This study investigated early temporal dynamics of ocular compensation to imposed astigmatic blur, specifically anterior segment alterations in a chick model. Fifty-four chickens were equally randomized to treatment or control groups at post-hatching day 5 (baseline, T0). Crossed-cylindrical lens (+4.00 DS/-8.00 DC) was used to induce astigmatic blur on the right eye for two weeks: With-the-rule (WTR, axis 90°) and Against-the-rule (ATR, axis 180°) astigmatism. Ocular axial dimensions and objective refraction were measured daily for the first four days (T0-T3), and at one (T7) and two weeks (T14). Corneal topography was measured at T3, T7 and T14. Our results showed that chicks treated with crossed-cylindrical lenses developed significantly higher refractive astigmatism compared to the control group (all p < 0.01), plateauing within two days. Corneal astigmatism diverged over two weeks, increasing in the WTR group but decreasing in the ATR groups, while internal astigmatism showed opposite trends. Critically, anterior segment changes emerged by T3: the ATR group exhibited a significantly deeper anterior chamber (T3: p = 0.034), and both treatment groups showed significantly thinner crystalline lenses (ATR: T2, p = 0.008; T3, p = 0.007; WTR: T3, p = 0.043) compared to controls. These changes persisted throughout the treatment. To conclude, refractive astigmatism compensated rapidly (plateauing within two days) in response to astigmatic blur, while corneal astigmatism exhibited divergent changes over two weeks. The persistent anterior segment alterations-lens thinning and anterior chamber deepening-demonstrate a key compensatory role for anterior ocular structures beyond corneal plasticity alone.

Progressive addition lenses (PALs) introduce spatially varying blur, including blur associated with unwanted astigmatism, but the perceptual consequences of this blur remain poorly understood. We tested whether short-term PAL wear was associated with spatially localized changes in blur sensitivity corresponding to regions of unwanted optical blur or with changes that were more broadly distributed across the visual field. Seven myopic presbyopes with astigmatism and no prior PAL experience were tested before and after two weeks of PAL wear. Blur sensitivity was measured using a two-alternative forced-choice comparison task at randomized visual-field locations, including the fovea, and 7.5$$^\circ$$ and 25$$^\circ$$ eccentricities across eight meridians. Threshold-versus-reference functions measured across five reference blur levels were fitted to estimate intrinsic blur. Linear mixed-effects models showed that two weeks of PAL wear significantly increased blur thresholds and intrinsic blur, indicating reduced blur sensitivity. However, these adaptation-related changes depended on eccentricity, with significant increases observed at 25$$^\circ$$ eccentricity (p < 0.001), and not at 7.5$$^\circ$$ eccentricity or the fovea. Among the seven participants who completed both assessments, short-term PAL wear was therefore associated with increased blur thresholds and intrinsic blur at 25$$^\circ$$ eccentricity. The absence of statistically detectable meridional dependence suggests that this peripheral change was broadly distributed across the tested locations rather than confined to a specific meridian.

Background:The myopia rate has increased rapidly worldwide, yet evidence regarding the association between dietary factors and myopia remains limited. This study assessed the association between dietary patterns and myopia among children and adolescents. Methods:This study used the Child and Adolescent Research of Eye data between August and October 2022. Myopia was defined based on uncorrected visual acuity and noncycloplegic refraction. Dietary assessment was parent-reported via a food frequency questionnaire (FFQ). Principal component analysis was used to extract dietary patterns. Binary logistic regression was used to evaluate the association between dietary patterns and myopia. Results:A total of 24,797 participants were included in the analysis. Controlling for confounders, the highest adherence to nuts-tubers vegetables pattern (characterized by high intake of nuts, tubers vegetables, legumes, whole grains, and aquatic products) was associated with a decreased risk of myopia compared with the lowest adherence (odds ratio [OR] = 0.933, 95% confidence interval [CI]: 0.872 to 0.999, p = 0.046). Conversely, the highest adherence to snacks pattern (characterized by high intake of fried and barbecued, fast foods and savoury snacks, sugar-sweetened beverages, desserts, and processed meats) was associated with an increased risk of myopia (OR = 1.083, 95% CI: 1.012 to 1.158, p = 0.021). Conclusions:These findings indicate a link between dietary patterns and myopia in children and adolescents. Dietary modification could be a potential public health measure for the primary prevention of childhood myopia.

