Difference In Refractive Error Research Articles

A voxel-based magnetic resonance study of cortical gray matter structures in intermittent exotropia

Objective: To explore the changes in gray matter volume of the cerebral cortex in patients with intermittent exotropia (IXT) using the voxel-based analysis and to analyze the correlation between these changes and clinical manifestations. Methods: This was a cross-sectional study. A collection of 15 consecutive patients diagnosed with IXT at Tianjin Eye Hospital from March 2021 to May 2022 formed the exotropia group, which comprised 8 males and 7 females, with an average age of (23.5±5.2) years. Ten healthy individuals, 3 males and 7 females, with an average age of (27.0±7.5) years, were selected as the control group. All participants underwent assessments of exotropia severity and Titmus stereoacuity. Three-dimensional high-resolution brain images were obtained through MRI scans. Voxel-based morphometry was employed to preprocess the MRI data, and the SPM toolbox in MATLAB was utilized to analyze differences of images between the two groups. Regions of interest (ROI) with structural abnormalities in the gray matter volume analysis were selected, and the ratio of gray matter voxel values in the ROI to the mean gray matter voxel values of the whole brain for each participant was calculated using the MarsBaR software. The correlation between this ratio and exotropia severity as well as the common logarithm of Titmus stereoacuity was analyzed. Results: The differences in age, gender distribution, and refractive error between the two groups were not statistically significant (all P>0.05). However, there were statistically significant differences in the degree of strabismus and Titmus stereoacuity (both P<0.001). Compared to the control group, patients in the strabismus group exhibited decreased gray matter volume in several brain regions, including the wedges of the medial surface of the cerebral hemisphere (decreased by 89 voxels), the left lingual gyrus (decreased by 176 voxels), the left calcarine sulcus V3 area (decreased by 30 voxels), the central anterior gyrus of the right frontal lobe (decreased by 192 voxels), the gray matter of the left hippocampal gyrus (decreased by 20 voxels), and the bilateral lateral geniculate nuclei (decreased by 100 and 40 voxels on the left and right sides, respectively). These differences were all statistically significant (all P<0.001). Additionally, there was an increase in gray matter volume in several brain regions, including the bilateral caudate nuclei (increased by 60 and 76 voxels on the left and right sides, respectively) and the left precentral gyrus (increased by 36 voxels). These differences were also statistically significant (all P<0.001). A group-level analysis identified 10 brain regions with structural differences between the two groups, which were used as ROI. The gray matter volume ratio was negatively correlated with the degree of exotropia (all P<0.05) in the ROI of the left wedges (r=-0.670), left calcarine sulcus V3 area (r=-0.610), and left lingual gyrus (r=-0.684). The gray matter volume ratio was negatively correlated with lgTS (all P<0.05) in the ROI of the left wedges (r=-0.568) and the central anterior gyrus of the right frontal lobe (r=-0.563). Conclusions: Patients with IXT exhibit decreased gray matter volume in the horizontal connection areas between the primary visual cortices V1 and V2. The reduction in gray matter volume of the lingual gyrus and the dorsal visual pathway V3 area becomes more pronounced with increasing exotropia severity, while the gray matter volume of the precentral gyrus (BA6 area) decreases with worsening stereoacuity.

Stereoacuity and Aniseikonia: Evaluation Before and After Bilateral Implantation of Three Types of Presbyopia-Correcting Intraocular Lenses in Uncomplicated Phacoemulsification with Due Consideration of Interocular Differences in Higher Order Aberrations, Axial Lengths, Refractive Errors, and Acuities

Stereoacuity and Aniseikonia: Evaluation Before and After Bilateral Implantation of Three Types of Presbyopia-Correcting Intraocular Lenses in Uncomplicated Phacoemulsification with Due Consideration of Interocular Differences in Higher Order Aberrations, Axial Lengths, Refractive Errors, and Acuities

