Refractive outcomes using Barrett formulas and patient characteristics of cataract surgery patients with and without prior LASIK/PRK.

PURPOSE: The goal of this study is to describe characteristics of cataract surgery patients who previously underwent laser in situ keratomileusis/photorefractive keratectomy (LASIK/PRK) in comparison to non-LASIK/PRK cataract surgery patients including psychiatric comorbidities, as well as describe refractive prediction error after cataract surgery while accounting for axial length (AL) using the Barrett True-K and Barrett Universal II formulas. METHODS: This was a retrospective study of patients from the University of Colorado Cataract Outcomes Registry. The primary outcomes were refraction prediction error (RPE), mean absolute RPE, and median absolute RPE. Outcomes were stratified by five axial length groups. Univariate and multivariate models for RPE were stratified by the AL group. RESULTS: Two hundred eighty-one eyes with prior LASIK/PRK and 3101 eyes without are included in the study. Patients with prior LASIK/PRK were significantly younger: 67.0 vs 69.9 years, p < 0.0001. The LASIK/PRK group had significantly better mean pre-operative BCVA in comparison to the non-LASIK group, logMAR 0.204 vs logMAR 0.288, p = 0.003. The LASIK/PRK group had significantly lower rates of cardiovascular disease (18.5% vs 29.3%, p < 0.001), hypertension (49.1% vs 59.3%, p < 0.012), and type 2 diabetes (10.7% vs 26.0%, p < 0.001), and no significant difference in psychiatric disease. The absolute RPE was higher for the LASIK group for all ALs, but only significantly higher for eyes with AL less than 25 mm. CONCLUSION: Patient eyes with prior LASIK/PRK surgery undergoing cataract surgery were significantly younger, had significantly less comorbidities, and a significantly better pre-operative BCVA. Using the Barrett formulas, absolute prediction error for eyes with longer ALs was not significantly worse for LASIK/PRK eyes than those without and the difference was smaller for eyes with longer AL.

The Relationship between Selected Parameters and the Occurrence of Premyopia in a Group of 1155 Children Aged 8 in Northwestern Poland.

Background: Determination of the number of pupils at risk of developing pre-myopia and selected ophthalmic parameters in a group of 1155 children aged 8. Material: Ophthalmic examinations were performed in Polish 8-year-old, /1518 individuals/; 1155 of whom presented complete data for analysis. There was a total of 554 (47.9%) girls and 602 (52.1%) boys. Examination of the anterior and posterior segment of the eye, evaluation of accommodation, convergence, heterophoria, alignment of the eyeball, muscular balance with ocular mobility in 9 directions of gaze, and spatial vision were tested. Refraction was obtained under cycloplegia. Refractions (spherical equivalent, SE). were categorized as pre-myopia (-0.50 D-+0.75 D), myopia (≤-0.5 D), emmetropia (>-0.5 D to ≤+0.5 D), mildly hyperopia (>+0.5 D to ≤+2.0 D) and hyperopia (>+2.0 D). Data analysis was performed using Statistica 13.5 software: chi-squared, Pearson's, t-Student, and U Mann-Whitney tests. p-values of <0.05 were considered statistically significant. Results: Pre-myopia was diagnosed in as many as 704 subjects (60.9%) with a similar frequency among both girls-328 (46.6%)-and boys with 376 (53.4%). Conclusions: Current data indicates that the growing group of myopic individuals in many industrialized countries is the sixth most common cause of blindness. Further research is crucial to understand the factors underlying accommodative and binocular mechanisms for myopia development and progression and to make recommendations for targeted interventions to slow the progression of myopia in a group of early school children.

Clinical profile of amblyopia in a tertiary care facility without proper vision screening in Saudi Arabia.