Visual fatigue is becoming increasingly prevalent globally, while universally accepted definitions and standardized diagnostic criteria remain lacking. This study aims to develop consensus-based recommendations on the definition, diagnostic criteria, core symptoms, risk factors, and assessment of visual fatigue, using a modified Delphi process to support standardized clinical and epidemiologic practice. A modified Delphi process was conducted with an international panel of experts in optometry, ophthalmology, and related disciplines. Two rounds of questionnaires were used to generate candidate definitions, diagnostic criteria, symptoms, risk factors, assessment methods and management principles. A subsequent hybrid meeting was held to discuss unresolved items and consolidate the final recommendations. Of 20 experts invited, 14 participated in the panel (response rate 70

This study compares Area-Based Analysis (ABA) and Ring-Based Analysis (RBA) for detecting corneal changes in a chick model of experimental astigmatism. Both methods were first validated using steel balls with known radii, demonstrating comparable keratometric values (p ≥ 0.14) and good accuracy, with mean deviations of approximately 0.50 D or less across SteepK, FlatK, MeanK, cylindrical power (CYL), and J0 and J45 astigmatic components. The methods were then applied to chicks randomly assigned to monocularly imposed hyperopic with-the-rule (H-WTR, n = 12) or against-the-rule (H-ATR, n = 10) astigmatism groups, with six untreated Control. Compared to RBA, ABA consistently showed significantly higher within-eye repeatability for all parameters (p < 0.001). In treated eyes, ABA detected the CYL differences in both H-ATR (p = 0.017) and H-WTR (p < 0.001) groups versus Control, whereas RBA only identified differences in H-WTR (p = 0.03) versus Control. Furthermore, ABA yielded significantly steeper SteepK, FlatK, and MeanK (p < 0.001), likely due to differences between methods in sampling the radial curvature gradient of the aspheric cornea, whereas the more negative J0 and J45 values (p ≤ 0.001) reflected method-dependent shifts in astigmatic axis. When comparing interocular differences (treated right eye minus untreated left eye), ABA uniquely identified treatment-induced CYL changes in H-WTR compared to H-A TR and Control (p ≤ 0.034). These results underscore that ABA showed higher repeatability and statistical sensitivity for detecting subtle corneal astigmatic changes, establishing it as an effective analytical method for experimental astigmatism research in chicks.

PURPOSE:To evaluate the performance of a three-dimensional convolutional neural network (3D CNN) in detecting forme fruste keratoconus (FFKC). METHODS:A total of 415 anonymized corneal dynamic videos were collected for this study. The video dataset consisted of 150 patients with FFKC (150 videos) and 265 normal patients (265 videos). These patients underwent comprehensive ocular examinations, including slit lamp, Pentacam (Oculus Optikgeräte GmbH), and Corvis ST (Oculus Optikgeräte GmbH), and were classified by corneal experts. A 3D CNN-based algorithm was developed to establish a FFKC detection model. The performance of the model was evaluated using metrics such as accuracy, area under the receiver operating characteristic curve (AUC), confusion matrices, and F1 score. Gradient-weighted class activation mapping (Grad-CAM) was used to observe the regions that the model attended to. RESULTS:In the test dataset, the model achieved an accuracy of 87.95% in identifying FFKC. The ResNet3D-AUC was 0.95 with a cut-off value of 0.49, and the F1 value was 0.85. The sensitivity was 83.33% and the specificity was 90.57%. CONCLUSIONS:Combining 3D CNN with Corvis ST corneal dynamic videos provides a new method for distinguishing between FFKC and normal corneas. This could offer valuable clinical insights and recommendations for detecting FFKC. Nevertheless, the generalizability of the model is still a concern, and external validation is required prior to its clinical implementation. [J Refract Surg. 2025;41(4):e356-e364.].

