The influence of variations in ocular biometric and optical parameters on differences in refractive error

PURPOSE

To present a paraxial method to estimate the influence of variations in ocular biometry on changes in refractive error (S) at a population level and apply this method to literature data.

METHODS

Error propagation was applied to two methods of eye modelling, referred to as the simple method and the matrix method. The simple method defines S as the difference between the axial power and the whole-eye power, while the matrix method uses more accurate ray transfer matrices. These methods were applied to literature data, containing the mean ocular biometry data from the SyntEyes model, as well as populations of premature infants with or without retinopathy, full-term infants, school children and healthy and diabetic adults.

RESULTS

Applying these equations to 1000 SyntEyes showed that changes in axial length provided the most important contribution to the variations in refractive error (57%-64%), followed by lens power/gradient index power (16%-31%) and the anterior corneal radius of curvature (10%-13%). All other components of the eye contributed <4%. For young children, the largest contributions were made by variations in axial length, lens and corneal power for the simple method (67%, 23% and 8%, respectively) and by variations in axial length, gradient lens power and anterior corneal curvature for the matrix method (55%, 21% and 14%, respectively). During myopisation, the influence of variations in axial length increased from 54.5% to 73.4%, while changes in corneal power decreased from 9.82% to 6.32%. Similarly, for the other data sets, the largest contribution was related to axial length.

CONCLUSIONS

This analysis confirms that the changes in ocular refraction were mostly associated with variations in axial length, lens and corneal power. The relative contributions of the latter two varied, depending on the particular population.

UCI EyeMobile Exam Findings from School Children Following on-Site Screening

Purpose

Uncorrected refractive errors (REs) and amblyopia can lead to visual impairment with deleterious effects on quality of life and academic performance. Early detection and treatment by community vision care programs, such as the UCI EyeMobile for Children, can aid in addressing preventable vision loss.

Methods

A total of 5074 children between the ages of 3 and 10 years were screened at 153 locations, including preschools, head start programs, and elementary schools within Orange County (OC), California (CA). Subsequently, 1024 children presented for comprehensive eye examinations. A retrospective analysis of all examined children was conducted, determining the frequency and severity of REs and amblyopia and the spectacle prescription rate by age. Propensity score matching analysis evaluated the effect of median household income on RE and amblyopia frequency.

Results

Among those who failed initial screening and were subsequently examined, significant rates of REs and amblyopia were detected: myopia (24.4%), hyperopia (35.4%), astigmatism (71.8%), anisometropia (8.9%), amblyopia (7.0%), and amblyopia risk (14.4%). A majority (65.0%) of those examined received prescription spectacles from UCI EyeMobile, with around a third requiring a new or updated prescription. The frequency of REs and amblyopia and the spectacle prescription rate were uniform across OC congressional districts. Myopia and amblyopia risk was positively and negatively associated with household income, respectively.

Conclusion

The UCI EyeMobile for Children serves as a vital vision care program, providing free vision screening, comprehensive eye examinations, and spectacles. A significant number of children required examination, and a high frequency of REs and amblyopia were detected in examined children, with subsequent provision of prescription spectacles to most children.

The Myopia Prevalence and Association With Physical Activity Among Primary School Students Aged 6-12 Years: A Cross-Sectional Study in Tianjin, China

Purpose

This study aimed to investigate the prevalence of myopia and determine the association between physical activity and risk of myopia among primary school students in Tianjin, China.

Methods

A cross-sectional study was conducted among subjects from nine primary schools. All of the subjects underwent visual acuity and spherical equivalent (SE) with noncycloplegic autorefraction measurement. Myopia was defined as an SE refraction ≤-0.50D and an uncorrected visual acuity <5.0 in either eye. Physical activity was measured via the Physical Activity Questionnaire for Children. Data were analyzed using the Pearson χ2 test and binary logistic regression. Stratification analysis by sex was also performed.

Results

A total of 2976 participants (1408 boys and 1568 girls) aged six to 12 years (mean age 8.82 years) were included in this study. The overall prevalence of myopia was 52.92%. When stratified according to physical activity, myopia prevalence significantly decreased with increasing physical activity levels (χ2 trend test = 127.63, P < 0.001). In the binary logistic regression analysis, after adjusting for age, sex, and school region, the odds ratio for the association between physical activity and myopia was 0.762 (95% confidence interval, 0.675-0.862, P < 0.001). When stratified by sex, the significant statistical association between physical activity and myopia both can be found in two groups (P < 0.05).

Conclusions

Higher levels of physical activity were independently associated with decreased risk of myopia. The significant reverse statistical association between physical activity and myopia can be found in male or female groups.

Translational Relevance

Taking part in physical activities may be an effective way to reduce the prevalence of myopia.

Prediction of Visual Acuity in Pseudophakic Cataract Population Based on Residual Refraction

PURPOSE

The purpose of the study was to design a simple, handy prediction for the effect of spherical and cylindrical refractive error on the visual acuity degradation at different distances and validate this model on a clinical dataset.