PURPOSE: To evaluate the clinical profile of amblyopia among patients referred to a tertiary care facility in Saudi Arabia. METHODS: All patients between 1 and 14 years presenting to the amblyopia clinic from 2016 to 2020 were retrospectively reviewed. Amblyopia was defined as visual acuity <0.2 LogMAR (20/30) in the worse eye or two-line difference between the two eyes. We classified patients into strabismic, refractive, mixed strabismic, and refractive and deprivation amblyopia. We subclassified our cohort according to age (< and ≥5 years). RESULTS: Three hundred and eighty-three patients (199 male 54%) were seen in our clinic. Seventeen patients were excluded because they did not meet our inclusion criteria. The mean age at presentation was 5.05 ± 2.49 years. Strabismic amblyopia was found in 180 (49%), refractive in 101 (27.6%), mixed in 69 (19%), and deprivation in 16 (4.2%). Anisometropia in 85.25% and isometropia in 14.75%. Hyperopic astigmatism was the most common refractive error in 246 (67.2%). Esotropia was the most common deviation (90%). Strabismic amblyopia was significantly higher in the <5 years group (62.4% vs. 36.7%). While refractive amblyopia was significantly higher in ≥5 years group (38.8% vs. 15.7%) (P < 0.001). CONCLUSION: Strabismic amblyopia was the most commonly diagnosed in our cohort, especially among patients <5 years of age. Refractive amblyopia was more common in older patients and may be under-detected due to the lack of proper vision screening. The implementation of proper vision screening should help in early detection and successful treatment at an early age.

Assessment of tear film parameters in females with refractive errors using a single device: An observational study.

This observational study aimed to evaluate the use of a single portable device to assess the non-invasive tear break-up time (NITBUT), tear meniscus height (TMH), and lipid layer patterns (LLP) in young females with refractive errors (REs). The study was conducted at the College of Applied Medical Science (Female campus), Riyadh, Saudi Arabia between January 5, 2021 to May 15, 2021. Forty young females, with mean age of 23.0± 4.3 years with REs (-2.53 ± 2.05 D) and 40 females, mean age 23.8± 4.5 years with healthy eyes were recruited. The tests were administered in the following order: Ocular Surface Disease Index (OSDI), followed by NITBUT, TMH, and LLP. Significant differences (via Mann-Whitney U test) were noted in the median ocular surface disease index (OSDI; p˂0.001), NITBUT (p=0.035), TMH (p=0.009), and LLP (p˂0.001) scores between the study and control groups. Females with REs have significantly lower lipid layer, TMH, and NITBUT scores than those with healthy eyes.

Colombian Ocular Diseases Epidemiology Study (CODES): Prevalence and Sociodemographic Characterization of Refractive Errors in Colombian Eye Care Consultations.

PURPOSE: To estimate the prevalence and demographic characteristics of uncorrected refractive errors (URE) in people who attended eye care consultations in Colombia between 2015 and 2019, using the National Health Registry data. METHODS: We identified ICD codes for myopia (H-52.1), degenerative myopia (H-44.2), hyperopia (H-52.0), and astigmatism (H-52.2) from the Integrated Social Protection Information System. Crude prevalence rates by age and sex were calculated for the population attending eye care services during these years. Additionally, we developed a standardized morbidity map across county departments. RESULTS: In Colombia, the prevalence of URE among eye care consultations was 30.26%, increasing from 30.39% in 2015 to 35.14% in 2019. Of the 1,579,778 cases analyzed, 60.9% were females. Astigmatism emerged as the most prevalent URE, predominantly seen in individuals under 40 years old. Myopia showed the highest prevalence in the 10-30 age group, whereas hyperopia was most prevalent in the first decade of life. Geographically, the Andean region recorded most of URE cases, while more remote areas have seen a rising morbidity risk in recent years. CONCLUSIONS: The rising trend of URE in Colombia and its demographic and geographical variations underscores the urgent need for health professionals and government authorities to acknowledge and address this issue. This study provides crucial insights into the refractive error landscape across the country, highlighting the necessity for prevention programs specifically designed to cater to the country's unique needs.

Agreement in non-cycloplegic and cycloplegic refraction between a photoscreener and a calibrated autorefractor.

