Cylindrical Anisometropia Research Articles

Correlation of Refractive Error with Anisometropia Development in Early Childhood

This study aims to investigate the relationship between the type and severity of refractive error and anisometropia development in preschool children. Retrospective cohort study. Data from Maccabi Healthcare Services, Israel's second-largest Health Maintenance Organization (HMO), were analyzed. The study included all isometropic children aged 1 to 6 years, re-examined for refraction at least 2 years following their initial examination between 2012 and 2022. Anisometropia was defined as a ≥1 diopter interocular difference in spherical equivalent. Relationships were assessed using logistic regression models adjusted for key sociodemographic factors. Among 33,496 isometropic children (51.2% male, mean age 3.2 ± 1.5 years), the prevalences of emmetropia, myopia, and hyperopia were 26.7% (n = 8944), 4.2% (n = 1397), and 69.1% (n = 23,155), respectively. Over a mean follow-up period of 5.1 ± 2.4 years, 2593 children (7.7%) were diagnosed with anisometropia. Adjusted odds ratios (ORs) for anisometropia gradually increased with baseline refractive error severity, reaching 13.90 (5.32-36.34) in severe myopia and 4.19 (3.42-5.15) in severe hyperopia. This pattern was also evident in cylindrical anisometropia, where ORs increased with greater baseline astigmatism, peaking at 12.10 (9.19-15.92) in children with high astigmatism (≥3 D). Associations remained consistent in sensitivity and subgroup analyses including across both sexes and when using a stricter anisometropia criterion. Children aged 1 to 6 years, initially without anisometropia but showing increasing severity of myopia, hyperopia, or astigmatism, are more likely to develop anisometropia. This underscores the importance of follow-up refractive measurements within this population to promptly diagnose and treat anisometropia and prevent potential visual complications.

Temporal trend of anisometropia incidence in Chinese school-aged children before and during the COVID-19 pandemic.

To analyze and compare the temporal trends in the incidence of anisometropia among Chinese school-aged children both before and during the COVID-19 pandemic, and to investigate the impact of the pandemic on the incidence of anisometropia. We conducted a retrospective study comprising six distinct and independent longitudinal cohorts, each including children aged 6 to 13 years who visited the Joint Shantou International Eye Center between January 2010 and December 2021. Children were grouped into cohorts based on the year of their first eye clinic visit: 2010, 2012, 2014, 2016, 2018, or 2020. Only children without anisometropia at initial visits, followed for 18 ± 6 months, were included. The cumulative incidence and risk factors of anisometropia were analyzed using Kaplan-Meier estimation and Cox proportional hazards regression models. Subgroup analyses were performed based on sex, age groups, initial refractive error status, and initial interocular SE difference. Anisometropic children were further categorized into myopic and non-myopic, with subsequent subgroup analyses conducted. Of 11,235 children were recruited from six cohorts (2010: n = 1,366; 2012: n = 1,708; 2014: n = 1,896; 2016: n = 2,354; 2018: n = 2,514; 2020: n = 1,397), 869 children developed anisometropia during a mean follow-up of 17.5 ± 3.7 months. After adjustment of confounding factors, we found that the risk of anisometropia remained relatively stable before 2020 but significantly increased in the 2020 cohort (adjusted HR 2.93, 95% CI 2.23 to 3.86; p < 0.001). This trend persisted in studies of spherical anisometropia (adjusted HR 2.52, 95% CI 1.60 to 3.97; p < 0.001) and cylindrical anisometropia (adjusted HR 2.91, 95% CI 1.69 to 3.62; p < 0.001). Older age and a greater initial difference in SE between the two eyes were also significantly associated with a higher risk of developing anisometropia (p < 0.001). Subgroup analyses consistently showed increased risk in the 2020 cohort. This study reveals a concerning rise in anisometropia incidence among Chinese school-aged children during the period of the COVID-19 pandemic. These findings highlight the worrisome rise in anisometropia risk during the COVID-19 pandemic and emphasize the importance of early detection and management to safeguard children's visual health.