Large language models (LLMs) show promise for tailored healthcare communication but face challenges in interpretability and multi-task integration particularly for domain-specific needs like myopia, and their real-world effectiveness as patient education tools has yet to be demonstrated. Here, we introduce ChatMyopia, an LLM-based AI agent designed to address text and image-based inquiries related to myopia. To achieve this, ChatMyopia integrates an image classification tool and a retrieval-augmented knowledge base built from literature, expert consensus, and clinical guidelines. Myopic maculopathy grading task, single question examination and human evaluations validated its ability to deliver personalized, accurate, and safe responses to myopia-related inquiries with high scalability and interpretability. In a randomized controlled trial (n=70, NCT06607822), ChatMyopia significantly improved patient satisfaction compared to traditional leaflets, enhancing patient education in accuracy, empathy, disease awareness, and patient-eyecare practitioner communication. These findings highlight ChatMyopia's potential as a valuable supplement to enhance patient education and improve satisfaction with medical services in primary eye care settings.

Large language models (LLMs) show promise for tailored healthcare communication but face challenges in interpretability and multi-task integration, particularly for domain-specific needs such as myopia, and their real-world effectiveness as patient education tools has yet to be demonstrated. Here, we introduce ChatMyopia, an LLM-based AI agent to address text- and image-based inquiries related to myopia. ChatMyopia integrates an image classification tool and a retrieval-augmented knowledge base built from literature, expert consensus, and clinical guidelines. Myopic maculopathy grading task, single question examination, and human evaluations validated its ability to deliver accurate and safe responses with high scalability and interpretability. In a randomized controlled trial, it significantly improved patient satisfaction compared to traditional leaflets, enhancing patient education in accuracy, empathy, disease awareness, and communication with eye care practitioners. These findings highlight ChatMyopia's potential as a valuable supplement to enhance patient education and improve satisfaction with medical services in primary eye care settings.

Introduction:To validate a novel smartphone-based approach for subjective refraction, specifically for myopia screening, offering a cost-effective and accessible tool for at-home vision assessment. Methods:A total of 230 healthy volunteers, encompassing 460 eyes, aged between 7 and 40 years (mean ± SD: 21.04 ± 7.76), and exhibiting refractive error (RE) ranging from -6.25 to +0.50 diopter (D), were deemed eligible subjects in this research. Subjective refraction assessments were conducted on all subjects, involving both the conventional phoropter examination by experienced optometrists which served as the clinical gold-standard, and the smartphone-based methodology. During smartphone measurement, the screen was gradually moved toward the eye until achieving clear differentiation of the 'E' optotypes and the astigmatic dial. The eye-to-smartphone screen distances (ESD) were calculated based on the image of iris diameter (ID) acquired by the front-facing camera of the smartphone. Applying the definitions of the far point and the rule of thirty, this allowed for the computation of sphere (S), cylinder (C), and astigmatism axis (α) values. The concordance between the two methods was assessed by establishing the Limits of Agreement (LOAs), which were calculated as the mean difference ± 1.96 times the standard deviation of the differences. Results:The smartphone-based screening technique showed that it closely matched the gold-standard subjective refraction used in clinical practice. The LOAs for S, C, and spherical equivalent refraction (SER) were 0.11 ± 0.89 D, -0.03 ± 0.82 D, and 0.10 ± 0.89 D, respectively. The average deviation in measuring the α was 4.72°, with 64.35% of deviations falling within the ±15° range. Additionally, the technique demonstrated impressive areas under the receiver operating characteristic curve (AUC) of 0.973 for the range of -3.00 D < SER ≤ 0.00 D and 0.986 for the range of -6.00 D < SER ≤ -3.00 D. Discussion:The innovative vision screening through smartphones can expand access to measuring RE, especially in home. The study confirms the validity of an innovative vision-screening approach for myopia. Its effectiveness and accessibility make it a valuable tool for opportunistic or large-scale myopia screening programs.