INTRODUCTION: Photoscreeners have been shown to provide excellent measurements of the refractive error. However, whether they could be used for assessing cycloplegic refraction has not been examied. This study aimed to evaluate the agreement between cycloplegic and non-cycloplegic measurements obtained using a photoscreener and stationary autorefractor, respectively. METHODS: This study included all patients undergoing routine ophthalmic examination at the Hygeia Clinic (Poland) from June to July 2022. Each patient underwent non-cycloplegic and cycloplegic refraction assessments using the 2WIN photoscreener (Adaptica SRL, Padova, Italy) and an ARK-1 stationary autorefractor ARK-1 (Nidek Co Ltd., Tokyo, Japan), respectively. Each pair of assessments was conducted in random order, and all values were determined at a vertical distance of 12 mm. The agreement between cycloplegic and non-cycloplegic measurements was assessed using paired t-tests, Bland-Altman and ABCD ellipsoids. RESULTS: This analysis included 82 patients, of which 52 were female. Their mean age was 34.39 ± 13.13 years. The non-cycloplegic spherical equivalent (SE) did not differ significantly between the 2WIN (- 1.22 ± 2.45) and ARK-1 (- 1.19 ± 2.96) devices (p = 0.580). However, the cycloplegic SE values demonstrated more negative values with the 2WIN device (- 1.13 ± 2.19) than with the ARK-1 device (- 0.75 ± 3.03; p = 0.007). The non-cycloplegic and cycloplegic measurements were strongly correlated between the devices (r = 0.9473 and 0.9411, respectively). However, the correlation between their cycloplegic shifts in SE was low (r = 0.2645). Ellipsoid refraction aligned better non-cycloplegic (ARK-1 = 1.00; 2WIN = 1.74) than with cycloplegic refraction (ARK-1 = 1.43; 2WIN = 1.90). CONCLUSION: While the cycloplegic measurements obtained with the 2WIN photoscreener were strongly correlated with those obtained with the ARK-1 stationary autorefractor for most of the analyzed parameters, they should not be considered interchangeable.

Magnitude and Determinants of Awareness Regarding Refractive Surgeries Among Saudi Adults.

Objectives: This study aimed to present the magnitude and determinants of awareness about refractive surgery among the adult Saudi population and recommend knowledge improvement. Methods: This web-based cross-sectional study was conducted between June 2020 and May 2021 across various regions of Saudi Arabia on the adult Saudi population. A total of 11 close-ended questions regarding indication, contraindication, preparation and surgery procedures were asked. The awareness scores were grouped as 'good' (≥6) or 'poor' (≤5). Demographic and ocular parameters were associated with the outcomes. Results: Of the 6,746 participants, 6,580 (response rate = 97.5%) completed the survey. The participation of younger women and older men was greater than their proportions in the population, while older women participated less than their proportion. Good awareness about refractive surgery was noted in 1,165 (17.7%; 95% confidence interval: 16.2-18.0) participants. Women (P <0.001), the 18-29 age group (P <0.001), residents of the central region of Saudi Arabia (P <0.001), health professionals (P <0.001), health sector students (P = 0.0004), people with myopia (P <0.001) and history of refractive surgery (P <0.001) were associated with good awareness. Women (adjusted odds ratio [AOR] = 1.5; P <0.001), health sector students (AOR = 1.57; P <0.001), and residents in the central region (AOR = 1.27; P <0.001) were independent predictors of awareness. Knowledge about contraindications for surgery was good in more than one-third of the participants. Of the 535 participants who underwent surgery in the past, 452 (84.5%) were satisfied with their outcomes. Conclusion: Awareness of refractive surgeries is low in the adult Saudi population. Targeted counseling is recommended to improve the knowledge and acceptance of refractive surgery.

Refractive Errors Among Members of the Armed Forces of the Czech Republic.

