted with a centre‐distance myopia control DF CL.

A Quantitative Comparison of Multispectral Refraction Topography and Autorefractometer in Young Adults

Purpose: Purpose of this study is to evaluate the measuring consistency of central refraction between multispectral refraction topography (MRT) and autorefractometry.

Methods: This was a descriptive cross-sectional study including subjects in Sun Yat-sen Memorial Hospital from September 1, 2020, to December 31, 2020, ages 20 to 35 years with a best corrected visual acuity of 20/20 or better. All patients underwent cycloplegia, and the refractive status was estimated with autorefractometer, experienced optometrist and MRT. We analyzed the central refraction of the autorefractometer and MRT. The repeatability and reproducibility of values measured using both devices were evaluated using intraclass correlation coefficients (ICCs).

Results: A total of 145 subjects ages 20 to 35 (290 eyes) were enrolled. The mean central refraction of the autorefractometer was −4.69 ± 2.64 diopters (D) (range −9.50 to +4.75 D), while the mean central refraction of MRT was −4.49 ± 2.61 diopters (D) (range −8.79 to +5.02 D). Pearson correlation analysis revealed a high correlation between the two devices. The intraclass correlation coefficient (ICC) also showed high agreement. The intrarater and interrater ICC values of central refraction were more than 0.90 in both devices and conditions. At the same time, the mean central refraction of experienced optometrist was −4.74 ± 2.66 diopters (D) (range −9.50 to +4.75D). The intra-class correlation coefficient of central refraction measured by MRT and subjective refraction was 0.939.

Conclusions: Results revealed that autorefractometry, experienced optometrist and MRT show high agreement in measuring central refraction. MRT could provide a potential objective method to assess peripheral refraction.

The Effects of Center-near and Center-distance Multifocal Contact Lenses on Peripheral Defocus and Visual Acuity

SIGNIFICANCE

Multifocal contact lenses (MFCLs) are being used clinically for myopia control. Center-distance designs caused myopic changes in defocus across the retina that varied by lens design, whereas the center-near design caused peripheral hyperopic changes. Multifocal lenses caused reductions in low-contrast vision that varied by lens design, affecting visual performance.

PURPOSE

The purpose of this study was to compare changes in defocus with four MFCLs, three center-distance and one center-near.

METHODS

Two cohorts of 25 nonpresbyopic myopic adults were enrolled. The first cohort was fitted with Proclear D and Biofinity D MFCL (center-distance, +2.50 D add), and the second cohort was fitted with NaturalVue MFCL (center-distance) and Clariti 1-Day MFCL (center-near, high add), both in random order. Overrefraction was performed to maximize visual acuity. Cycloplegic autorefraction was performed with each lens and without a lens along the line of sight and at nasal and temporal retinal locations out to 40°. Data were analyzed with repeated-measures ANOVAs with post hoc t tests, when indicated.

RESULTS

Changes in defocus at each location differed between MFCL designs (lens by location; both, P < .001). Clariti 1-Day caused peripheral hyperopic retinal changes (40 and 30° nasal, and 20, 30, and 40° temporal; all, P < .05). NaturalVue MFCL caused myopic changes centrally and hyperopic changes at 40° nasal and 30° temporal (all, P < .05). The remaining center-distance designs caused myopic changes at multiple locations (all, P < .05).

CONCLUSIONS

After overrefraction, the center-near MFCL design caused hyperopic defocus at multiple peripheral locations, which is not hypothesized to slow myopia progression. NaturalVue MFCL caused myopic changes in defocus centrally but hyperopic changes in the far periphery. Biofinity D and Proclear D caused myopic changes in retinal defocus. Further work is warranted to determine whether defocus profile differences between the center-distance designs influence any slowing of myopia progression.

Functional integration of eye tissues and refractive eye development: Mechanisms and pathways

Refractive eye development is a tightly coordinated developmental process. The general layout of the eye and its various components are established during embryonic development, which involves a complex cross-tissue signaling. The eye then undergoes a refinement process during the postnatal emmetropization process, which relies heavily on the integration of environmental and genetic factors and is controlled by an elaborate genetic network. This genetic network encodes a multilayered signaling cascade, which converts visual stimuli into molecular signals that guide the postnatal growth of the eye. The signaling cascade underlying refractive eye development spans across all ocular tissues and comprises multiple signaling pathways. Notably, tissue-tissue interaction plays a key role in both embryonic eye development and postnatal eye emmetropization. Recent advances in eye biometry, physiological optics and systems genetics of refractive error have significantly advanced our understanding of the biological processes involved in refractive eye development and provided a framework for the development of new treatment options for myopia. In this review, we summarize the recent data on the mechanisms and signaling pathways underlying refractive eye development and discuss new evidence suggesting a wide-spread signal integration across different tissues and ocular components involved in visually guided eye growth.