Purpose:To determine whether localized retinal exposure to astigmatic blur is sufficient to drive compensatory changes in refractive and corneal astigmatism in developing chick eyes. Methods:One hundred and thirty-six chicks were randomly assigned to nine groups combining three visual field conditions (full, horizontal, or vertical) and three lens treatments: with-the-rule (WTR) astigmatism (+2.00/-4.00 × 90), against-the-rule (ATR) astigmatism (+2.00/-4.00 × 180), or control (plano lens). Objective refraction and A-scan ultrasonography were measured at baseline (post-hatch day 5) and after 7 days of lens treatment, at which time corneal topography was also assessed. Data were analyzed using interocular differences (treated right eye minus untreated left eye) with two-way ANOVA. Results:Exposure to astigmatic blur induced significant compensatory changes in both refractive and corneal astigmatism, regardless of visual field extent. WTR blur elicited greater compensatory astigmatism than ATR blur (mean difference = 1.20 ± 0.16 DC, P < 0.001), with both conditions showing significant compensation compared to controls (P < 0.001). Visual field condition had no significant effect on astigmatic compensation (P ≥ 0.19). In contrast, spherical ametropia development was influenced by visual field exposure, with partial-field conditions inducing mild myopic shifts and deeper anterior chambers compared to full-field exposure (P < 0.001). Conclusions:Localized retinal exposure to astigmatic blur is sufficient to drive compensatory changes in both refractive and corneal astigmatism, indicating that local retinal mechanisms can independently guide astigmatism compensation. In contrast, spherical refractive development appears to be modulated by the extent of visual field exposure.

Purpose:The study aimed to develop a predictive model for refraction after cycloplegia by leveraging non-cycloplegia ocular parameters and focusing on lens-related features. Methods:A total of 153 children 4 to 15 years old were enrolled in this study. This study randomized gender distribution. Sex, age, intraocular pressure (IOP), refraction before and after cycloplegia, and optical biometry (OB) parameters were collected. Four prediction models for spherical refraction were developed: a control group without lens-related features and three experimental groups incorporating lens-related features. Features such as lens diopter, anterior surface curvature radius, and lens thickness played significant roles. The models were evaluated using statistical measures: mean square error (MSE), Root mean square error (RSME), Mean absolute error (MAE) and r-square (r2). Least absolute shrinkage and selection operator (LASSO) regression and the L1 regularization term were used for feature screening and machine learning for extreme gradient enhancement. The extreme gradient boosting (XGBoost) method was used to develop the model. Results:The predictive model incorporating lens-related features demonstrated superior performance in estimating refraction after cycloplegia compared to the model without such features. Among the models with lens-related features, the IOL of contact lens algorithm (IOLcl) group exhibited the highest efficacy, boasting an r2 of 0.964, MSE of 0.241, RMSE of 0.472, and MAE of 0.307. Conclusions:The study provided valuable insights into developing a robust predictive model for refraction after cycloplegia, emphasizing the importance of lens-related features and the morphological changes in the crystalline lens during accommodation. Translational Relevance:This predictive model has potential advantages in avoiding complications associated with cycloplegia and can be widely applied for clinic vision screening in optometry.