METHODS

This study examined 70 eyes from 35 patients' post-cataract surgery with aberration-free intraocular lenses. Biometric and corneal data were analysed, and subjective refraction and visual acuity were evaluated by two experienced optometrists. The study computed the spherical equivalent (SEQ), and defocus equivalent via vector addition (DEQ vec), as the sum of absolute values (DEQ abs). Predictive models were developed using univariate regression, with confidence intervals (BCa 95%) calculated through non-parametric bootstrapping (10,000 cycles).

RESULTS

Various calculated equivalents included -0.44 D for spherical equivalent (SEQ), 0.70 D for defocus equivalent based on vector calculation (DEQ vec), and 0.89 D for defocus equivalent based on absolute values (DEQ abs). Uncorrected and corrected visual acuity averaged 0.07 logMAR and -0.04 logMAR, respectively. The absolute defocus equivalent (DEQ abs) exhibited the smallest confidence interval (BCa 95%) at 0.07.

CONCLUSION

The defocus equivalent based on the addition of absolute values (DEQ abs) emerged as the most practical predictor for the described applications. Notably, it offers the advantage of easy calculability through a simple equation: VA loss = DEQ abs ⋅ 0.23. In 95% of cases, this predicted loss would have an accuracy of ±0.03 lines.

Influence of Lens Thickness on Accuracy of Kane, Hill-RBF 3.0, Barrett Universal II, Emmetropia Verifying Optical, and Pearl-DGS Formulas in Eyes with Nonhigh Myopia and High Myopia

PURPOSE

To investigate the influence of lens thickness (LT) on accuracy of Kane, Hill-RBF 3.0 Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO), and Pearl-DGS formulas in eyes with different axial lengths (AL).

METHODS

The prospective cohort study was conducted at Eye and ENT Hospital of Fudan University. Patients who had uneventful cataract surgery between March 2021 and July 2023 were recruited. Manifest refraction was conducted two-month post-surgery. Eyes were divided into 4 groups based on AL: short (<22mm), medium (22-24.5 mm), medium long (24.5-26mm) and very long (≥26mm). In each AL group, eyes were then divided into 3 subgroups based on the LT measured with IOLmaster700: thin (<4.5 mm), medium (4.5-5.0 mm), and thick (≥ 5 mm). The influence of LT on accuracy of Kane, Hill-RBF 3.0, BUII, EVO, and Pearl-DGS formulas were investigated in each AL group.

RESULTS

A total of 327 eyes from 327 patients were analyzed, with 64, 102, 73 and 88 eyes in each AL group, respectively. In eyes with AL < 24.5 mm, myopic PE was significantly associated with greater LT using all the 5 formulas (all p < 0.05). Backward stepwise multivariate regression analyses revealed that LT was an important influencing factor for PE in all 5 formulas, particularly in eyes with AL <24.5 mm. In eyes with AL <24.5 mm and LT > 5.0 mm, PE of all 5 formulas calculated with the optional parameter LT were more myopic than those calculated without LT.

CONCLUSIONS

Thicker LT was associated with more myopic PE among eyes with AL <24.5 mm when using all 5 formulas. Further optimization of current formulas is necessary, especially for eyes with short AL and thick LT.

Systematic review and meta-analysis of the prevalence of myopia among school-age children in the Eastern Mediterranean Region

Background

The recent increase in myopia is a major public health concern worldwide, including in the Eastern Mediterranean Region (EMR).

Aim

To provide data on the prevalence of myopia among school-age children in the EMR.

Methods

This study was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol. We searched the Web of Sciences, Scopus, Index Medicus for the Eastern Mediterranean Region, ProQuest, PubMed, and Medline for studies on the prevalence of myopia in the EMR published from January 2000 to May 2022. The data were analysed using MedCalc version 19.6.1 and myopia was defined as refractive error ≥ 0.50 D. The overall pooled prevalence of myopia was estimated using a random-effects model and its associated 95% confidence intervals.

Results

The meta-analysis included 27 quality-assessed studies from 13 countries among 51 111 school-age children. The overall pooled prevalence of childhood myopia from 2000 to 2022 was 5.23%, which was significantly higher among females than males (4.90% vs 3.94%). The prevalence of myopia was significantly higher among children aged 11-17 years than among those aged 5-10 years (7.50% vs 3.90%). There was a higher prevalence of myopia with cycloplegic refraction than noncycloplegic refraction (5.95% vs 3.73%). There was highly significant heterogeneity between the studies.

Conclusion

Prevalence of myopia among school-age children in the EMR was high, particularly among older children, and it was more common among females. Early intervention to slow myopia progression is essential in the EMR to protect children from irreversible vision loss.