Ocular Manifestation of the Pediatric Age Group in Almarj

Children are disproportionately affected by visual disorders like refractive errors, amblyopia, and strabismus. Early intervention and vision screening are crucial. The study aims to investigate the ocular manifestation among children of the age group 4–15 years. A cross-sectional study conducted at Marj Teaching Hospital in 2024 examined 100 children with ophthalmological conditions. The examinations included slit lamp examinations, visual acuity assessments, spherical refractive error measurements, and dilated retinal exams. The study examined children aged 4-15 years old, with 59% being male and 43% female. Diagnosis revealed a range of ocular conditions, with astigmatism being the most common at 48%. There were significant differences in visual acuity between males and females (p&lt;0.001), particularly in left eye visual acuity without glasses. There was no significant difference in visual acuity between age groups when wearing or not wearing glasses. However, there was a trend towards better right-eye visual acuity for children aged 4-10 years compared to those aged 11-15 years (p&lt;0.001). Refractive errors with a higher prevalence of simple astigmatism in females compared to males. High hypermetropia was only present in females, suggesting some differences in refractive errors between males and females, particularly hypermetropia. The study emphasizes the significance of regular eye examinations for detecting and addressing visual impairments, and calls for further research into factors contributing to these conditions, particularly male-female differences, to improve eye health and quality of life. we highly advocate assessing the visual acuity of preschool children in order to prevent amblyopia.

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

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. 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. 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. 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.

Understanding Vision Impairment: A Comprehensive Study of Uncorrected Refractive Errors among Primary School Teachers and Pupils in Nongowa Chiefdom, Kenema District, Sierra Leone

Introduction: Uncorrected Refractive Error (URE) is a major concern globally, particularly in developing nations like Sierra Leone, where limited access to eye care services poses challenges. Aim: This study, conducted in Nongowa Chiefdom, Kenema District, Sierra Leone, aimed to investigate the prevalence of URE and associated knowledge, attitudes, and practices among primary school pupils and teachers. Methods: Descriptive cross-sectional designs, incorporating both qualitative and quantitative methods were used. A structured survey questionnaire and visual acuity screening tools were used to assess uncorrected refractive errors among 692 randomly selected participants, data analysis involved descriptive statistics and qualitative content analysis. Results: The study involved 374 pupils and 318 teachers from 145 public and 14 private schools, uncorrected refractive error prevalence was 66%, with hypermetropia most prevalent and blindness at 0.13%. Girls contributed 29% of cases compared to boys' 25%. Ages 5-17 were most affected. Public schools accounted for 91% of cases, with peri-urban areas contributing 24% and urban areas 76%. Economic status and education influenced prevalence. Teachers played a crucial role in promoting eye health education. Economic factors may have influenced observed differences in refractive errors. Conclusion: The study highlighted the multifaceted nature of URE, involving demographic, economic, and educational factors. Addressing these complexities through targeted interventions is crucial for mitigating the burden of visual impairment in the region.

Binocular balance across spatial frequency in anisomyopia

PurposeAnisomyopia is prevalent in myopia and studies have reported it exhibits impaired binocular function. We investigated the binocular balance across spatial frequency in adults with anisomyopia and compared it to in individuals with less differences in refractive error, and examined whether ocular characteristics can predict binocular balance in anisomyopia.MethodsFifteen anisomyopes, 15 isomyopes and 12 emmetropes were recruited. Binocular balance was quantitatively measured at 0.5, 1, 2 and 4 c/d. The first two groups of the observers were tested with and without optical correction with contact lenses. Emmetropes were tested without optical correction.ResultsBinocular balance across spatial frequency in optically corrected anisomyopes and isomyopes, as well as emmetropes were found to be similar. Their binocular balance nevertheless still got worse as a function of spatial frequency. However, before optical correction, anisomyopes but not isomyopes showed significant imbalance at higher spatial frequencies. There was a significant correlation between the dependence on spatial frequency of binocular imbalance in uncorrected anisomyopia and interocular difference in visual acuity, and between the dependence and interocular difference in spherical equivalent refraction.ConclusionAnisomyopes had intact binocular balance following correction across spatial frequency compared to those in isomyopes and emmetropes. Their balance was weakly correlated with their refractive status after optical correction. However, their binocular balance before correction and binocular improvement following optical correction were strongly correlated with differences in ocular characteristics between eyes.