Objective: To evaluate the prevalence of refractive errors among members of the Armed Forces of the Czech Republic, to recommend a safe way of correcting refractive errors with regard to the specific needs of military personnel (especially members of combat units and flying personnel), and to propose a system for solving these errors in order to increase combat effectivity. Methodology: Questionnaire to determine previous refractive surgery and spectacle correction wear. Measurement of refraction with a hand-held autorefractometer and evaluation of current visual acuity on ETDRS optotypes (Landolt rings). Results: 259 servicemen (518 eyes) were investigated. The return rate of the questionnaires was 100%. The incidence of myopia greater than -0.75D was 22% (113 eyes), myopia greater than -0.5D 32% (166 eyes). The mean value of myopia was -0.78 D (SD ±0.6). Hypermetropia values ranged from +0.25 to +5.0 D. The mean value of hypermetropia was 0.63 D (SD ±0.7). Astigmatism values ranged from -0.25 to -3.75. The mean value of astigmatism was -0.55 Dcyl (SD ±0.49). The average visual acuity was 84.1 letters ETDRS SD (±6.1), visual acuity worse than 80 letters was manifested by 23% of the members of the monitored group. 25 people (10%) had undergone laser refractive surgery. Visual acuity after laser refractive surgery was measured in 19 people (38 eyes). Mean uncorrected post-laser visual acuity was 83.87 (SD ±6.1) ETDRS letters. The mean follow-up period after laser refractive surgery was 6.78 (SD ±4.8) years. Conclusion: Despite the initial selection of military personnel and entry limitations, the prevalence of refractive errors is comparable to the general population. However, in contrast with the general population, refractive errors larger than -3.0 D were not represented in the group. Due to the finding of insufficient correction of refractive errors, increased emphasis should be placed on identifying and regularly observing military personnel with refractive errors

Association Between Peripheral Retinal Defocus and Myopia by Multispectral Refraction Topography in Chinese Children.

Objective: To investigate the association between the peripheral refractive errors of the fundus in different regions and moderate and high myopia. Methods: In this case-control study, 320 children and adolescents aged 6 to 18 years were recruited. Peripheral refractive errors were measured using multispectral retinal refractive topography (MRT). Spherical equivalent (SE) and cylinder errors were classified into low, moderate, and high categories based on the magnitude range. Logistic regression was performed to test the factors associated with myopia. Results: There were 152 participants with low myopia and 168 participants with moderate and high myopia included in the current study. Participants with moderate and high myopia were most likely to be older, with larger axial length (AL), lower SE, less time to watch electronic devices on the weekend, a higher difference between central refractive error and paracentral refractive error from the superior side of the retina (RDV-S), but a smaller difference between the central refractive error and paracentral refractive error from the inferior side of the retina (RDV-I) than those with low myopia (all P <0.05). After logistic analysis, female sex (odds ratio [OR] = 4.14; 95% confidence interval [CI] = 2.16-7.97, P <0.001), AL (OR = 6.88, 95% CI = 4.33-10.93, P <0.001), and RDV-I (OR = 0.52, 95% CI = 0.32-0.86, P = 0.010) were independent factors for moderate and high myopia. Conclusion: Our study demonstrated that the retina peripheral refraction of the eyes (RDV-I) was associated with moderate and high myopia, and RDV-S was only associated with high myopia.

Refractive error and vision related quality of life.

BACKGROUND: To investigate and compare the vision-related quality of life (QOL) in different types of refractive error (RE). METHODS: This cross-sectional study was performed on 200 subjects, categorized into four groups of 50 each, consisting of subjects with myopia, hyperopia, astigmatism, and emmetropia, the latter being the control group. The mean age of the participants was 23.88 ± 5.87 (range, 15 to 38: 110 females and 90 males). RE was defined as myopia, spherical equivalent (SE) < -0.25 diopters (D), hyperopia, SE > + 0.25 D, astigmatism, cylinder < -0.25 D, and emmetropia (-0.25 ≤ SE(D) ≤ + 0.25, cylinder ≥ -0.25). Groups are subdivided into very low magnitudes of RE (0.50 and 0.75) and significant RE (1.00 ≤). Vision-related QOL was assessed using the Persian version of the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25). The NEI-VFQ was scored as visual function and socioemotional scales using Rasch analysis. RESULTS: Corrected myopia, astigmatism, uncorrected myopia, and hyperopia had a lower vision-related QOL than emmetropes. (P < 0.001). Vision-related QOL in myopic subjects was lower than that in astigmatic participants. Very low myopes, who often do not use correction, had a significantly lower QOL than other groups. CONCLUSION: Individuals with refractive errors experience a lower QOL score than those without. Notably, the adverse impact on QOL score is significantly greater in myopic cases, particularly very low myopia, compared to other refractive errors. Therefore, it is strongly recommended not to neglect managing very low myopia since it may improve participants' QOL.