Pharmacologically Induced Accommodation Palsy and the Bioelectrical Activity of the Muscular System: A Preliminary Investigation

The aim of this study was to pharmacologically induce accommodative paralysis and evaluate its effects on the bioelectrical activity of the muscular system. The study included two participant groups: those with myopia and those with normal vision (emmetropes). Electromyographic assessments were performed using the Noraxon Ultium DTS 8-K MR 3 myo Muscle Master Edition system. The muscles analyzed in this study were the temporalis, masseter, sternocleidomastoid, trapezius, abdominal muscles, biceps brachii, and the external oblique muscles of the abdomen. It is important to acknowledge that, based on the current findings, it cannot be definitively stated that the observed effects have clinical significance, and additional studies are encouraged.

Refractive Changes After Horizontal Strabismus Surgery

PURPOSE

To investigate the changes in refractive status after surgery in patients with horizontal strabismus and high refractive error.

METHODS

This was a prospective study of patients with horizontal strabismus and high refractive error. The patients were divided into a horizontal rectus recession group (group 1) and a horizontal rectus recession combined with horizontal rectus resection group (group 2). The postoperative follow-up duration was 3 months. The refractive status of the patients was evaluated at each postoperative examination, and the refractive changes in the two groups were compared.

RESULTS

The spherical equivalent in group 1 changed by -0.26 D at 3 months postoperatively relative to the preoperative value (p = 0.078), indicating gradual progression toward myopia over time, but the difference was not significant; however, the postoperative cylinder in group 1 significantly increased by 0.34 D at 3 months postoperatively relative to the preoperative value (p = 0.03). The spherical equivalent in group 2 also indicated progression toward myopia; compared with the preoperative value, the spherical equivalent significantly decreased by -0.28 D (p = 0.019) at 1 month postoperatively and decreased by -0.21 D at 3 months postoperatively. The regression line drawn among the points also indicated a progression in the spherical equivalent toward myopia. In group 2, the cylinder increased by 0.30 D (p = 0.004) from the preoperative level at 1 month postoperatively, peaked, then decreased by 3 months postoperatively.

CONCLUSIONS

Patients with high refractive error who undergo horizontal strabismus correction will experience myopic shift. Patients who undergo rectus recession surgery should be fully informed of the possibility of changes in astigmatism preoperatively. For patients who undergo horizontal rectus recession combined with horizontal rectus resection, it is not recommended that glasses be changed within 1 month after surgery.

Detection of significant vision conditions in children using QuickSee wavefront autorefractor

PURPOSE

This study evaluated the ability of QuickSee to detect children at risk for significant vision conditions (significant refractive error [RE], amblyopia and strabismus).

METHODS

Non-cycloplegic refraction (using QuickSee without and with +2 dioptre (D) fogging lenses) and unaided binocular near visual acuity (VA) were measured in 4- to 12-year-old children. Eye examination findings (VA, cover testing and cycloplegic retinoscopy) were used to determine the presence of vision conditions. QuickSee performance was summarised by area under the receiver operating characteristic curve (AUC), sensitivity and specificity for various levels of RE. QuickSee referral criteria for each vision condition were chosen to maximise sensitivity at a specificity of approximately 85%-90%. Sensitivity and specificity to detect vision conditions were calculated using multiple criteria. Logistic regression was used to evaluate the benefit of adding near VA (6/12 or worse) for detecting hyperopia. A paired t-test compared QuickSee without and with fogging lenses.

RESULTS

The mean age was 8.2 (±2.5) years (n = 174). RE ranged up to 9.25 D myopia, 8 D hyperopia, 5.25 D astigmatism and 3.5 D anisometropia. The testability of the QuickSee was 94.3%. AUC was ≥0.92 (excellent) for each level of RE. For the detection of any RE, sensitivity and specificity were 84.2% and 87.3%, respectively, using modified Orinda criteria and 94.5% and 78.2%, respectively, using the American Academy for Pediatric Ophthalmology and Strabismus (AAPOS) guidelines. For the detection of any significant vision condition, the sensitivity and specificity of QuickSee were 81.1% and 87.9%, respectively, using modified Orinda criteria and 93% and 78.6%, respectively, using AAPOS criteria. There was no significant benefit of adding near VA to QuickSee for the detection of hyperopia ≥+2.00 (p = 0.34). There was no significant difference between QuickSee measurements of hyperopic refractive error with and without fogging lenses (difference = -0.09 D; p = 0.51).

CONCLUSIONS

QuickSee had high discriminatory power for detecting children with hyperopia, myopia, astigmatism, anisometropia, any significant refractive error or any significant vision condition.

Ophthalmological conditions among elderly patients attending a private eye care facility in Malawi: A retrospective study

Background

The elderly comprises the fastest-expanding age group globally, with the greatest increase occurring in developing countries. The elderly populace is prone to develop various ocular morbidities.

Purpose

To determine the distribution of ocular morbidities among the elderly population visiting a private eye care facility in Malawi.

Methods

This was a retrospective cross-sectional study conducted at St. John's Hospital in Mzuzu, Malawi. We retrieved data from the hospital's ophthalmic outpatient registry from January, 2021 to December, 2021. A nonprobability census sampling technique was used to retrieve 52 elderly patients. Data analysis were done employing SPSS (v.26).