Topical Atropine for Childhood Myopia Control

Clinical trial results of topical atropine eye drops for childhood myopia control have shown inconsistent outcomes across short-term studies, with little long-term safety or other outcomes reported. To report the long-term safety and outcomes of topical atropine for childhood myopia control. This prospective, double-masked observational study of the Atropine for the Treatment of Myopia (ATOM) 1 and ATOM2 randomized clinical trials took place at 2 single centers and included adults reviewed in 2021 through 2022 from the ATOM1 study (atropine 1% vs placebo; 1999 through 2003) and the ATOM2 study (atropine 0.01% vs 0.1% vs 0.5%; 2006 through 2012). Change in cycloplegic spherical equivalent (SE) with axial length (AL); incidence of ocular complications. Among the original 400 participants in each original cohort, the study team evaluated 71 of 400 ATOM1 adult participants (17.8% of original cohort; study age, mean [SD] 30.5 [1.2] years; 40.6% female) and 158 of 400 ATOM2 adult participants (39.5% of original cohort; study age, mean [SD], 24.5 [1.5] years; 42.9% female) whose baseline characteristics (SE and AL) were representative of the original cohort. In this study, evaluating ATOM1 participants, the mean (SD) SE and AL were -5.20 (2.46) diopters (D), 25.87 (1.23) mm and -6.00 (1.63) D, 25.90 (1.21) mm in the 1% atropine-treated and placebo groups, respectively (difference of SE, 0.80 D; 95% CI, -0.25 to 1.85 D; P = .13; difference of AL, -0.03 mm; 95% CI, -0.65 to 0.58 mm; P = .92). In ATOM2 participants, the mean (SD) SE and AL was -6.40 (2.21) D; 26.25 (1.34) mm; -6.81 (1.92) D, 26.28 (0.99) mm; and -7.19 (2.87) D, 26.31 (1.31) mm in the 0.01%, 0.1%, and 0.5% atropine groups, respectively. There was no difference in the 20-year incidence of cataract/lens opacities, myopic macular degeneration, or parapapillary atrophy (β/γ zone) comparing the 1% atropine-treated group vs the placebo group. Among approximately one-quarter of the original participants, use of short-term topical atropine eye drops ranging from 0.01% to 1.0% for a duration of 2 to 4 years during childhood was not associated with differences in final refractive errors 10 to 20 years after treatment. There was no increased incidence of treatment or myopia-related ocular complications in the 1% atropine-treated group vs the placebo group. These findings may affect the design of future clinical trials, as further studies are required to investigate the duration and concentration of atropine for childhood myopia control.

Applied Forces Changed Myopia Lens Optical Performance but Not Retinal Image Quality Tested Using a Newly Designed Digital Colmascope.

The aim of this study was to investigate the effects of applied forces generated by a rim screw on the optical performance of mounted myopia lenses. The residual refractive error and retinal image quality of the corrected eyes were also investigated. For 120 lenses, internal lens stress was measured using a newly designed digital strain viewer (colmascope). Sixty myopic adults (120 eyes) were recruited. The effects of internal lens stress on residual refraction and retinal image quality were evaluated using OPD Scan III. The results were compared between loose and tight mounting and between the right and left eyes. Significant differences were observed among nine lens zones in both the right and left lenses, regardless of the mounting state (P < 0.001). The differences were mainly derived from the five vertically arranged zones (P < 0.05). Significant differences in internal lens stress were observed between the right and left lenses (P < 0.05). No significant differences in central residual refractive error and retinal image quality of the corrected eyes were found between the loose- and tight-mounted lenses. The applied forces generated by the rim screw changed the peripheral optical performance of the mounted myopia lenses but exerted only negligible impacts on the central residual refractive error and visual image quality.