The Prevalence of Astigmatism and Spectacle Wear in Polish Schoolchildren

ABSTRACT Introduction Unilateral or asymmetric astigmatism is considered a principal refractive error leading to amblyopia and regular eye examinations should be carried out during childhood to prevent visual impairment. The aim of this study was to evaluate the prevalence of astigmatism and spectacle wear among Polish schoolchildren. Methods A cross sectional study was carried out in children aged 6 to 14 years old from 50 schools in Poland. The presence of astigmatism was assessed by non-cycloplegic autorefraction, and defined as a cylinder equal or greater than 0.75 D. Children were classified as living in urban or rural areas according to the school location. Spectacle wear was defined as having spectacles at school. Results The study included 1041 children and 52.3% were girls (n = 544). The mean age was 8.62 ± 2.04 years. The prevalence of astigmatism was 7.3% (95% confidence interval [CI]: 5.8–9.1%). Only 21.7% of children with astigmatism wore spectacles at school. Astigmatism was diagnosed in 8.2% of boys (95% CI: 6.0–11.0%) and 6.4% of girls (95% CI: 4.5–8.8%; p = .13); cylindrical anisometropia was present in 19/76 (25.0%) of children with astigmatism (95% CI: 15.8%–36.3%). Against-the-rule astigmatism was the most common; it was observed in 48.7% of children with astigmatism, followed by with-the-rule astigmatism (44.7%) and oblique astigmatism (6.6%). The prevalence of astigmatism was not linearly correlated with age (r = 0.24; p = .53). Gender, age and place of living were not significantly associated with the presence of astigmatism. Conclusions This study reports a low prevalence of astigmatism in Polish school children. However, the majority of children with astigmatism were uncorrected. Further longitudinal studies are warranted.

Anisometropia and its association with refraction development in highly myopic children

ABSTRACT Clinical relevance Anisometropia can affect visual development in children. Investigations of anisometropia in high myopes would explore potential causes related to anisometropia, highlighting the management of anisometropia in high myopia. Background The prevalence of anisometropia ranged from 0.6% to 4.3% in general paediatric population and from 7% to 14% in myopes. Anisometropia is regarded as an associated factor for myopia development, while myopia progression is a stimulus driving anisometropic development. The purpose of this study was to investigate the prevalence of anisometropia and its association with refraction development in Chinese children with high myopia. Methods In the cohort study, a total of 1,577 highly myopic (spherical equivalent ≤−5.0D) children aged 4–18 years were included. Refractive parameters (dioptre of sphere, dioptre of cylinder, corneal curvature radius, and axial length) of both eyes were measured after cycloplegia. The prevalence and degree of anisometropia were compared among refractive groups (non-parametric tests or chi-square tests), and regression analyses were used to determine associated factors of anisometropia. The statistical significance was set to P < 0.05 (two-tailed). Results In highly myopic children with a mean (standard deviation) age of 13.06 (2.80) years, the proportions of spherical equivalent anisometropia, cylindrical anisometropia and spherical anisometropia ≥1.00 D were 34.5%, 21.9% and 39.9%, respectively. There was more spherical equivalent anisometropia associated with more severe astigmatism (P for trend <0.001). In the multivariate regression analysis, more spherical equivalent anisometropia, cylindrical anisometropia and spherical anisometropia were associated with higher degrees of astigmatism (standard beta = −0.175, −0.148 and −0.191, respectively). More spherical anisometropia was associated with better spherical power (standard beta = 0.116). Conclusion The proportion of anisometropia in highly myopic children was high, compared with previously reported general population, and more severe anisometropia was associated with higher degree of cylindrical power, but not spherical power.

Anisometropia in the 5th and 6th school years

Abstract Introduction Anisometropia is characterized by a refractive inter ocular difference greater than 1.00 dioptre (D). It is the main cause of amblyopia and loss of binocular vision. Its prevalence depends on several factors, being different values in different geographical areas of the world and in different age groups. Objectives To estimate the frequency of anisometropia in children of the 2nd cycle of Basic Education. Methodology A total of 519 children attending the 5th and 6th school years, from Covilhã schools, from urban and rural areas, aged between 9 and 14 years (10.8 ± 0.8 years) were enrolled in the study. The refractive error was measured with a paediatric auto refractometer (Plusoptix), without cycloplegic and in binocular conditions. Anisometropia was defined as the inter ocular difference in spherical equivalent or cylindrical, greater than 1.00 D and a separate analysis for values greater than 2.00 D. Results The sample was symmetrically divided into genders (50.9% Male), between school grade (53% 5th year) and higher in urban areas (70.1%). The prevalence of anisometropia with cut-off points of 1.00 D and 2.00 D was 12.3% and 5.0%, respectively. There was a higher prevalence among males, in rural areas and in 6th grade. The Chi-square test (□2) shows that the difference is statistically significant only between years of schooling, with a higher prevalence in the 6th grade (p = 0.001). Conclusion There was a slightly higher prevalence of spherical and cylindrical anisometropia (5% and 12.3%) than is reported in the literature (rates between 4.4% and 9.4%). The 6th school year presented rates significantly higher than the 5th year, which points out that anisometropia increases with age, as was also advocated by other authors. Visual screening programs in adolescence for the detection of anisometropia are fundamental, since their timely correction allows to safeguard the binocular vision.