Results

This study found according to gender a larger proportion were females 27 (51.9%) compared males, who accounted for 25 (48.1%). Refractive error 21 (40.4%) was the most prevalent ocular morbidity followed by cataract 13 (25.0%), pinguecula 6 (11.5%), and glaucoma 4 (7.7%). Although clear differences exist in the distribution of ocular morbidities according to sex (p = 0.529) and age (p = 0.328), the differences are not statistically significant.

Conclusion

The pattern of eye diseases is typical to the country. More resources should be targeting main causes of preventable blindness including refractive error and cataracts at the facility.

Retinal Changes From Hyperopia to Myopia: Not All Diopters Are Created Equal

Purpose

To quantitatively characterize retinal changes across different quantiles of refractive error in 34,414 normal eyes of 23,064 healthy adults in the UK Biobank.

Methods

Twelve optic disc (OD), foveal and vascular parameters were derived from color fundus photographs, correcting for ocular magnification as appropriate. Quantile regression was used to test the independent associations between these parameters and spherical equivalent refraction (SER) across 34 refractive quantiles (high hyperopia to high myopia)-controlling for age, sex and corneal radius.

Results

More negative SER was nonlinearly associated with greater Euclidian (largely horizontal) OD-fovea distance, larger OD, less circular OD, more obliquely orientated OD (superior pole tilted towards the fovea), brighter fovea, lower vascular complexity, less tortuous vessels, more concave (straightened out towards the fovea) papillomacular arterial/venous arcade and wider central retinal arterioles/venules. In myopia, these parameters varied more strongly with SER as myopia increased. For example, while every standard deviation (SD) decrease in vascular complexity was associated with 0.63 D (right eye: 95% confidence interval [CI], 0.58-0.68) to 0.68 D (left eye: 95% CI, 0.63-0.73) higher myopia in the quantile corresponding to -0.60 D, it was associated with 1.61 D (right eye: 95% CI, 1.40-1.82) to 1.70 D (left eye: 95% CI, 1.56-1.84) higher myopia in the most myopic quantile. OD-fovea angle (degree of vertical separation between OD and fovea) was found to vary linearly with SER, but the magnitude was of little practical importance (less than 0.10 D variation per SD change in angle in almost all refractive quantiles) compared with the changes in OD-fovea distance.

Conclusions

Several interrelated retinal changes indicative of an increasing (nonconstant) rate of mechanical stretching are evident at the posterior pole as myopia increases. These changes also suggest that the posterior pole stretches predominantly in the temporal horizontal direction.

Association between maternal fasting glucose levels throughout pregnancy and preschoolers' refractive errors

PURPOSE

We aimed to investigate the association between maternal fasting plasma glucose (FPG) trajectories during pregnancy and children's refractive errors at 6 years old.

DESIGN

Based on the Ma'anshan Birth Cohort (MABC) in China, a total of 1987 mother-child pairs were included in this study.

METHODS

Using the group-based trajectory model, trajectory fitting was performed on fasting blood glucose levels during the first, second, and third trimesters of pregnancy. Children's vision was measured at 6 years of age using the standard logarithmic visual acuity E-chart and cycloplegic refraction examination. Logistic regression models and multi-informant generalized estimating equations were used to analyze the association between maternal blood glucose level and 6-year-old children's visual acuity.

RESULTS

Children born of mothers with high level FPG trajectory had a higher risk of developing refractive error [OR=1.46 (95% CI 1.08 1.97)], hypermetropia [OR=1.64 (95% CI 1.09, 2.46)] and astigmatism [OR=1.60 (95% CI 1.06, 2.41)] at age six compared to those with low level trajectory. Maternal blood glucose level in the first [β=-0.012 (95% CI -0.024, -0.001)] and the second [β=-0.016 (95% CI -0.025, -0.006)] trimesters was associated with 6 year children's distance vision value.

CONCLUSIONS

High level of fasting plasma glucose trajectories during pregnancy has been observed to be associated with 6-year-old children's refractive error, hypermetropia and astigmatism. The first and the second trimesters may be critical periods for the effects of maternal blood glucose on children's vision. The long-term effect of maternal glucose metabolism on children's visual development deserves further study.

Osmosis as nature's method for establishing optical alignment

For eyes to maintain optimal focus, precise coordination is required between lens optics and retina position, a mechanism that in vertebrates is governed by genetics, visual feedback, and possibly intraocular pressure (IOP).1 While the underlying processes have been intensely studied in vertebrates, they remain elusive in arthropods, though visual feedback may be unimportant.2 How do arthropod eyes remain functional while undergoing substantial growth? Here, we test whether a common physiological process, osmoregulation,3 could regulate growth in the sophisticated camera-type eyes of the predatory larvae of Thermonectus marmoratus diving beetles. Upon molting, their eye tubes elongate in less than an hour, and osmotic pressure measurements reveal that this growth is preceded by a transient increase in hemolymph osmotic pressure. Histological evaluation of support cells that determine the lens-to-retina spacing reveals swelling rather than the addition of new cells. In addition, as expected, treating larvae with hyperosmotic media post-molt leads to far-sighted (hyperopic) eyes due to a failure of proper lengthening of the eye tube and results in impaired hunting success. This study suggests that osmoregulation could be of ubiquitous importance for properly focused eyes.