Causal associations of refractive error and early age-related macular degeneration: A Mendelian randomization study.

This study aims to determine the risk associated with early age-related macular degeneration (AMD) due to refractive errors (RE) using an analysis of genome-wide association study (GWAS) data through the two-sample Mendelian randomization approach. Single-nucleotide polymorphisms (SNPs) linked to refractive errors (RE) were obtained from numerous GWAS studies involving individuals of European descent. The data for early AMD was obtained from a diverse, multiethnic GWAS meta-analysis that included 105,248 participants (14,034 cases and 91,214 controls). The primary outcome measure focused on the rise in early AMD risk corresponding to a 1-diopter alteration in spherical power and cylindrical power. In the main Mendelian randomization analysis, inverse-variance weighting (IVW) methods were applied for the evaluation. Mendelian Randomization (MR) study revealed a substantial impact of refractive error (RE) on early AMD risk, with a 1-diopter increase in hypermetropia being related to a 1.16 odds ratio (OR) for a greater risk of early AMD (95% CI, 1.10-1.23; P < 0.01). This conclusion was further supported by four supplementary approaches, namely, Weighted mode, Weighted-median, Simple mode, and MR-Egger. The results suggest a heightened risk of early AMD correlated with hyperopia, necessitating further research to thoroughly elucidate this potential causal relationship.

[Global ophthalmology : Update]. / Globale Ophthalmologie : Aktueller Stand.

The aim of global ophthalmology is to maximize vision, ocular health and functional ability, thereby contributing to overall health and well-being, social inclusion and quality of life of every individual worldwide. Currently, an estimated 1.1 billion people live with visual impairment, 90% of which can be prevented or cured through largely cost-effective interventions. At the same time, 90% of people affected live in regions with insufficient eye health coverage. This challenge drove the World Health Organization (WHO) and a group of nongovernmental organizations to launch "VISION 2020: the Right to Sight", a global campaign which recently concluded after 20 years. The achievements, challenges and lessons learned were identified and incorporated into the current campaign "2030 IN SIGHT".

Non-compliance of Spectacle Wear in School-Going Children With Refractive Errors.

Background Uncorrected refractive errors are the most common cause of avoidable visual impairment in children worldwide. The school screening of refractive errors is one of the most important initiatives outlined in WHO Vision 2020 targets for control of avoidable visual impairment in children. However, the benefit depends on the compliance of the spectacle worn by children. Objective To determine non-compliance of spectacle wear and its predisposing factors among school-going children in Lahore, Pakistan. Methods This cross-sectional analytical study was conducted among 200 school-going children (5-16 years), with spectacle prescription for at least the last six months studying in primary and secondary schools of Lahore, by using convenience sampling. We collected data with the help of a standardized, self-administered, close-ended questionnaire determining age, gender, class, and non-compliance and its reasons. Data were subjected to statistical evaluation using Statistical Product and Service Solutions (SPSS, version 26; IBM SPSS Statistics for Windows, Armonk, NY), and a chi-square test was applied to determine the statistical significance. p-value 0.05 was considered significant. Results Of the 200 children, 42 were boys, and 158 were girls, with a mean age of 12 years with a standard deviation of 2.6. The proportion of spectacle wear non-compliance was 19.5% (n=39). Children with non-compliance were more likely in the age group of 14-16 years (n=20{51.3%}; p=0.039). The main reasons for non-compliance were dislike to wear spectacles (28.2%), broken spectacles (23.1%), spectacles causing headache (20.5%), spectacles lost and parents' disapproval (20.5%), and peer pressure/teasing (15.4%). Significant difficulties faced while wearing spectacles were pressure on the nose due to worn-out nose pads (36.4%), pressure on ears causing pain in the temple and headache (34.1%), repeated cleaning of spectacles (29.5%), heavy spectacles (18.2%), excessive glare and pain in the eyes (12.5%), and improper fitting of spectacles (11.4%). Conclusions We found that non-compliance was more significant in school-going children aged 14-16 years and girls. The main reasons were unlikeness to wear, broken spectacles, headache, and spectacles lost. School children were not compliant because of many issues that should be addressed, and this information will be used for better eye care in school-going children with refractive errors.