Rates of Fellow Eye Macular Hole Development During Long Term Follow-Up

Identify the long-term rate of fellow eye full-thickness macular hole (FTMH) development. In this single site, single provider retrospective consecutive case series, idiopathic FTMH patients who underwent surgery from 2003 to 2014 who also had at least 5 years of follow-up information within our electronic medical record (EMR) which was started in 2014 were identified. Cases with secondary causes (ie, trauma), high myopia, bilateral FTMH on presentation, previous retinal surgery, retinal breaks, or intraocular inflammation were excluded. Demographics, medical and ocular history, refractive error, phakic status, best corrected visual acuity, follow-up duration, surgical technique, single operation anatomic success, and reoperations were recorded. The rate of fellow eye FTMH was 2.6% (2/77) at 1 year, 5.2% (4/77) at 3 years, 9.1% (6/66) at 6 years, and 9.1% (7/77) as of final follow up. There were 2 cases by year 1, 2 additional cases by year 3, 2 additional cases by year 6, and 1 additional case reported thereafter. The average follow up was 11.1 ± 4.5 years. There was no significant difference in visual outcomes between primary eyes and fellow eyes. There was no significant difference in gender, age, ocular comorbidities, refractive error, phakic status, and visual acuity between the unilateral and bilateral groups. The rate of FTMH in the fellow eye was low but significant, increased during long-term follow up, and may stabilize after 6 years.

Non-cycloplegic refraction cannot replace cycloplegic refraction in primary school children.

The purpose was to assess the differences in spherical equivalent refractive error (SER) between cycloplegic autorefraction (1% cyclopentolate), non-cycloplegic autorefraction, and non-cycloplegic retinoscopy measured by experienced optometrists in a population with a high prevalence of hyperopia. Refractive error was measured with the three methods in 111 children aged 7–8 and 10–11 years. Bland-Altman analysis was used to assess the mean of the differences (MD) and the 95% limits of agreement (LoA) between cycloplegic autorefraction and the two non-cycloplegic methods. A mixed effects model was used to investigate the differences between methods by refractive group. Cycloplegic autorefraction gave a significantly more positive SER than both non-cycloplegic retinoscopy (MD = 0.47 D, LoA = -0.59–1.53 D) and non-cycloplegic autorefraction (MD = 0.92 D, LoA of -1.12 to 2.95 D). The mean differences in SER increased with increasing degree of hyperopia [F(4, 215) = 12.6, p &lt; .001], both when comparing cycloplegic refraction with non-cycloplegic retinoscopy and non-cycloplegic autorefraction.&#x0D; Non-cycloplegic retinoscopy and autorefraction result in significantly less positive SER than cycloplegic autorefraction. The wide confidence intervals for the mean difference and limits of agreement are clinically unacceptable and the methods cannot be used interchangeably. Consequently, refraction without cycloplegia would cause misdiagnosis in some children. Even if non-cycloplegic retinoscopy results in narrower limits of agreement, the risk of misdiagnosis is not eliminated by being experienced in carrying out retinoscopy. We show that it is essential to use cycloplegia when refracting children, and in particular to ensure that no hyperope goes undetected.

Intraocular Amphiregulin antibody and axial elongation in nonhuman primates.

To examine the effect of intraocularly applied amphiregulin antibody on physiological axial elongation in young nonhuman primates. The experimental study included six male 12-months-old macaque nonhuman primates (body weight:2.46 ± 0.25kg;range:2.20-2.90kg). In the experimental group (n=3 animals), three intravitreal injections of amphiregulin antibody (100μg/50μl) were applied to the left eyes at intervals of 4-6 weeks, and injections of phosphate buffered solution (50μl) were applied to the right eyes. Three other animals were assigned to a blank control group. During the study period of 23.6 weeks, axial length in the experimental group did not change in the left eyes (18.91 ± 0.37mm to 18.94 ± 0.67mm;P=0.90), while it linearly increased in the right eyes (18.87 ± 0.38mm to 19.24 ± 0.53mm;P=0.056) and in the control group (left eyes:19.15 ± 0.22mm to 19.48 ± 0.22mm;P=0.009; right eyes:19.17 ± 0.15 mm to 19.46 ± 0.23 mm;P=0.024). The interocular difference in axial elongation increased in the experimental group from -0.11 ± 0.12mm at 4 weeks after baseline to -0.34 ± 0.15mm at the study end, while in the control group, the interocular side difference did not change significantly (from 0.01 ± 0.10 mm to 0.03 ± 0.08 mm;P=0.38). The difference in the interocular difference in axial elongation between the two groups was significant at 8 weeks (P=0.01), 15 weeks (P=0.007), and at study end (P=0.02). The interocular difference in axial length correlated with the interocular difference in vitreous cavity length (standardized regression coefficient beta:0.85;P<0.001). The interocular axial length difference was inversely associated with the interocular refractive error difference (beta:-0.49;P<0.001). Intraocularly applied amphiregulin antibody (100μg) reduced the physiological ocular axial elongation in juvenile nonhuman primates.