Using Smartphones to Enhance Vision Screening in Rural Areas: Pilot Study

BACKGROUND

While it is treatable, uncorrected refractive error is the number one cause of visual impairment worldwide. This eye condition alone, or together with ocular misalignment, can also cause amblyopia, which is also treatable if detected early but still occurs in about 4% of the population. Mass vision screening is the first and most critical step to address these issues, but due to limited resources, vision screening in many rural areas remains a major challenge.

OBJECTIVE

We aimed to pilot-test the feasibility of using smartphone apps to enhance vision screening in areas where access to eye care is limited.

METHODS

A vision screening program was piggybacked on a charity summer camp program in a rural county in Sichuan, China. A total of 73 fourth and fifth graders were tested for visual acuity using a standard eye chart and were then tested for refractive error and heterophoria using 2 smartphone apps (a refraction app and a strabismus app, respectively) by nonprofessional personnel.

RESULTS

A total of 5 of 73 (6.8%, 95% CI 2.3%-15.3%) students were found to have visual acuity worse than 20/20 (logarithm of minimal angle of resolution [logMAR] 0) in at least one eye. Among the 5 students, 3 primarily had refractive error according to the refraction app. The other 2 students had manifest strabismus (one with 72-prism diopter [PD] esotropia and one with 33-PD exotropia) according to the strabismus app. Students without manifest strabismus were also measured for phoria using the strabismus app in cover/uncover mode. The median phoria was 0.0-PD (IQR 2.9-PD esophoria to 2.2-PD exophoria).

CONCLUSIONS

The results from this vision screening study are consistent with findings from other population-based vision screening studies in which conventional tools were used by ophthalmic professionals. The smartphone apps are promising and have the potential to be used in mass vision screenings for identifying risk factors for amblyopia and for myopia control. The smartphone apps may have significant implications for the future of low-cost vision care, particularly in resource-constrained and geographically remote areas.

Determination of Refractive Error Using Direct Ophthalmoscopy in Children

Purpose

Refractive error is a major cause of visual impairment in children and its early detection can prevent ocular morbidity such as amblyopia and strabismus. Brückner test is a comprehensive test which can be easily administered in children using a direct ophthalmoscope. We aimed to determine refractive error in children by analysis of the red reflex using modified Brückner test.

Patients and Methods

This prospective observational study was conducted on 683 undilated eyes of 683 children aged four to 10 years. They were evaluated with a direct ophthalmoscope from one meter in a dimly lit room. The characteristics of the red reflex and crescent obtained were compared with photoscreener refraction value and analyzed.

Results

The presence of superior crescent was associated with hypermetropia (Chi square 37.11, p < 0.001, kappa = 0.15) and inferior crescent with myopia (Chi square 157.29, p < 0.001, kappa = 0.477). Superior crescent was 98.4% sensitive in detecting hypermetropia. Hypermetropia greater than +1.5D, was associated with larger superior crescent crossing horizontal midline of pupil (Chi square = 5.29, p = 0.021).

Conclusion

The modified Brückner test is useful in detection and quantification of refractive error in children. It is easy, simple, quick and can be employed in the community as a screening test to detect potentially amblyogenic refractive errors.

Prevalence of Refractive Errors Among School-Going Children in Urban Versus Rural Areas

BACKGROUND

The most common cause of visual impairment globally is refractive error. The prevalence of refractive error has been on the rise since the coronavirus disease 2019 (COVID-19) pandemic, possibly due to increased indoor activities and excessive use of electronic devices. Impaired vision during childhood can affect the overall development of a child adversely, and it often remains unreported due to the inability of children to complain about impaired vision.

AIM

The main aim of this study was to assess the prevalence of refractive errors among school-going children in urban and rural areas.

METHODS

This was a cross-sectional study that included 2024 children going to schools situated in urban and rural areas. All study subjects were tested for visual acuity for distance using Snellen's chart with and without glasses after taking a brief history regarding visual complaints. All children who had visual acuity less than 6/6 on Snellen's chart underwent refraction check-ups. Retinoscopy was performed in all study subjects. Analysis of the collected data was done using SPSS for Windows, Version 16.0 (Released 2007; SPSS Inc., Chicago, United States). The analysis of numerical data was done by an unpaired t-test, and the analysis of categorical data was done by a chi-square test. A P-value of less than 0.05 was considered statistically significant.