Can the Red Reflex Test Detect Unequal Refractive Error?

To determine the accuracy of the red reflex test in the detection of anisometropia. This prospective, single-masked study enrolled new patients younger than the age of 18years who had not undergone pharmacologic pupillary dilation. A fellow who was masked to all clinical informationilluminated both eyes with a direct ophthalmoscope in a darkened room from a distance of 1m, assessing whether the red reflex between the 2 eyes was symmetric or asymmetric. The patient was then dilated, and cylcoplegic refraction was performed by an attending pediatric ophthalmologist. Exclusion criteriaincluded the presence of strabismus, anisocoria, previous intraocular surgery, media opacity, leukocoria, or nystagmus. Sensitivity was compared with a null hypothesized value of 50% using a 1-sided binomial test. Ninety-two patients with a mean age of 7.3years (range 3months to 16years) were enrolled. With spherical anisometropia greater than or equal to 0.125 diopters, the sensitivity of the red reflex test was 90.6% and the specificity was 58.3%. With cylindrical anisometropia greater than or equal to 0.25 diopters, the sensitivity of the red reflex test was 81.3% and the specificity was 70%. Anisometropia greater than 1.5 diopters in spherical equivalent (4 patients, range -10.625 to -2.625) or cylinder (3 patients, range 1.75-2.25) was accurately detected by red reflex testing in each case. The red reflex test can be an accurate screening tool to detect anisometropia when performed by an ophthalmologist.

Efficacy and outcomes of a summer-based pediatric vision screening program

To investigate the prevalence of decreased visual acuity and uncorrected refractive error in school-aged children participating in summer programs. During the summers of 2014-2016, Wills Eye Hospital collaborated with summer programs in Philadelphia to provide vision screenings for underserved children. Parental consent was obtained prior to vision screening. Fail criteria included children in grades K-1 (ages 5-6) with visual acuity worse than 20/40 in either eye, children in grades 2-6 (ages 7-13) with visual acuity worse than 20/30 in either eye, or children with ≥2 lines of interocular difference. If decreased visual acuity was correctable to ≥20/30 by the onsite optometrist, two pairs of free eyeglasses were provided. Children with other ocular abnormalities were referred to pediatric ophthalmology. Of 1,627 children screened, 360 children (22.1%) did not pass vision screening, and 64 (3.9%) were referred. The prevalence of decreased distance visual was 34.1%. Younger children were more likely to have worse visual acuity than older children (OR=0.943; P=0.023; 95% CI, 0.896-0.992). Myopia (73%), astigmatism (56.8%), hyperopia (15.5%), spherical anisometropia (12.5%), and cylindrical anisometropia (11.9%) presented in the 303 children who underwent a manifest refraction. Myopia increased with age (OR=0.818; P=0.001; 95% CI, 0.724-0.922), whereas astigmatism decreased (OR=0.817; P<0.001; 95% CI, 0.728-0.913) with age. Two pairs of glasses were provided to 301 children. Partnership with summer programs and other community initiatives to provide vision screenings facilitates access to eye care ultimately aimed at improving social functioning and academic performance.

The burden of pure anisometropic amblyopia: a cross-sectional study on 2800 Iranians.

To assess the proportion of pure anisometropic amblyopia in a sample Iranian (white) population. A total of 2800 consecutive individuals who presented at a referral eye clinic for any reason were examined for the presence of pure anisometropic amblyopia. Anisometropia was reported when a spherical equivalent refraction difference of at least 1.0 D with or without a cylinder refraction difference of at least 1.0 D was present between the two eyes. Amblyopia was defined as the best-corrected visual acuity of 20/30 or worse or a two-line interocular visual acuity difference between eyes that could not be attributed to any structural ocular pathology or visual pathway abnormality. Subjects were 1528 females and 1272 males with a mean age of 30.25±14.93years (range, 5-65). Amblyopia was diagnosed in 192 cases (6.9%), significantly more frequent among females (7.9 vs. 5.7%, p=0.02). Pure anisometropic amblyopia was present in 6.1% of the study population, significantly more common in patients with spherical hyperopic anisometropia (37.7%) compared to patients with spherical myopic anisometropia (21.3%), cylindrical myopic anisometropia (4.1%), and cylindrical hyperopic anisometropia (15%) (p<0.001). Pure anisometropic amblyopia is a common finding in Caucasians seeking eye care, particularly when anisometropia is of spherical hyperopic subtype.