Refractive error in unilateral Duane syndrome

Research on the effect of strabismus surgery on refraction suggests that tension exerted on the globe by extraocular muscles influences refractive error. We studied differences in refractive error between Duane and fellow eyes in patients with unilateral Duane syndrome. We hypothesized that chronic co-contraction of the medial and lateral rectus muscles leads to higher astigmatism in Duane versus fellow eyes.

Depth of field and visual performance after implantation of a new hydrophobic trifocal intraocular lens

PurposeTo assess the depth of field (DOF) by means of defocus curve analysis applying different visual acuity criteria in patients following cataract surgery and bilateral implantation of a new trifocal diffractive intraocular lens (IOL).MethodsFifty eyes of 25 consecutive patients who underwent implantation of the Asqelio™ trifocal IOL (AST Products Inc., USA) were enrolled in this observational prospective study. Monocular subjective DOF was obtained from defocus curves with absolute and relative criteria of tolerance for different visual acuities values. Patient’s visual satisfaction, postoperative refraction and visual acuity at far, intermediate (67 cm) and near (40 cm) distances were also measured at 1 and 3-months post-surgery. Analysis of variance was used to assess differences in refractive error after the surgical procedure, and paired t-tests were used to assess differences in VA. Patient satisfaction results were reported as percentages.ResultsSpherical equivalent was 0.05 ± 0.23 D and residual cylinder 0.01 ± 0.23 D 3-months after the surgery. Absolute DOF obtained was 3.29 ± 0.91 D considering 0.1 LogMAR as cut-off value, and 4.82 ± 0.69 D when 0.3 logMAR as cutoff value. Relative DOF considering a drop of 0.1 logMAR from maximum visual acuity was 2.57 ± 0.82 D, and 1.27 ± 0.70 D when a drop of 0.04 logMAR was considered. Visual acuities obtained 3-months after the surgery were 0.03 ± 0.13, − 0.05 ± 0.06, 0.03 ± 0.08 and 0.04 ± 0.08 logMAR for uncorrected and best-corrected for distance, and best distance-corrected for intermediate and near distances, respectively. Average response to visual satisfaction queries was 8.24/10 at distance, 8.04/10 at intermediate, and 7.88/10 at near.ConclusionsPatients implanted with this trifocal IOL showed a significant improvement in visual acuity at different distances providing wide absolute and relative DOF values. The outcomes demonstrate that this lens is predictable yielding good patient satisfaction rates.

Association of School Education With Eyesight Among Children and Adolescents

Myopia in youths is an increasingly common global problem, associated with significant social and economic burden worldwide. To explore the association of school education with myopia and investigate its scale, controlling confounding factors, such as age and socioeconomic status. This cross-sectional study was conducted from July 2019 to December 2020 using regression discontinuity (RD) based on the Compulsory Education Law to examine the complex association of school education with myopia. Participants were youths from grades 1 to 12 before tertiary or university studies in China, including individuals from 815 primary schools, 373 junior high schools, and 145 senior high schools. Data were analyzed from February through June 2021. Participants born earlier in a year (ie, January to August) were assigned 1 more year of education and were considered to be in the treated group, while participants born September to December were considered to be in the control group. Differences in mean spherical equivalent refractive error (MSE) and uncorrected visual acuity (UVA) between treated and control groups were calculated. Among a mean (SD) of 812 979 (55 953) participants across 5 surveys survey (mean SD 44.9% [0.5%] female participants; mean [SD] age, 11.19 [2.60] years), the mean (SD) MSE was -1.30 (2.93) diopters and mean (SD) UVA was 4.77 (0.34) points. Every additional year at school was associated with an decrease in MSE of -0.17 diopters/y (95% CI, -0.22 to -0.11 diopters/y) and a decrease in UVA of -0.03 points/y (95% CI, -0.04 to -0.02 points/y), which accounts for nearly 66.4% (95% CI, 85.9% to 43.0%) and 78.9% (95% CI, 102.6% to 55.3%) of changes of MSE and UVA, respectively, among all factors for youths. The greatest MSE shifts occurred in grades 3 and 7 (eg, for the June 2019 census, the RD was -0.26 diopters/y [95% CI, -0.33 to -0.20 diopters/y] for grade 3 and -0.41 diopters/y [95% CI, -0.66 to -0.15 diopters/y] for grade 7). These findings suggest that receiving more years of education, instead of age, may be a risk factor associated with myopia progression in youths.