RESULTS

The mean age of the children was 10.92 ± 2.73 years, with 10.93 ± 2.73 years in urban and 10.91 ± 2.73 years in rural groups. Females (n=1031; 50.93%) were more in number than males (n=993; 49.06%). The overall prevalence of refractive error was 17.43%. The prevalence was higher in urban areas (22.14%) than in rural areas (12.71%). The age group below 10 years comprised 886 (43.77%) study subjects, and 218 (62.1%) children with refractive error had no ocular complaints. The most common refractive error found in this study was simple myopia in both groups, and the least common was astigmatism. The prevalence of uncorrected refractive error was higher in urban school-going children as compared to rural children.

CONCLUSION

The prevalence of refractive error was 17.43% in our study. The prevalence was high in urban areas (22.67%) as compared to rural areas (13.12%). Regular screening of school-going children for refractive errors should be done. Also, awareness regarding the use of electronic gadgets must be raised, especially among urban children.

Role of Machine Learning and Artificial Intelligence in the Diagnosis and Treatment of Refractive Errors for Enhanced Eye Care: A Systematic Review

A significant contributor to blindness and visual impairment globally is uncorrected refractive error. To plan effective interventions, eye care professionals must promptly identify people at a high risk of acquiring myopia, and monitor disease progress. Artificial intelligence (AI) and machine learning (ML) have enormous potential to improve diagnosis and treatment. This systematic review explores the current state of ML and AI applications in the diagnoses and treatment of refractory errors in optometry. A systematic review and meta-analysis of studies evaluating the diagnostic performance of AI-based tools in PubMed was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. To find relevant studies on the use of ML or AI in the diagnosis or treatment of refractive errors in optometry, a thorough search was conducted in various electronic databases such as PubMed, Google Scholar, and Web of Science. The search was limited to studies published between January 2015 and December 2022. The search terms used were "refractive errors," "myopia," "optometry," "machine learning," "ophthalmology," and "artificial intelligence." A total of nine studies met the inclusion criteria and were included in the final analysis. ML is increasingly being utilized for automating clinical data processing as AI technology progresses, making the formerly labor-intensive work possible. AI models that primarily use a neural network demonstrated exceptional efficiency and performance in the analysis of vast medical data, rivaling board-certified, healthcare professionals. Several studies showed that ML models could support diagnosis and clinical decision-making. Moreover, an ML algorithm predicted future refraction values in patients with myopia. AI and ML models have great potential to improve the diagnosis and treatment of refractive errors in optometry.

Prevalence of Comprehensive Eye Examination in Preschool Children With Eye Conditions

Introduction

The purpose of this study is to assess the prevalence of comprehensive eye examinations in multiethnic preschool children, including children with visually significant eye conditions, and identify factors associated with comprehensive eye examinations.

Methods

A sample of 9,197 African American, Hispanic, Asian American, and non-Hispanic White children aged 6-72 months was recruited for the Multi-Ethnic Pediatric Eye Disease Study from 2003 to 2011. Logistic regression performed in 2022 identified independent factors associated with parent-reported history of comprehensive eye examinations. The proportion of children with previous comprehensive eye examinations and the proportion with undetected amblyopia or strabismus were measured.

Results

The prevalence of comprehensive eye examinations was 6.3% overall and 38.3%, 24.8%, 19.1%, 15.1%, and 9.8% among children with strabismus, amblyopia, significant anisometropia, hyperopia, and astigmatism, respectively. Children without prior comprehensive eye examinations were more likely to have undetected amblyopia or strabismus than those with comprehensive eye examination history (ps<0.001). The prevalence of comprehensive eye examinations was higher among older children. Prevalence varied by race/ethnicity, with 8.1%, 7.9%, 6.3%, and 4.9% of non-Hispanic White, Asian American, African American, and Hispanic children having had prior comprehensive eye examinations, respectively; however, the differences did not remain after adjusting for other associated factors. Older age, a primary caregiver with a college/university degree or higher, having vision insurance, gestational age <33 weeks, neurodevelopmental disorder diagnosis, strabismus, and ocular disease history were all statistically significantly associated with a relatively higher prevalence of comprehensive eye examinations in multivariable analyses.

Conclusions

Comprehensive eye examinations were uncommon among preschool children, including those with treatable vision disorders. Interventions, such as parent education and vision insurance, are needed to imaprove comprehensive eye examination access and utilization for at-risk preschool children.