Idiopathic scoliosis in subjects with eye diseases: A systematic review with meta-analysis.

Our aim was to find the best evidence on the prevalence of idiopathic scoliosis (IS) in subjects with eye diseases (EDs) and to determine the most common visual alterations that are present. Following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), a bibliographic search up to June 2023 in the PubMed, PsycINFO, SCOPUS, and CINAHL Complete databases was performed. Observational studies were selected and the results were analyzed with prevalence odds ratio (OR). A total of six studies, including 18,396 subjects, were selected. The group of subjects with EDs was made up of 6048 individuals, of whom 655 (10.83%) had IS. The group of subjects without EDs was made up of 12,348 individuals of whom 444 (3.60%) presented with IS with an OR = 2.91, CI (95%) = [1.75, 4.83]. Blindness was assessed in a single study with an OR = 7.83, CI (95%) = [1.66, 36.90]; all three studies in the refractive error subgroup yielded an OR = 2.24, CI (95%) = [1.10, 4.58]; and the two studies that included subjects with strabismus showed an OR = 3.09, CI (95%) = [1.38, 7.00]. EDs were associated with an almost three times greater odds of having IS. We recommend the inclusion of vision testing in children with IS.

Exploring Correlations between Headaches and Refractive Errors in an Optometry Clinic Sample.

Background & Aim: The optometrist is often one of the professionals patients consult when they have headaches. The limitations inherent in previous studies on the topic limit the utilization of their findings. Therefore, the aim of conducting the present study was to explore correlations between headache and refractive errors in a clinical setting using extended classification criteria. Methods: The study design was cross-sectional, and sample comprised (headache group = 1062; non-headache group = 1095) participants aged 10-40 years who attended an optometry practice. During case-history taking, participants were classified as headache and non-headache group. Refraction, ocular health examinations, accommodative and vergence tests were performed. Headaches were sub-classified according to the anatomic location such as temporal, frontal, occipital, or diffuse, based on where pain was felt. Results: Temporal and temporo-frontal headaches were most frequent. Participants in the headache group numbered 1062 with mean age 25.1 ± 8.6; females 841 (79.1%) and males 221 (20.8%) while those in the no headache group numbered 1095 with mean age 25.3 ± 8.7; females 648 (59.1%). Low amount spheres and cylinders (p = 0.003) as well as hyperopic, and against-the-rule astigmatism (p = 0.012) and (p = 0.03) respectively were significantly more frequent in the headache group. Conclusion: Temporal headaches were most frequent. Patients with low spheres and cylindrical errors as well as hyperopic and against-the-rule astigmatism were significantly more prone to headaches. This study provides findings, which have not been reported. Findings have implications for clinical practice and highlights the need to compensate for low ametropia. A standard study protocol is recommended.

Deep Transfer Learning for Ethnically Distinct Populations: Prediction of Refractive Error Using Optical Coherence Tomography.