PURPOSE:This study aimed to determine the prevalence of myopia among children and adolescents aged 6-16 years during COVID-19 pandemic in Tianjin, China. METHODS:This was a cross-sectional study using data from the Tianjin Child and Adolescent Research of Eye between March and June in 2021. A total of 909 835 children and adolescents aged 6-16 years from 1348 primary and secondary schools in Tianjin, China were recruited. Prevalence of myopia with 95% CIs was described in different regions, sexes and ages. The regions-standardised prevalence rate and chain growth rate of myopia in different ages were described the characteristics of myopia. RESULTS:A total of 864 828 participants (95.05% participation rate) were included in the analysis. The age range was 6-16 with a mean age of 11.50±2.79 years. The overall prevalence of myopia was 54.71% (95% CI 54.60% to 54.81%). The prevalence of myopia was 57.58% (95% CI 57.43% to 57.73%) for girls and 52.05% (95% CI 51.91% to 52.20%) for boys. Students living in the six central districts had the highest prevalence of moderate myopia (19.09% (95% CI 19.01% to 19.17%)) and high myopia (5.43% (95% CI 5.39% to 5.48%)). The regions-standardised prevalence of myopia was increased by age and the highest chain growth rate of myopia was up to 47.99% at 8 years. CONCLUSIONS:The prevalence of myopia in Tianjin is high during COVID-19 pandemic. The progression of myopia started to increase dramatically at 8 years, and the increasing slowed down at 14 years. For policy-makers, intervention in the lower age groups may be important to control myopia progression.

Purpose:To investigate the progression rates of axial length (AXL) among school-age children with baseline astigmatism and spherical ametropia. Methods:Annual vision screenings were conducted at seven schools in Tianjin, China, from 2018 to 2022. Ocular biometry and non-cycloplegic autorefraction were collected. Children 5 to 16 years old without any myopia interventions were included and categorized by their baseline astigmatism magnitude (control, low, or high) and axis orientation (with the rule [WTR], against the rule [ATR], or oblique). Additionally, children were classified by baseline spherical ametropia (compound hyperopic, compound myopic, or other). Annual AXL progression rates of right eyes were calculated using regression models and compared across different types of astigmatism and spherical ametropia. Results:A total of 10,732 Chinese children (baseline age, 9.26 ± 2.42 years; follow-up duration, 2.63 ± 1.01 years) were included and divided into a younger cohort (age < 11 years; n = 7880) and an older cohort (age ≥ 11 years; n = 2852). Across both age groups and all astigmatism magnitudes, ATR astigmatism exhibited the most rapid AXL progression, followed by oblique and WTR astigmatism. Two-way ANCOVA of the combined cohort revealed that both high-magnitude and ATR astigmatism were significantly associated with AXL progression (P ≤ 0.018). However, the impact of astigmatism on AXL progression varied depending on baseline spherical ametropia, as high-magnitude and ATR astigmatism increased AXL progression in compound myopic eyes but decreased progression in compound hyperopic eyes. Conclusions:Both baseline magnitude and axis orientation of astigmatism are significantly associated with axial elongation in children. However, these associations may vary with spherical ametropia, with differential patterns being observed between compound hyperopic and myopic eyes.

Form deprivation (FD) is a widely employed experimental paradigm, typically used to induce unilateral myopia in animal models. This model is weakened by potential influence upon the FD eye from vision in the freely-viewing contralateral eye, which could be eliminated by imposing FD in both eyes; but while a few previous studies have explored the feasibility of inducing bilateral FD in chicks, substantial discrepancies in treatment outcomes were noted. Consequently, this study aimed to establish a bilateral FD myopia model in chicks, with validation by investigating the associated ocular growth patterns, feeding, and social behavior. Six-day-old chicks were treated with bilateral (n = 21) or unilateral (n = 10) FD for 12 days; the fellow untreated eyes in the unilateral FD group served as controls. Refractive error, corneal power, and ocular axial dimensions were measured at 4-day intervals after the onset of form deprivation, with a Hartinger refractometer, a custom-made videokeratography system, and a high-resolution A-scan ultrasonographer, respectively. Body weight was monitored to assess the chick's physical development. Our results showed that birds treated with bilateral FD grew as robustly as the unilaterally form-deprived chicks, with similar or slightly heavier body weights and mortalities. Unilateral FD induced significantly higher myopia in the treated eye, with stronger corneal power, deeper anterior and vitreous chambers, and longer axial length. Moreover, either bilaterally or unilaterally FD eyes developed similar refractive error (bilateral FD, left: -28.03 ± 9.06 D, right: -28.44 ± 9.45 D; unilateral FD: -29.48 ± 8.26 D) and ocular biometric changes; but choroidal thickness was thicker in bilaterally FD eyes, rather than thinner as in unilaterally FD eyes. In addition to the highly synchronized (symmetrical, parallel) development reported previously in bilateral FD, we found in this study that the correlations between bilaterally form-deprived eyes were highest for ocular biometric parameters directly contributing to myopia development, including corneal power (r = 0.74 to 0.93), anterior chamber depth (r = 0.60 to 0.85), vitreous chamber depth (r = 0.92 to 0.94), and axial length (r = 0.90 to 0.96). The remarkably synchronized growth pattern confirmed the feasibility of the bilateral FD paradigm for future research on myopia.