Optic Neuritis in Resolving Phase of COVID-19 Infection and Its Management: A Case Report

Optic neuritis is assumed to be immune-mediated, although the specific antigens that cause demyelination are uncertain. Systemic T-cell activation is detected at the onset of symptoms, which occurs before alterations in cerebrospinal fluid (CSF). The optic nerve disease is a rare disease and can occur in one or both eyes, especially in those with no established inflammatory or autoimmune illnesses. Adult ophthalmic neuritis is usually unilateral and is frequently associated with multiple sclerosis (MS). Generally, it starts as a rapid loss of vision and pain in eye movement. It progresses and achieves the maximal deficiency over a week. The objectives of this paper were to determine the association between coronavirus disease 2019 (COVID-19) and optic neuritis and to study the management of optic neuritis in the resolving phase of COVID-19. A case study was done on a 38-year-old female complaining of sudden diminution of vision in her right eye for one week. She tested positive on the reverse transcriptase-polymerase chain reaction (RT-PCR) test for COVID-19 for which she was managed symptomatically and was started on antiretrovirals. This case report is based on an infrequent COVID-19 complication. It has been proposed that this virus has the probability of manifesting various neurological complications. In our case, optic neuritis occurs mainly three weeks after COVID-19 infection. Our patient was managed by intravenous methylprednisolone injection followed by oral prednisone for 14 days. So, further case studies will be required to support the above treatment plan for optic neuritis caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Unilateral or bilateral optic neuritis can occur as a neurological complication in the resolving stage of COVID-19 infection. Early detection and treatment with steroids can result in the best visual outcome.

Prevalence of Refractive Errors Among Medical Students of Raichur Institute of Medical Sciences, Raichur, Karnataka, India

Introduction Refractive errors (REs) are on the rise among medical students due to the high academic pressure of long hours of reading and their association with close technology. Uncorrected REs cause impaired vision and blindness with considerable morbidity. Documenting the prevalence of REs among medical students helps with early detection and appropriate remedial measures to prevent eye morbidity. Aim The aim of the study was to find the prevalence of REs among medical students at Raichur Institute of Medical Sciences, a medical institution in Raichur City, Karnataka, India. Methodology This hospital-based cross-sectional study was conducted with a total of 425 medical students. An examination of the eye for REs was carried out using a streak retinoscope. The REs were noted in myopia <-0.5 diopters (D), hypermetropia >+0.5 D, and astigmatism >0.5 cylinder D. The data was statistically subjected. Categorical measurements have been presented as frequency (percentage). The chi-square test was applied to the association between the parameters. A p-value less than 0.05 was considered statistically significant. Results Among the 425 observed participants, 160 (37.6%) subjects had REs. Among the REs in the total population, myopia 78 (18.4%) was the most prevalent, followed by hypermetropia and astigmatism, both with 41 (9.6%) and 41 (9.6%) prevalence, respectively. Gender-wise and age-wise, myopia was highly prevalent in both genders and in all age groups except the 20 years age group. Conclusion The prevalence of REs in our study among medical students is a matter of concern, although it is less compared to other previous studies in different geographical areas of India. Regular checkups, early detection, and immediate treatment are very important to prevent further ocular complications.

Association between hyperglycemia during pregnancy and offspring's refractive error: A focused review

This review article explores the relationship between hyperglycemia during pregnancy and the visual development of offspring, specifically focusing on refractive error. The authors conducted a comprehensive search for relevant articles in various databases and assessed the methodological quality of the included studies. The findings consistently indicate that hyperglycemia during pregnancy can have a detrimental impact on the structural and functional aspects of visual development in offspring. The intrauterine hyperglycemic environment appears to negatively affect the retina and lens, leading to refractive errors. In conclusion, there is likely an association between hyperglycemia during pregnancy and the development of refractive errors in offspring.

Quality of Refractive Error Care in Cambodia: An Unannounced Standardized Patient Study

PURPOSE

Quality-of-care in refractive error services is essential, as it directly affects vision outcomes, wellbeing, educational attainment, and workforce participation. In Cambodia, uncorrected refractive error is a leading cause of mild and moderate vision impairment in adults. We evaluated the quality of refractive error care in Cambodia by estimating the proportion of prescribed and dispensed spectacles appropriate for people's refractive error needs and factors associated with spectacle quality.

METHODS

A cross-sectional protocol was employed with 18 Khmer-speaking adult participants observing testing procedures in 156 optical services across six provinces in 2022. A total of 496 dispensed spectacles were assessed against spectacle quality indicators.

RESULTS

The analysis revealed that 35.1% of dispensed spectacles were of optimal quality. The most common error observed in sub-optimal spectacles was the presence of horizontal prism outside of tolerance limits. The study also found that 44.0% of emmetrope visits involved unnecessary prescription spectacle recommendations, and 18.3% of written prescriptions did not correspond with dispensed spectacles. Sex differences were observed, with men predominantly providing refractive error care and women more likely to be unnecessarily recommended prescription spectacles.

CONCLUSION

The findings highlight the importance of prioritizing quality-of-care in refractive error services. A key recommendation is to consider regulatory mechanisms to ensure optical services employ appropriately qualified staff. Additionally, efforts should be made to eliminate unnecessary prescriptions -- especially for emmetropes and females -- standardize written prescriptions, ensure consistent pupil distance measurements, reduce reliance on autorefraction, and address the gender imbalance in the refractive error workforce.

Manhattan Vision Screening and Follow-up Study (NYC-SIGHT): Vision and refractive error results

CLINICAL RELEVANCE

Optometrists can play a key role in providing access to eye care in underserved populations by organising community-based eye health screenings that include optometric exams to detect vision impairment and uncorrected refractive error.