INTRODUCTION: The mismatch between training and testing data distribution causes significant degradation in the deep learning model performance in multi-ethnic scenarios. To reduce the performance differences between ethnic groups and image domains, we built a deep transfer learning model with adaptation training to predict uncorrected refractive errors using posterior segment optical coherence tomography (OCT) images of the macula and optic nerve. METHODS: Observational, cross-sectional, multicenter study design. We pre-trained a deep learning model on OCT images from the B&VIIT Eye Center (Seoul, South Korea) (N = 2602 eyes of 1301 patients). OCT images from Poona Eye Care (Pune, India) were chronologically sorted into adaptation training data (N = 60 eyes of 30 patients) for transfer learning and test data (N = 142 eyes of 71 patients) for validation. Deep learning models were trained to predict spherical equivalent (SE) and mean keratometry (K) values via transfer learning for domain adaptation. RESULTS: Both adaptation models for SE and K were significantly better than those without adaptation (P < 0.001). In myopia/hyperopia classification, the model trained on circular optic disc OCT images yielded the best performance (accuracy = 74.7%). It also performed best in estimating SE with the lowest mean absolute error (MAE) of 1.58 D. For classifying the degree of corneal curvature, the optic nerve vertical algorithm performed best (accuracy = 65.7%). The optic nerve horizontal model achieved the lowest MAE (1.85 D) when predicting the K value. Saliency maps frequently highlighted the retinal nerve fiber layers. CONCLUSIONS: Adaptation training via transfer learning is an effective technique for estimating refractive errors and K values using macular and optic nerve OCT images from ethnically heterogeneous populations. Further studies with larger sample sizes and various data sources are needed to confirm the feasibility of the proposed algorithm.

Long-Term Visual Outcomes in Prematurely Born Children.

PURPOSE: Prematurely born children are at risk of numerous complications that affect the visual system. Retinopathy of prematurity (ROP) and cerebral visual impairment (CVI) are among two major causes of childhood blindness and visual impairment in industrialized nations, and large countries with emerging economies are seeing increasing childhood blindness from ROP alone, adding to the burden of disease worldwide. The purpose of this paper is to review the long-term impacts of prematurity, ROP and CVI on vision in children who were born preterm. METHOD: The topics in this review of the literature include the burden of vision loss in prematurely born children world-wide, a description of ROP and CVI, effects on visual acuity, refractive errors, strabismus and binocularity, visual fields and contrast sensitivity, and risk factors for visual complications. RESULTS: Children who are most at risk of visual complications are those with the smallest gestational age at birth and birth weight in general. Although ROP severity and the presence of neurological impairments including CVI play a large role in the development of poor visual outcomes, premature birth alone without CVI or severe ROP increases the risk of future visual complications. Awareness of signs and symptoms of CVI are important in the management of affected children. CONCLUSION: Children born preterm are at increased risk of reduced visual acuity, refractive errors, strabismus and amblyopia, complications of ROP, CVI, visual field abnormalities and reduced contrast sensitivity. Awareness of risk factors warranting close monitoring and signs and symptoms of CVI are critical to optimize the visual outcomes and overall development.

Prevalence of refractive errors in population aged 50 years and over: The Gilan eye study.

PURPOSE: To describe the prevalence of refractive error (RE) and its association with other environmental and health factors among population aged ≥50 years who lived in Gilan, Iran in 2014. METHODS: In this population-based cross-sectional study, 3281 individuals aged ≥50 years living in Gilan for at least 6 months were enrolled. The prevalence of different types of REs including myopia (spherical equivalent (SE)≤-0.50D), high myopia (SE ≤ -6.00D), hyperopia (SE≥ + 0.50D), high hyperopia (SE≥ + 3.00D), astigmatism (cylinder < -0.50D) and high astigmatism (cylinder < -2.25D) were determined. Anisometropia was defined as the SE difference of ≥1.00D between the two eyes. Associated factors including age, body mass index (BMI) and education were also studied. RESULTS: 2587 eligible individuals (58% female subjects) with the mean age of 62.6 ± 8.8 years participated (87.6% response rate). The prevalence of myopia, hyperopia and astigmatism was 19.2%, 48.6% and 57.4%, respectively. 3.6% high hyperopia, 0.5% high myopia and 4.5% high astigmatism were identified. The positive simultaneous effects3 of older age (Odds Ratio (OR) = 3.14), nuclear (OR = 1.71) and posterior subcapsular (OR = 1.61) cataracts as well as the negative effects of higher levels of education (OR = 0.28) were obtained on myopia. Higher BMI was found as a risk factor for hyperopia (OR = 1.67), while older patients were less likely to be hyperopic (OR = 0.31). CONCLUSION: Higher incidence of myopia and astigmatism was found in patients aged over 70 years. It was also found that patients at older ages who suffered with cataracts were at a higher risk of myopia, while elderly people with greater BMI were at a higher risk of hyperopia.