Refractive Errors and Amblyopia in the UCLA Preschool Vision Program; First Year Results

To report the outcomes of full ophthalmic examination for preschool children in LA County who failed screening with the Retinomax Autorefractor. Retrospective, cross-sectional study. Between August 2012 and May 2013, the University of California Los Angeles (UCLA) preschool vision program screened 11 260 preschool children aged 3-5 years in Los Angeles County using the Retinomax Autorefractor only. Of those, 1007 children who failed the screening were examined by an ophthalmologist on the UCLA Mobile Eye Clinic. Data from the eye examination were recorded for all children. Amblyopia was defined as unilateral if there was ≥2 line interocular difference in the best-corrected visualacuity (BCVA) and as bilateral if BCVA was <20/50 for children <4 years old and <20/40 for children ≥4 years old. Glasses were prescribed for 740 (74%) ofthose examined. Uncorrected visual acuity for allexamined children was 0.4 ± 0.2 (logMAR mean± SD), and BCVA was 0.2 ± 0.1. Of the 88% who underwent cycloplegia, 58% had hyperopia (spherical equivalent [SE] ≥+0.50 diopter [D]), mean of+2.50 D, and 21% had myopia (SE ≤-0.50 D), mean of-1.40 D. A total of 69% hadastigmatism ≥1.50 D, mean of 1.97 D (range 0-5.75). Spherical and cylindrical anisometropia ≥1.00 D were each found in 26% of those examined. Refractive amblyopia was found in 9% of those examined, or 0.8% of the originalpopulation. Of the amblyopic subjects, 77% were unilateral. Screening of preschoolers with the Retinomax led to diagnosis and early treatment of uncorrected refractive errors and amblyopia. By treating children early, amblyopia may be prevented, quality oflife improved, and academic achievements enhanced.

Prevalence and Associations of Anisometropia in Children.

To describe prevalence and associations of anisometropia in children. The cross-sectional school-based study included children aged 4 to 18 years. The study included 6025 (94.7%) of 6364 eligible children. Mean refractive anisometropia was 0.37 ± 0.57 diopters (median: 0.25 diopters; range: 0-7.88 diopters; prevalence [≥1 diopter]: 7.0% ± 0.3%). In multivariate analysis (regression coefficient r: 0.66), higher refractive anisometropia was associated with older age (P < 0.001; β: 0.07; B: 0.01; 95% CI: 0.01-0.02), higher maternal education level (P < 0.001; β: 0.04; B: 0.02; 95% CI: 0.01-0.03), more total time spent indoors reading or writing (P = 0.001; β: 0.04; B: 0.01; 95% CI: 0.01-0.02), larger intereye difference in axial length (P < 0.001; β: 0.57; B: 1.20; 95% CI: 1.15-1.24), shorter mean axial length of both eyes (P = 0.03; β: -0.03; B: -0.02; 95% CI: -0.03 to -0.001), larger intereye difference in best corrected visual acuity (BCVA) (P < 0.001; β: 0.14; B: 1.83; 95% CI: 1.54-2.12), and lower stereoacuity (P < 0.001; β: 0.08; B: 0.31; 95% CI: 0.22-0.39). Refractive anisometropia showed a U-shaped correlation with refractive error. Higher anisomyopia was associated (r: 0.57) with older age (P = 0.001; β: 0.05; B: 0.006; 95% CI: 0.002-0.009), higher level of paternal education (P = 0.001; β: 0.01; B: 0.01; 95% CI: 0.01-0.02), more total time spent indoors reading or writing (P = 0.01; β: 0.03; B: 0.01; 95% CI: 0.00-0.01), larger intereye difference in axial length (P < 0.001; β: 0.22; B: 0.26; 95% CI: 0.23-0.29), greater myopic refractive error (P < 0.001; β: -0.46; B: -0.07; 95% CI: -0.08 to -0.07), and lower corneal astigmatism (P < 0.001; β: -0.10; B: -0.06; 95% CI: -0.08 to -0.05). In the same multivariate model, hyperopic anisometropia was not significantly associated with time spent indoors with reading (P = 0.18). Cylindrical anisometropia (mean: 0.30 ± 0.32 diopters; prevalence [≥1 diopter]: 3.7% ± 0.2%) increased with higher refractive anisometropia (P < 0.001; β: 0.16; B: 0.09; 95% CI: 0.08-0.11), greater myopic refractive error (P < 0.001; β: -0.06; B: -0.01; 95% CI: -0.01 to -0.01), higher corneal astigmatism (P < 0.001; β: -0.22; B: -0.15; 95% CI: -0.17 to -0.13), and lower mean BCVA (P < 0.001; β: 0.11; B: 0.90; 95% CI: 0.68-1.17). In 4- to 18-year-old children, refractive anisometropia and anisomyopia increased with systemic parameters such as age, parental education level, and lifestyle of the children, for example, more time spent indoors reading or writing. In contrast, hyperopic anisometropia and cylindrical anisometropia were not related with lifestyle parameters.