BACKGROUND

Community-based eye health screenings and optometric exams were conducted in the NYC-SIGHT Study.

METHODS

A sub-analysis of vision impairment and refractive error results within a 5-year prospective, cluster-randomised clinical trial. Eligible individuals (age ≥40 years) were recruited from 10 affordable housing developments in Upper Manhattan. Developments were randomised into usual care (received glasses prescription only) and intervention (free glasses) groups. Participants with 6/12 visual acuity or worse, intraocular pressure 23-29 mmHg, or an unreadable fundus image were scheduled with the study optometrist for refraction and a non-dilated exam. Visual improvement data were obtained by comparing the presenting acuity at screening compared to the best corrected acuity after refraction by the optometrist. Chi-square, two-sample t-tests, and a stepwise multivariate logistic regression model were used to determined factors associated with improvable visual impairment.

RESULTS

Seven hundred and eight participants completed screening, 308 received an optometric exam. Those with improvable vision impairment (n = 251), mean age: 69.8 years, 70.5% female, 53% African American, 39.8% Hispanic, >95% had health insurance. Refractive error diagnosed in 87.8% of the participants; lines of improvement: 2 lines (n = 59), 3 to 5 lines (n = 120), and ≥6 lines (n = 72). Stepwise multivariate logistic regression analysis showed that participants with visual acuity 6/12 or worse (odds ratio 16.041, 95% confidence interval 6.009 to 42.822, p = 0.000) or a normal fundus image (odds ratio 2.783, 95% confidence interval 1.001 to 7.740, p = 0.05) had significantly higher odds of improvable vision impairment.

CONCLUSION

This innovative, targeted community-based study included an optometrist who detected high rates of refractive error and improvable vision impairment in an underserved population living in New York City.

Understanding accommodative control in the clinic: Modeling latency and amplitude for uncorrected refractive error, presbyopia and cycloplegia

Accommodation is the process of adjusting the eye's optical power so as to focus at different distances. Uncorrected refractive error and/or functional presbyopia mean that sharp focus may not be achievable for some distances, so observers experience sustained defocus. Here, we identify a problem with current models of accommodative control: They predict excessive internal responses to stimuli outside accommodative range, leading to unrealistic adaptation effects. Specifically, after prolonged exposure to stimuli outside range, current models predict long latencies in the accommodative response to stimuli within range, as well as unrealistic dynamics and amplitudes of accommodative vergence innervation driven by the accommodative neural controller. These behaviors are not observed empirically. To solve this issue, we propose that the input to blur-driven accommodation is not retinal defocus, but correctable defocus. Predictive models of accommodative control already estimate demand from sensed defocus, using a realistic "virtual plant" to estimate accommodation. Correctable defocus can be obtained by restricting this demand to values physically attainable by the eye. If we further postulate that correctable defocus is computed using an idealized virtual plant that retains a young accommodative range, we can explain why accommodative-convergence responses are observed for stimuli that are too near-but not too far-to focus on. We model cycloplegia as a change in gain, and postulate a form of neural myopia to explain the additional relaxation of accommodation often seen with cycloplegia. This model produces plausible predictions for the accommodative response and accommodative convergence signal in a wide range of clinically relevant situations.

Refractive outcome in combined phacovitrectomy: Anterior segment changes and corrective factor for IOL power calculation improvement

PURPOSE

To analyze differences in refractive outcome Δ (difference between postoperative and expected refractive error) and in anterior segment changes between cataract surgery patients and combined phacovitrectomy patients. We also aimed to provide a corrective formula allowing to minimise the refractive outcome Δ in combined surgery patients.

METHODS

Candidates for phacoemulsification and combined phacovitrectomy (respectively PHACO and COMBINED groups) were prospectively enrolled in two specialised centres. Patients underwent best corrected visual acuity (BCVA) assessment, ultra-high speed anterior segment optical coherence tomography (OCT), gonioscopy, retinal OCT, slit lamp examination and biometry at baseline, 6 weeks postoperatively and 3 months postoperatively.

RESULTS

No differences in refractive Δ, refractive error and anterior segment parameters were noted between PHACO and COMBINED group (109 and 110 patients respectively) at 6 weeks. At 3 months, COMBINED group showed a spherical equivalent of -0.29 ± 0.10 D versus -0.03 ± 0.15 D in PHACO group (p = 0.023). COMBINED group showed a significantly higher Crystalline Lens Rise (CLR), angle-to-angle (ATA) and anterior chamber width (ACW) and a significantly lower anterior chamber depth (ACD) and refractive Δ with all 4 considered formulas at 3 months. For IOL power lower than 15, a hyperopic shift was observed instead.

CONCLUSIONS

Anterior segment OCT suggests anterior displacement of the effective lens position in patients undergoing phacovitrectomy. A corrective formula can be applied to IOL power calculation to minimize undesired refractive error.