Ametropia detection using a novel, compact wavefront autorefractor.

INTRODUCTION: Despite the well-known reproducibility issues of subjective refraction, most studies evaluating autorefractors compared differences between the device and subjective refraction. This work evaluated the performance of a novel handheld Hartmann-Shack-based autorefractor using an alternative protocol, which considered the inherent variability of subjective refraction. METHODS: Participants underwent an initial measurement with a desktop autorefractor, two subjective refractions (SR1 and SR2) and a final measurement with the QuickSee Free (QSFree) portable autorefractor. Autorefractor performance was evaluated by comparing the differences between the QSFree and each of the subjective refractions with the difference between the subjective refractions (SR1 vs. SR2) using Bland-Altman analysis and percentage of agreement. RESULTS: A total of 75 subjects (53 ± 14 years) were enrolled in the study. The average difference in the absolute spherical equivalent (M) between the QSFree and the SR1 and SR2 was ±0.24 and ±0.02 D, respectively, that is, very similar or smaller than the SR1 versus SR2 difference (±0.26 D). Average differences in astigmatic components were found to be negligible. The results demonstrate that differences between QSFree and both subjective refractions in J0 and J45 were within ±0.50 D for at least 96% of the measurements. The limits of agreement (LOAs) of the differences between QSFree and SR1, as well as QSFree and SR2, were higher than those observed between SR1 and SR2 for M, J0 and J45 . CONCLUSIONS: A protocol was designed and validated for the evaluation of a refractive device to account for the variability of subjective refraction. This protocol was used to evaluate a novel portable autorefractor and observed a smaller difference between the device and subjective refractions than the difference between the two subjective refraction measurements in terms of mean bias error, although the standard deviation was higher.

A comparative analysis of the influence of refractive error on image acuity using three eye models.

PURPOSE: To analyse and compare image acuity for different refractive errors generated by either altering axial length or corneal curvature and using three human eye models with two pupil sizes. METHODS: Three different eye models, Liou-Brennan, Goncharov and Navarro, were used. Simulations were made (using Ansys Zemax OpticStudio 22.3) for real pupil sizes of 3 and 6 mm with refractive errors ranging from -2 to +2 D in 0.25 D increments. Refractive errors were simulated by varying axial length or corneal curvature. Root mean square (RMS) values were used to determine image acuity. RESULTS: For the 3-mm pupil, all models gave similar results, with the Navarro model having slightly higher RMS values for the emmetropic eye. For the 6-mm pupil, the Liou-Brennan and Goncharov eye models gave similar results, with RMS values lower than for the Navarro eye model. The highest RMS value was visible in the axial length-induced refractive errors. Refractive errors generated by altering corneal curvature give smaller RMS values than those generated by altering axial length. The axial length and corneal radius simulations indicate a wide spread of results for myopic, hyperopic and emmetropic eyes. There are multiple outcomes that give the same refractive error, even within a single-eye model. The axial length/corneal curvature ratio showed a higher ratio for myopes than hyperopes for every model. CONCLUSIONS: The influence of refractive error on image acuity varied depending on the simulation method of refractive error and the model used. The origins of refractive error and the influence it has on image acuity need further investigation. As models become more sophisticated, personalised and biologically relevant, they will better represent the image acuity of the eye for varying refractive errors, ethnicities, ages and pupil sizes.