Calibration and Validation of Nine Objective Vision Screeners With Contact Lens-Induced Anisometropia

New objective photoscreeners are emerging with encouraging national guidelines and pediatric providers can be reimbursed for photoscreening. Nine objective screeners were applied to two emmetropic subjects with or without known power contact lenses to induce spherical and cylindrical anisometropia close to American Association for Pediatric Ophthalmology and Strabismus (AAPOS) thresholds. The screeners produced near linear pupil crescents and estimated refractions for induced anisometropia. Most performed well with AAPOS 2003 validation; however, the iPhone (Apple, Cupertino, CA) was too sensitive, whereas the remote autorefractors using Vision in Preschoolers Study criteria were less sensitive. The new, interpreted objective screeners appear valid for detection of anismetropia.

Associations of Anisometropia with Unilateral Amblyopia, Interocular Acuity Difference, and Stereoacuity in Preschoolers

To evaluate the relationship of anisometropia with unilateral amblyopia, interocular acuity difference (IAD), and stereoacuity among Head Start preschoolers using both clinical notation and vector notation analyses. Multicenter, cross-sectional study. Three- to 5-year-old participants in the Vision in Preschoolers (VIP) study (n = 4040). Secondary analysis of VIP data from participants who underwent comprehensive eye examinations, including monocular visual acuity testing, stereoacuity testing, and cycloplegic refraction. Visual acuity was retested with full cycloplegic correction when retest criteria were met. Unilateral amblyopia was defined as IAD of 2 lines or more in logarithm of the minimum angle of resolution (logMAR) units. Anisometropia was defined as a 0.25-diopter (D) or more difference in spherical equivalent (SE) or in cylinder power and 2 approaches using power vector notation. The percentage with unilateral amblyopia, mean IAD, and mean stereoacuity were compared between anisometropic and isometropic children. The percentage with unilateral amblyopia, mean IAD, and mean stereoacuity. Compared with isometropic children, anisometropic children had a higher percentage of unilateral amblyopia (8% vs. 2%), larger mean IAD (0.07 vs. 0.05 logMAR), and worse mean stereoacuity (145 vs. 117 arc sec; all P<0.0001). Larger amounts of anisometropia were associated with higher percentages of unilateral amblyopia, larger IAD, and worse stereoacuity (P<0.001 for trend). The percentage of unilateral amblyopia increased significantly with SE anisometropia of more than 0.5 D, cylindrical anisometropia of more than 0.25 D, vertical and horizontal meridian (J0) or oblique meridian (J45) of more than 0.125 D, or vector dioptric distance of more than 0.35 D (all P<0.001). Vector dioptric distance had greater ability to detect unilateral amblyopia than cylinder, SE, J0, or J45 (P<0.001). The presence and amount of anisometropia were associated with the presence of unilateral amblyopia, larger IAD, and worse stereoacuity. The threshold level of anisometropia at which unilateral amblyopia became significant was lower than current guidelines. Vector dioptric distance is more accurate than spherical equivalent anisometropia or cylindrical anisometropia in identifying preschoolers with unilateral amblyopia.