A STUDY OF MAGNITUDE OF ANISOMETROPIA AND ITS ASSOCIATION WITH AMBLYOPIA IN SCHOOL GOING CHILDREN

BACKGROUND: Visual impairment is a common handicap among school going children. In some, there are signicant interocular differences in refractive error (ANISOMETROPIA), which can be accompanied by an interocular difference in visual acuity that is optically uncorrectable ( AMBLYOPIA). The co-occurrence of these two anomalies with no additional abnormality is ANISOMETROPIC AMBLYOPIA. Present study is aimed to study magnitude ofANISOMETROPICAMBLYOPIAin children. OBJECTIVES: To study the magnitude ofAnisometropia and its association with amblyopia in school going children. To identify amblyopic children and provide suitable treatment. MATERIALS AND METHOD: A cross- sectional study done over a period of 18 months at a tertiary health care center. School going children of age 7-17 years with refractive error were assessed of their refractive status, ocular examination including slit lamp examination and fundoscopy was done. Children with interocular refractive error difference of &gt;0.75 D were labelled as Anisometropic. Children whose best corrected visual acuity difference of both the eyes was more than two lines on Snellen's chart in absence of other organic cause were considered Amblyopic. Prevalence of anisometropia and its relation with amblyopia was determined. Data were analyzed by Chi-square test .Appropriate refractive correction was given. RESULT: Out of 100 ametropic children, 14 were anisometropic. Out of 14 anisometropic children 5 were amblyopic .Association between anisometropia and amblyopia was statistically signicant (p value &lt; 0.05). It was found that as severity of anisometropia increases, predisposition of development of amblyopia also increases. CONCLUSION:Refractive ansiometropia has a considerable prevalence and is a well-known amblyogenic factor in children. Timely intervention should be done to prevent permanent vision loss.

Magnitude of Prevelance of Refractive Errors in School-age Children: A Cross-sectional Study

Aim: To determine the frequency of refractive errors in school-age children.&#x0D; Study Design: Cross-sectional study.&#x0D; Place and duration: Two Government and two Private schools of Hyderabad Sindh, screened by the institute of ophthalmology at Liaquat University of Medical and Health Sciences Jamshoro, from January 2021 to June 2021.&#x0D; Methodology: Schools and students were selected by stratified random method; a total of four hundred students were screened in four schools. From class one to class ten, 10 students were selected from each class. Prior written permission was obtained from parents. External ocular examination, visual acuity, pinhole test, autorefraction, and fundus examination were done and recorded on proforma along with the information regarding age, sex, family history, and parent’s education. The data was entered and analyzed by SPSS version 22.&#x0D; Results: In government schools 27 students out of 200 had refractive errors, myopia was present in 15 (55.55%) students, hypermetropia in 7 (25.93%) students and astigmatism in 5 (18.52%) students, while in private schools 25 students had refractive errors. Myopia was present in 16 (64%) students, hypermetropia in 7 (28%) students and astigmatism in 2 (8%) students. Myopia and astigmatism were more prevalent in female sex being 8.1% and 2% respectively, while in males it was 6.4% and 1.4% cases. In this study, no significant refractive error difference was found between government and private sector schools.&#x0D; Conclusion: In our study, the prevalence of refractive errors was 13% (52) out of 400 students. Refractive errors are the most common and easily treatable causes of decreased vision in school-aged children. It is recommended that visual acuity be checked prior to admission to school because refractive errors can be easily corrected with glasses. If it is treated in time, the child can be prevented from amblyopia and squint.