The Correlations between Horizontal and Vertical Peripheral Refractions and Human Eye Shape Using Magnetic Resonance Imaging in Highly Myopic Eyes

The aim of this study was to determine the relationship between relative peripheral refraction and retinal shape by 2-D magnetic resonance imaging in high myopes. Thirty-five young adults aged 20 to 30 years participated in this study with 16 high myopes (spherical equivalent < −6.00 D) and 19 emmetropes (+0.50 to −0.50 D). An open field autorefractor was used to measure refractions from the center out to 60° in the horizontal meridian and out to around 20° in the vertical meridian, with a step of 3 degrees. Axial length was measured by using A-scan ultrasonography. In addition, images of axial, sagittal, and tangential sections were obtained using 2-D magnetic resonance imaging. The highly myopic group had a significantly relative peripheral hyperopic refraction and showed a prolate ocular shape compared to the emmetropic group. The highly myopic group had relative peripheral hyperopic refraction and showed a prolate ocular form. Significant differences in the ratios of height/axial (1.01 ± 0.02 vs. 0.94 ± 0.03) and width/axial (0.99 ± 0.17 vs. 0.93 ± 0.04) were found from the MRI images between the emmetropic and the highly myopic eyes (p < 0.001). There was a negative correlation between the retina’s curvature and relative peripheral refraction for both temporal (Pearson r = −0.459; p < 0.01) and nasal (Pearson r = −0.277; p = 0.011) retina. For the highly myopic eyes, the amount of peripheral hyperopic defocus is correlated to its ocular shape deformation. This could be the first study investigating the relationship between peripheral refraction and ocular dimension in high myopes, and it is hoped to provide useful knowledge of how the development of myopia changes human eye shape.

Repeatability and reproducibility of manual choroidal thickness measurement using Lenstar images in children before and after orthokeratology treatment

PURPOSE

To investigate the repeatability and reproducibility of choroidal thickness measurements using Lenstar images in young myopic children before and after one-month orthokeratology (ortho-k) treatment.

METHOD

Ocular biometry of 39 subjects were performed using the Lenstar 900. The first five measurements with maximum differences of 0.02 mm in axial length in the right eyes were saved and used for measurement of choroidal thickness. Subfoveal choroidal thickness were manually measured by identifying the signals from the retinal pigmented epithelium layer and chorioscleral interface. Repeatability was determined by comparing measurements of the same images made by the same observer on two separate occasions (four weeks apart), while reproducibility was calculated by comparing measurements of the same images made by two independent observers. Data was analysed using intra-class correlation coefficients (ICC) and non-parametric Bland and Altman plots.

RESULTS

The choroidal peaks could not be identified in all five measurements in all subjects. On average, only 71% subjects had at least four definable images. Compared with the use of fewer than four images, reliability using an average of four definable images improved statistically, but remained clinically unacceptable (>10 µm), although pre- and post-ortho-k ICC values were good to excellent for repeatability (0.867 and 0.975, respectively) and excellent and good for reproducibility (0.959 and 0.868, respectively). Non-parametric pre- and post-ortho-k limits of agreement (2.5% and 97.5% percentiles) obtained were -45.8 to 79.3 µm and -30.3 to 9.5 µm, respectively for repeatability, and -29.0 to 33.5 µm and -21.8 to 70.0 µm, respectively for reproducibility.

CONCLUSION

Choroidal thickness measurements using the Lenstar did not show good reliability, despite the high ICC values, non-parametric Bland and Altman plots demonstrated a wide variability of measurement errors. Any changes in subfoveal choroidal thickness, measured by Lenstar, of <80 µm may not represent real changes.

Genetic network regulating visual acuity makes limited contribution to visually guided eye emmetropization

During postnatal development, the eye undergoes a refinement process whereby optical defocus guides eye growth towards sharp vision in a process of emmetropization. Optical defocus activates a signaling cascade originating in the retina and propagating across the back of the eye to the sclera. Several observations suggest that visual acuity might be important for optical defocus detection and processing in the retina; however, direct experimental evidence supporting or refuting the role of visual acuity in refractive eye development is lacking. Here, we used genome-wide transcriptomics to determine the relative contribution of the retinal genetic network regulating visual acuity to the signaling cascade underlying visually guided eye emmetropization. Our results provide evidence that visual acuity is regulated at the level of molecular signaling in the retina by an extensive genetic network. The genetic network regulating visual acuity makes relatively small contribution to the signaling cascade underlying refractive eye development. This genetic network primarily affects baseline refractive eye development and this influence is primarily facilitated by the biological processes related to melatonin signaling, nitric oxide signaling, phototransduction, synaptic transmission, and dopamine signaling. We also observed that the visual-acuity-related genes associated with the development of human myopia are chiefly involved in light perception and phototransduction. Our results suggest that the visual-acuity-related genetic network primarily contributes to the signaling underlying baseline refractive eye development, whereas its impact on visually guided eye emmetropization is modest.