Association between Ocular Dominance and Spherical/Astigmatic Anisometropia, Age, and Sex: Analysis of 10,264 Myopic Individuals

To determine the association between ocular dominance and spherical or astigmatic anisometropia, age, and sex. Medical records of 10,264 myopic refractive surgery candidates were filtered. Ocular dominance was assessed with the hole-in-the-card test. Manifest refractive error was measured in each subject and correlated to ocular dominance. Only subjects with corrected distance visual acuity (CDVA) of >20/22 in each eye were enrolled, to exclude amblyopia. Associations between ocular dominance and refractive state were analyzed by means of the t-test, χ(2) test, Spearman correlation, and multivariate logistic regression analysis. Right and left eye ocular dominance was noted in 61.7% and 35.6% of the individuals. Ocular dominance had no significant impact on SE refraction in subjects with SE or cylindrical anisometropia <0.5 D. For anisometropia >2.5 D (n = 278) the nondominant eye was more myopic in 63.7% (SE -5.8 ± 2.64 D) compared to 36.3% (-4.69 ± 2.39 D; P < 0.001; adjusted P (Padj) < 0.001) for the dominant eye being more myopic. Nondominant eyes showed higher astigmatic power than dominant eyes (-0.95 ± 0.91 D versus -0.89 ± 0.84 D; P < 0.001). For astigmatic anisometropia >2.5 D, nondominant eyes exhibited a higher amount of astigmatism in 75% of subjects. Nondominant eyes of subjects <29 years and 30 to 39 years of age had a significantly higher astigmatic power than did dominant eyes of the same age group. In contrast to previous reports, this study, including myopic refractive surgery candidates, revealed that the nondominant eye was more myopic for SE anisometropia >2.5 and more astigmatic for cylindrical anisometropia >0.5 D.

Prevalence and Risk Factors for Anisometropia in the Tehran Eye Study, Iran

Purpose: To determine the prevalence of anisometropia and its determinants in a population-based sample.Methods: In a cross-sectional population-based study, stratified cluster sampling was carried out from the population of Tehran. Respondents were transferred to a clinic for an interview and ophthalmic examinations including tests for visual acuity with and without correction, cycloplegic refraction, the slit lamp examination, fundoscopy, and lensometry. Anisometropia was defined as unequal spherical equivalent cycloplegic refractions in the two eyes.Results: Of 4565 participants, cycloplegic refraction was performed in both eyes of 3519 people. The mean age of the examinees was 31.5 ± 18.0 (range, 5–86) years. The mean anisometropia was 0.34 diopter (D) (95% Confidence Interval (CI): 0.31–0.37). The prevalence rates of anisometropia more than 0.5, 1.0, 1.5 and 2.0 D were 18.5% (95% CI: 17.0–19.9), 6.7% (95% CI: 5.8–7.7), 3.8% (95% CI: 3.1–4.5) and 2.6% (95% CI: 2.1–3.1). The inter-gender difference in the prevalence of anisometropia ≥ 1.0D was not statistically significant (P = 0.952). The prevalence of anisometropia increased after the age of 45 years. Overall, 15.7% of the examinees had anisomyopia and 4.7% had anisohypermetropia equal to or more than 1.0D. Anisometropia was more prevalent among patients with cataracts, amblyopia, and pseudophakia. The prevalence rates of spherical and cylindrical anisometropia in the studied sample were 8.0% and 7.1%, respectively.Conclusions: The prevalence of anisometropia in the population of Tehran is beyond negligible. It showed a significant increase with age. Results also indicate that myopic patients are more likely to have anisometropia.

Anisometropia in Hispanic and African American Infants and Young Children: The Multi-Ethnic Pediatric Eye Disease Study

To determine anisometropia prevalence and associated risk factors in Hispanic and African American preschoolers.Population-based, cross-sectional study.We included 3030 Hispanic and 2994 African American children aged 6 to 72 months from Inglewood, California.Retinomax autorefraction was performed on all participants after cycloplegia. Anisometropia was defined by difference in spherical equivalent (SE), by difference in plus cylinder in any axis (cylindrical), and by difference in cylinder axis vectors (vertical Jackson cross cylinder vector [J0] and oblique Jackson cross cylinder vector [J45] between the eyes. Strabismus was determined by prism-cover testing. A parental questionnaire explored potential risk factors including developmental delay, prematurity, prenatal exposure, and family history.Anisometropia prevalence stratified by age, gender, and ethnicity. The association of anisometropia with strabismus and other biological risk factors was assessed.The prevalence of SE anisometropia > or =1.0 diopter (D) was 4.3% for Hispanics and 4.2% for African Americans. Prevalence of cylindrical anisometropia > or =1.0 D was 5.6% and 4.5%, respectively. Prevalence of cylindrical or SE anisometropia > or =3.0 D was < or =0.4% for both ethnic groups. Cylinder vector anisometropia > or =0.5 was twice as common as cylindrical anisometropia > or =1.0 D. The SE anisometropia decreased at age 1 year in Hispanics (P = 0.0016) but not African Americans. Cylindrical anisometropia decreased in the first year of life in both ethnic groups (P < or = 0.001). There was no trend in SE or cylindrical anisometropia beyond 1 year of age, but cylinder vector anisometropia steadily decreased beyond 1 year of age in both ethnic groups. Cylinder vector anisometropia was more prevalent among African Americans, but there was no difference in other measurements of anisometropia between ethnic groups. Anisometropia did not vary by gender. Strabismus was associated with all types of anisometropia. No association of anisometropia with gestational age, birth weight, cerebral palsy, family history, or prenatal exposure could be identified.Spherical and cylindrical anisometropia (> or =1.0 D) each affect 4% to 6% of Hispanic and African American preschoolers. Anisometropia > or =3.0 D is rare. Except for cylinder axis vector, the prevalence of anisometropia does not diminish beyond 1 year of age. Strabismus is associated with all forms of anisometropia.The authors have no proprietary or commercial interest in any of the materials discussed in this article.