The difference between the cycloplegic and noncycloplegic refractive error may be an indicator for the myopia progression in myopic children

Aim: We aimed to evaluate the relationship between the subjective and objective refractive error measurement difference and myopia progression in this study.&#x0D; Material and Method: Children between 6-18 year-old at the beginning of the follow-up period having myopia and who were followed up regularly every six months and for a total of at least 36 months were included in the study. All children underwent a detailed ophthalmologic examination. An autorefractor (TOPCON KR1/RM1, Topcon, Oakland, New Jersey), was used to evaluate the refractive error. Those with a refractive error difference of less than 0.50 D (spherical equivalent) before and after cycloplegia were included in group 1. Those with a refractive error difference of higher than 0.50 D were included in group 2. Myopic progression of the groups was compared.&#x0D; Results: This study comprised 44 patients (male, 23; female, 21) in group 1 and 42 patients (male, 22; female, 20) in group 2. The age range and mean age±SD of patients in group 1 were 6-17 years and 11.4±3.0 years, respectively, whereas that of patients in group 2 was 6-17 years and 12.6±3.3 years, respectively. Both groups were followed for similar periods (p= 0.141). It was 37.5±2.4 (range 36-48) months in group 1 and 36.8±1.6 (range 36-42) months in group 2. The range and mean of the cycloplegic refractive error at the beginning of the following period in group 1 were -2.37±1.15 D, and -1.75±0.99 D in group 2 respectively (p= 0.010). At the end of the following period, the mean cycloplegic refractive error were -2.73±1.11 D in group 1, and -3,33±0.91 D in group 2 respectively (p= 0.008). During follow-up, the change in cycloplegic refractive error was 0.36±0.16 D in group 1, and 1.57±0.46 D in group 2. It was significantly lower in group 1 than group 2 (p&lt; 0.0001).&#x0D; Conclusion: We demonstrated that myopic children having high baseline difference between the objective and subjective spheric equivalent measurements had more myopia progression.

Stereopsis, Aniseikonia, and Associated Symptoms in Patients with Bilateral Pseudophakia with and without Anisometropia: A Comparative Study

Objectives: The study aimed to compare stereopsis, aniseikonia, and associated symptoms in bilateral pseudophakia with and without anisometropia. Methods: Patients with senile cataracts, previously scheduled for phacoemulsification with an IOL implant in both eyes were included in this cross-sectional study. Patients were divided into two groups: control group (n = 69) with an interocular post-surgical refraction difference in Spherical Equivalent (SE) TM 3 and stereopsis by Randot?; Stereotest. Ten symptoms related to aniseikonia were evaluated with a questionnaire. Statistical evaluation of data included models of univariate, multivariate, and regression analyses. Results: Cataract surgery-induced aniseikonia was 0.64% ± 1.41% in control group and 0.62% ± 1.76% in anisometropia group with an insignificant difference (p = 0.766). Measured stereoacuity was 1.95 ± 0.17 log10 seconds of arc in the control group and 2.12 ± 0.22 log10 seconds of arc in the anisometropia group with a significant difference (p < 0.0001). The mean score of symptoms associated with aniseikonia was 1.41 ± 0.46 in the control group and 1.47 ± 0.45 in the aniso- metropia group, with an insignificant difference (p = 0.387). The contribution of independent variables in predicting stereopsis in the anisometropia group was the following: axial length difference (18.06%); refractive error difference (SE) (44.53%), aniseikonia (25.71%), and IOL power difference (11.71%). Conclusions: The study showed that stereopsis, aniseikonia, and associated symptoms did not stand for a substantial problem for visual comfort of bilateral pseu- dophakia with anisometropia less than 3D.