This study explores whether children’s refractive errors and visual behaviors reverted to pre-COVID-19 levels a year after normal schooling resumed in Hong Kong as well as the impact of corneal and internal astigmatism on refractive astigmatism development. Vision survey data and questionnaire results collected in 2022 (n = 119) and 2020 (n = 173) were compared. Cross-sectional data showed similar proportions of astigmatism (cylindrical power ≥ 0.75 D) in the 2020 (49.1%) and 2022 cohorts (55.5%). Despite a 0.28 D increase in corneal astigmatism, a compensatory 0.24 D increase in internal astigmatism of opposite direction kept refractive astigmatism relatively stable. The questionnaire data showed that children spent an additional 0.5 h/day outdoors on weekends post-resumption of normal schooling but engaged in more near-work activities, especially non-screen near-work, by approximately 1 h/day on both weekdays and weekends. These findings were supported by longitudinal data from 72 children who participated in both surveys. This study highlights the significant role of corneal and internal astigmatism in refractive astigmatism changes. Despite the return to in-person classes, children’s total near-work time increased and astigmatism remained high. These findings underscore the need for comprehensive strategies to reduce the high environmental risks for refractive error development in children.

Aims/Purpose: Myopia is a leading cause of correctable and preventable vision loss worldwide, but the relationship between myopia development and growth of the anterior segment, particularly the cornea, has not been well established. This study aims to investigate whether experimental induction of myopia influences corneal structures in animals. Methods: Ten chicks were unilaterally form deprived by covering their right eyes with translucent diffusers at post‐hatching day 6 (P6). Refractive state, corneal shape, and ocular axial dimensions were measured at 4‐day intervals until P18 using a Hartinger refractometer, a custom‐made videokeratography system, and an A‐scan ultrasonographer, respectively. Parameters in treated vs control eyes were compared at the end of treatment. Repeated one‐way ANOVA was used for statistical analysis, and all parameters were expressed as mean ± SD. Results: At the end of treatment, form‐deprived eyes were myopic (−29.48 ± 8.26D vs. ‐0.61 ± 0.32D) and axially elongated (11.15 ± 0.55 mm vs. 9.51 ± 0.20 mm). At baseline (P6), treated and fellow contralateral eyes had similar corneal power (132.22 ± 6.37D vs. 132.64 ± 5.48D, p = 0.86) and thickness (167.93 ± 6.80 μm vs. 166.43 ± 7.27 μm, p = 0.63), but at P18 form‐deprived eyes had slower corneal flattening and thickening, resulting in significantly steeper (117.73 ± 5.03D vs. 113.22 ± 3.44D, p < 0.05) and thinner corneas (176.80 ± 7.52 μm vs. 192.35 ± 5.62 μm, p < 0.001) than fellow contralateral eyes. Repeated measures correlation analysis further indicated that axial elongation from P6 to P18 was significantly associated with corneal steepening (r rm = 0.77, p < 0.001) and thinning (r rm = −0.69, p < 0.001). Conclusions: This study provides insights into the impact of form deprivation myopia on corneal structures in juvenile animals. Specifically, the corneas of form‐deprived eyes were steeper and thinner because the natural corneal flattening and thickening processes were decelerated by treatment. Further studies are warranted to reveal the mechanisms responsible for this association between development of refractive error and corneal structure.