Genome-wide analysis of retinal transcriptome reveals common genetic network underlying perception of contrast and optical defocus detection

BACKGROUND

Refractive eye development is regulated by optical defocus in a process of emmetropization. Excessive exposure to negative optical defocus often leads to the development of myopia. However, it is still largely unknown how optical defocus is detected by the retina.

METHODS

Here, we used genome-wide RNA-sequencing to conduct analysis of the retinal gene expression network underlying contrast perception and refractive eye development.

RESULTS

We report that the genetic network subserving contrast perception plays an important role in optical defocus detection and emmetropization. Our results demonstrate an interaction between contrast perception, the retinal circadian clock pathway and the signaling pathway underlying optical defocus detection. We also observe that the relative majority of genes causing human myopia are involved in the processing of optical defocus.

CONCLUSIONS

Together, our results support the hypothesis that optical defocus is perceived by the retina using contrast as a proxy and provide new insights into molecular signaling underlying refractive eye development.

IMI Accommodation and Binocular Vision in Myopia Development and Progression

The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in accommodation and the consequent alterations in ocular parameters has expanded. This International Myopia Institute white paper reviews the variations in ocular parameters that occur with accommodation and the mechanisms involved in accommodation and myopia development and progression. Convergence is synergistically linked with accommodation and the impact of this on myopia has also been critiqued. Specific topics reviewed included accommodation and myopia, role of spatial frequency, and contrast of the task of objects in the near environment, color cues to accommodation, lag of accommodation, accommodative-convergence ratio, and near phoria status. Aspects of retinal blur from the lag of accommodation, the impact of spatial frequency at near and a short working distance may all be implicated in myopia development and progression. The response of the ciliary body and its links with changes in the choroid remain to be explored. Further research is critical to understanding the factors underlying accommodative and binocular mechanisms for myopia development and its progression and to guide recommendations for targeted interventions to slow myopia progression.

Trends in research related to high myopia from 2010 to 2019: a bibliometric and knowledge mapping analysis

AIM

To evaluate the global trends in and explore hotspots of high myopia (HM) research.

METHODS

This bibliometric analysis was used to reveal the publication trends in HM research field based on the Web of Science Core Collection (WoSCC). VOSviewer version 1.6.13 software was used to analyze the data and construct a knowledge map including the yearly publication number, journals, countries, international collaborations, authors, research hotspots, and intellectual base in HM.

RESULTS

The search engine found 3544 peer-reviewed publications on HM between 2010 and 2019, and the yearly research output substantially elevated over the past decade. China is the top publishing country, and Sun Yat-sen University was the most active academic institution. Jonas JB is the top publishing scientist, and Investigative Ophthalmology and Visual Science (IOVS) was the most productive journal. The highest cited references mainly focused on epidemiology and management. The keywords formed 6 clusters: 1) refractive surgery; 2) etiology and clinical characteristics; 3) the mechanism of eye growth; 4) management for myopic maculopathy; 5) vitrectomy surgical treatment; 6) myopia-associated glaucoma-like optic neuropathy.

CONCLUSION

The evaluation of development trends based on the data extracted from WoSCC can provide valuable information and guidance for ophthalmologists and public health researchers to improve management procedures in HM field.

The long-term observation in Chinese children with monocular myelinated retinal nerve fibers, myopia and amblyopia

BACKGROUND

The syndrome of monocular myelinated retinal nerve fibers (MRNF), myopia and amblyopia threatens visual development of infants and young children. The efficacy of part-time occlusion therapy remains controversial, and the long-term prognosis of the syndrome remains unclear.

METHODS

Ten children (4.40±2.22 years, 4 boys and 6 girls) with monocular MRNF, myopia and amblyopia were recruited. Both the affected eyes (treatment group) and the fellow eyes (control group) underwent routine ophthalmic examinations, including AL, cycloplegic refraction, best-spectacles-corrected distance visual acuity (BSCDVA), cover test, simultaneous perception, corneal curvature, anterior segment and fundus examinations. Refractive error was corrected by either spectacles or rigid gas permeable (RGP) contact lenses. Part-time occlusion therapy was employed for amblyopia treatment. The retinal characteristics were examined only on the final visit with a Fourier-domain optical coherence tomography (FD-OCT). The speed of myopia progression and axial elongation were calculated. Statistical analysis was performed using SPSS 20 software. Cut-off P values were 0.05.