Melanopsin modulates refractive development and myopia

Myopia, or nearsightedness, is the most common form of refractive abnormality and is characterized by excessive ocular elongation in relation to ocular power. Retinal neurotransmitter signaling, including dopamine, is implicated in myopic ocular growth, but the visual pathways that initiate and sustain myopia remain unclear. Melanopsin-expressing retinal ganglion cells (mRGCs), which detect light, are important for visual function, and have connections with retinal dopamine cells. Here, we investigated how mRGCs influence normal and myopic refractive development using two mutant mouse models: Opn4−/− mice that lack functional melanopsin photopigments and intrinsic mRGC responses but still receive other photoreceptor-mediated input to these cells; and Opn4DTA/DTA mice that lack intrinsic and photoreceptor-mediated mRGC responses due to mRGC cell death. In mice with intact vision or form-deprivation, we measured refractive error, ocular properties including axial length and corneal curvature, and the levels of retinal dopamine and its primary metabolite, L-3,4-dihydroxyphenylalanine (DOPAC). Myopia was measured as a myopic shift, or the difference in refractive error between the form-deprived and contralateral eyes. We found that Opn4−/− mice had altered normal refractive development compared to Opn4+/+ wildtype mice, starting ∼4D more myopic but developing ∼2D greater hyperopia by 16 weeks of age. Consistent with hyperopia at older ages, 16 week-old Opn4−/− mice also had shorter eyes compared to Opn4+/+ mice (3.34 vs 3.42 mm). Opn4DTA/DTA mice, however, were more hyperopic than both Opn4+/+ and Opn4−/− mice across development ending with even shorter axial lengths. Despite these differences, both Opn4−/− and Opn4DTA/DTA mice had ∼2D greater myopic shifts in response to form-deprivation compared to Opn4+/+ mice. Furthermore, when vision was intact, dopamine and DOPAC levels were similar between Opn4−/− and Opn4+/+ mice, but higher in Opn4DTA/DTA mice, which differed with age. However, form-deprivation reduced retinal dopamine and DOAPC by ∼20% in Opn4−/− compared to Opn4+/+ mice but did not affect retinal dopamine and DOPAC in Opn4DTA/DTA mice. Lastly, systemically treating Opn4−/− mice with the dopamine precursor L-DOPA reduced their form-deprivation myopia by half compared to non-treated mice. Collectively our findings show that disruption of retinal melanopsin signaling alters the rate and magnitude of normal refractive development, yields greater susceptibility to form-deprivation myopia, and changes dopamine signaling. Our results suggest that mRGCs participate in the eye's response to myopigenic stimuli, acting partly through dopaminergic mechanisms, and provide a potential therapeutic target underling myopia progression. We conclude that proper mRGC function is necessary for correct refractive development and protection from myopia progression.

Functional optical zone after wavefront-optimized versus wavefront-guided laser in situ keratomileusis.

Many studies have used functional optical zone (FOZ) as a measure to compare different refractive laser treatment modalities. However, to our knowledge, no study has compared wavefront- optimized (WFO) and wavefront-guided (WFG) laser in situ keratomileusis (LASIK) using FOZ. We compared the FOZ after WFO versus WFG LASIK in patients with myopia and myopic astigmatism. In this prospective comparative study, we included 100 myopic eyes of 50 patients with or without astigmatism. They were divided into two groups according to the platform used: WFO or WFG femtosecond LASIK. Using Holladay's equivalent keratometry reading (EKR) report of Pentacam HR, FOZ was defined as a zone centered on the pupil center with a standard deviation (SD) of 0.5 D, around the mean EKR. The differences in FOZ between the two platforms were analyzed at 3 months postoperatively. Visual acuity, refractive error, corneal asphericity (Q-value), and root mean square of higher-order aberrations (RMS for HOAs) were evaluated and compared. The mean (SD) of patient age was 26.64 (5.67) years. The preoperative characteristics of the two groups were comparable (all P > 0.05). The intended optical zone (IOZ) was 6 mm in both groups. The mean laser ablation depth was significantly greater in the WFG group (18 µm per D) than in the WFO group (16 µm per D) (P = 0.035). At 3 months postoperatively, the mean (SD) of FOZ diameter was 4.32 (0.94) mm (71.99% [15.68%] of intended optical zone) in the WFO group and 4.16 (1.13) mm (69.33% [18.78%] of intended optical zone) in the WFG group, with no significant difference between the two groups (P = 0.622). The change in corneal asphericity was greater in the WFG group than in the WFO group (P = 0.034). Postoperative mean corrected and uncorrected distance visual acuity, manifest refraction, and RMS for HOAs showed no significant difference between the two groups (all P > 0.05). We found that WFG LASIK resulted in greater ablation depth and change in corneal asphericity than WFO LASIK at 3 months postoperatively. However, there was no significant difference in FOZ diameter, refractive error, and RMS for HOAs between the two groups. Further research is needed to confirm these findings.