The Association Between Amblyopia and Anisometropia in Intermittent Exotropia

Purpose: To determine the frequency of amblyopia and anisometropia in intermittent exotropia and to evaluate the relationship between anisometropia and amblyopia. Methods: The medical records of 471 intermittent extotropia patients, who were followed up over a period of 6 months and ranged from 3 to 15 years of age had been retrospectively reviewed. Anisometropia patients, who had either spherical or cylindrical anisometropia of more than 1.00D, were divided into 4 groups: spherical hyperopic anisometropia (SHA), spherical myopic anisometropia (SMA), cylindrical hyperopic anisometropia (CHA), and cylindrical myopic aniometropia (CMA). Results: The frequency of amblyopia in the intermittent exotropia group was 41/471 (8.7%). Amblyopia results in a significant increase in the incidence of anisometropia and a decrease in binocular function when compared with non-amblyopic patients. In the amblyopia group, 14 patients had anisometropia (34.1%) consisting of 2 patients with spherical myopic anisometropia (SMA), 2 patients with spherical hyperopic anisometropia (SHA), 2 patients with cylindrical myopic anisometropia (CMA) and 8 patients with cylindrical hyperopic anisometropia (CHA). In the anisometropia group (n=56) 14 patients (25.0%) had amblyopia and in the non‐anisometropia group (n= 415) 27 patients (6.5%) had amblyopia. Conclusions: Intermittent exotropia is susceptible to amblyopia, especially when combined with anisometropia. Among the 4 types of anisometropia, cylindrical hyperopic anisometropia has a higher risk for developing amblyopia.

Refractive error after spontaneously regressed retinopathy of prematurity

Introduction: Retinopathy of prematurity (ROP) is a potentially blinding disease of the eye. Even with spontaneously regressed disease, frequent examination is often performed to detect high refractive error, anisometropia, and strabismus. However, there is a paucity of evidence-based guidelines that suggest appropriate follow-up intervals for these children. We reviewed the development of ametropia after a normal first examination in children with spontaneously regressed ROP. Methods: Retrospective chart review. A normal cycloplegic refraction was defined as hyperopia less than 3.5 D without spherical or cylindrical anisometropia greater than 1.5 D. Results: 760 children were identified with a diagnosis of ROP. Of those, 428 were examined by a pediatric ophthalmologist with cycloplegic refraction prior to 18 months of age. Children with a history of threshold ROP and those with strabismus or structural abnormality of the eye were then excluded. 226 children were found to have a normal eye examination and cycloplegic refraction. Of those, 84 had a second visit with cycloplegic refraction an average of 23.9 months after the initial visit. 63 children had a normal second examination by the criteria above and 21 developed minimal symmetric myopia (<1.5 D). Three (3.6%) children were found to have significant refractive errors requiring spectacles: 2 with anisometropia and 1 with myopic astigmatism. Conclusions: Children with spontaneously regressed ROP and low hyperopia at first examination have a similar risk of ametropia as the general population. Such children can likely be followed with routine vision screening in the pediatrician’s office.

Ocular anisometropia and laterality.