RESULTS

On the final visit, six children had normal simultaneous perception but three had strabismus. The mean AL and spherical equivalent (SE) values of the affected eyes were 28.05±1.59 mm and -12.60±4.20 D, respectively, while those of the fellow eyes were 23.67±1.13 mm and -0.66±1.99 D, respectively. AL and SE were significantly different over time and between groups (P<0.0001), but no time*group interaction effect (P>0.05) was observed. The differences in the corneal curvature, mean speed of myopia progression, axial elongation, foveal thickness and parafoveal thickness between the two groups were not significant (P>0.05). However, the perifoveal thickness in the affected eyes was significantly higher than that of the control eyes (P=0.047). In the treatment group, the occlusion dosage positively correlated with the final BSCDVA (R=0.764, P=0.016) but did not correlate with the speed of myopia progression or axial elongation (both P values >0.05).

CONCLUSIONS

The affected eyes have longer AL, severer myopia and thicker perifoveal retina when compared with the fellow eyes. Both the affected and the fellow eyes have similar speed of myopia progression as well as that of axial elongation.

Two-Dimensional, High-Resolution Peripheral Refraction in Adults with Isomyopia and Anisomyopia

Purpose

The purpose of this study was to investigate the two-dimensional peripheral refraction in fellow eyes of patients with isomyopia and anisomyopia.

Methods

Sixty-eight young adults were recruited, including 25 isomyopes with interocular differences (IODs) of foveal refraction < 1.00 D and 43 anisomyopes with IOD > 1.50 D. Peripheral refraction across an area of the visual field of 60° × 36° with a resolution of 1° was measured using a custom-made Hartmann-Shack wavefront sensor. The retinal area was divided into 3 × 3 zones for comparison between the fellow eyes.

Results

There was no difference of refraction in all corresponding zones between the fellow eyes in the isomyopic group (all P > 0.05). The IODs between more myopic (MM) eyes and less myopic (LM) eyes in the anisomyopic group ranged from −1.40 to approximately −2.46 D (all P <0.001), which was flagged in the center and attenuated in peripheral zones by varied magnitudes. In the stratification analysis for different levels of anisomyopia, the nasal retina first presented significant relative hyperopic shifts compared to the center, followed by the temporal retina. In contrast, the superior and inferior periphery only differed from the center when the central IOD was greater than 3.00 D.

Conclusions

The two-dimensional peripheral refraction patterns showed a mirror symmetry between the fellow eyes of a patient with isomyopia. However, in the anisomyopic group, peripheral refraction showed significantly relative hyperopic shift when compared with the center and developed with a varied rate in different areas. These findings may indicate an asymmetrical variation in the peripheral refraction patterns during myopia progression.

Eccentricity-dependent effects of simultaneous competing defocus on emmetropization in infant rhesus monkeys

Dual-focus lenses that impose simultaneous competing myopic defocus over the entire visual field produce axial hyperopic shifts in refractive error. The purpose of this study was to characterize the effects of eccentricity on the ability of myopic defocus signals to influence central refractive development in infant monkeys. From 24 to 152 days of age, rhesus monkeys were reared with binocular, dual-focus lenses that had central, zero-powered zones surrounded by alternating concentric annular power zones of +3D and zero power. Between subject groups the diameter of the central, zero-powered zone was varied from 2 mm to 8 mm in 2 mm steps (+3D/pl 2 mm, n = 6; +3D/pl 4 mm, n = 6; +3D/pl 6 mm, n = 8, or + 3D/pl 8 mm, n = 6). For the treatment lens with 2, 4, 6 and 8 mm central zones, objects at eccentricities beyond 11°, 16°, 19° and 23°, respectively, were imaged exclusively through the dual-power peripheral zones. Refractive status (retinoscopy), corneal power (keratometry) and axial dimensions (ultrasonography) were measured at two-week intervals. Comparison data were obtained from monkeys reared with binocular, single-vision +3D full-field lenses (+3D FF, n = 6) and 41 normal control monkeys reared with unrestricted vision. At the end of the rearing period, with the exception of the +3D/pl 8 mm group (median = +3.64 D), the ametropias for the other lens-reared groups (medians: FF = +4.39 D, 2 mm = +5.19 D, 4 mm = +5.59 D, 6 mm = +3.50 D) were significantly more hyperopic than that for the normal monkeys (+2.50 D). These hyperopic errors were associated with shallower vitreous chambers. The key finding was that the extent and consistency of these hyperopic ametropias varied with the eccentricity of the dual-focus zones. The results confirm that myopic defocus in the near periphery can slow axial growth, but that imposed defocus beyond about 20° from the fovea does not consistently alter central refractive development.