To study the difference in refraction between right and left eyes (anisometropia) in different age groups, look for evidence of eye laterality (more refractive error in one eye) and compare the size of anisometropia in the myopic and emmetropic ranges. The study was based on children in Hong Kong (examined at the age of 6 years and again at the age of 8.5 years) and their parents (aged 26-60 years). In all age groups the difference between right and left eyes in sphere and cylinder was modest, in most cases < or = 0.25 D. In both children and their parents a tendency towards spherical right eye laterality was found in the myopic individuals (p < 0.05). This was not the case with the cylinder. In the 8.5-year-old children and in their parents, the numerical size of spherical anisometropia increased with myopia (p < 0.05 and p < 0.01, respectively). Cylindrical anisometropia did not exhibit such an increase. In Hong Kong children and their parents we found a tendency towards more spherical myopia in right eyes (laterality) in myopic cases. The numerical size of spherical anisometropia also increased in myopia in these groups. Cylindrical anisometropia appeared to be independent of spherical ametropia. In most cases right/left differences in both sphere and cylinder were small and our findings justify the use of data from one eye only in publications on refraction.

Non-cycloplegic screening for refractive errors in children with the hand-held autorefractor Retinomax: Final results and comparison with non-cycloplegic photoscreening

AIMS. To establish the results of refractive screening of preschool children with the hand-held autorefractor Retinomax under non-cycloplegic conditions, and to compare these results with those of photoscreening. METHODS. Among 1218 children undergoing non-cycloplegic refractive screening, 302 (25%) were also refracted under cycloplegia using the same refractor and were used as controls. Our criteria for a positive screening test were based on the spherical or cylinder values and were: myopia over 3D, astigmatism = 2D, spherical or cylindrical anisometropia = 1.5D, and hyperopia = 1.5D. Absolute myopia over 3D, absolute astigmatism = 2D, absolute anisometropia = 1.5D and absolute hyperopia > 3.5D were considered as true positives. The sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated within the group of controls for each refractive anomaly. On the basis of Bayes' theorem, these figures were then corrected to yield the true screening results that would be expected in a population without verification and selection bias. To determine the usefulness of this screening technique, the likelihood ratios for positive test results (+LR) were also calculated. The results of this screening in terms of sensitivity, specificity and predictive values were then compared with those of photoscreening. RESULTS. The basic results of screening with the hand-held autorefractor were as follows: –ÊHyperopia: sensitivity 46%, specificity 97%, PPV 55%, NPV 96%, +LR 15; –ÊAstigmatism: sensitivity 37%, specificity 99%, PPV 69%, NPV 96%, +LR 37; –ÊAnisometropia: sensitivity 66%, specificity 93%, PPV 19%, NPV 99%, +LR 9; –ÊMyopia: sensitivity 87%, specificity 99%, PPV 33%, NPV 100%, +LR 87. The comparison with photoscreening revealed a similar performance when screening for hyperopia, but the hand-held autorefractor yielded much better figures when screening for astigmatism. In the case of myopia and anisometropia, the lack of consistent information concerning photoscreening invalidates any comparison. CONCLUSION. The hand-held autorefractor Retinomax appears to have potential as a screening device. Our experience with the non-cycloplegic screening of preschool children for refractive anomalies indicates definite usefulness and reasonable accuracy of the Retinomax for detecting myopia, astigmatism and hyperopia. The weak point of this screening technique is the diagnosis of anisometropia, with only moderate utility and poor accuracy.

Refraction as a basis for screening children for squint and amblyopia.

+2-00 to +2-75 dioptres of spherical hypermetropia in the more emmetropic of a pair of eyes is significantly associated with esotropia (P less than 0-001) and the presence of amblyopia (P less than 0-01). Anisometropia is not significantly associated with esotropia (P = 0-31) unless there is spherical hypermetropia of +2-00 dioptres or more in the more emmetropic eye (P less than 0-001). Hypermetropic anisometropia of +1-00 DS or +1-00 D.Cyl. is associated with the presence of amblyopia (P less than 0-001). In the absence of esotropia there is also a significant association between the amount of anisometropia and the initial depth of amblyopia (P less than 0-01). The additional presence of esotropia increases the depth of amblyopia further (P less than 0-05) but not the incidence of amblyopia (P greater than 0-30). The level of significance of the association of refractive errors with squint/amblyopia was itself significantly higher (P less than 0-01) than that between a family history of squint or "lazy eye" on the one hand and squint and/or amblyopia on the other hand. 72 +/- 3% of all cases of esotropia and/or amblyopia in this sample of children had a refractive error of +2-00 DS or more spherical hypermetropia in the more emmetropic eye, or +1-00 D. or more spherical or cylindrical anisometropia. Since there is a close association between the refraction and how, when, and whether a child presents with squint and/or amblyopia, it would seem reasonable to reconsider refraction as a basis for screening young children for visual defects.