Longitudinal refractive errors over 36 months in Hispanic and Black children.

SIGNIFICANCE: This study brings awareness of racial/ethnic difference of refractive error characteristics in clinics. PURPOSE: This study aimed to assess longitudinal change in refractive errors over a 36-month period in Hispanic and Black children. METHODS: Children (2.4 to 15 years old) were studied. Cycloplegic refraction was measured annually. Spherical equivalent was calculated. Astigmatism was evaluated by magnitude of cylinder and power vector (J 0 and J 45 ). Absolute value of interocular spherical equivalent difference was used to calculate anisometropia. Mixed-linear model was used to analyze longitudinal annual change in spherical equivalent, cylinder, J 0 , and J 45 over 36 months. RESULTS: A total of 485 participants (310 Black, 175 Hispanic) met the criteria. At the baseline examination, prevalence of myopia, emmetropia, and hyperopia was 39% (n = 187), 31% (n = 150), and 30% (n = 148), respectively. Spherical equivalent of Black children was not significantly different from that in Hispanic children (0.10 ± 2.92 vs. -0.37 ± 2.05 D, p=0.06); however, the Hispanic children had a significantly higher cylinder compared with Black children (Hispanic: 1.46 ± 1.57 D vs. Black: 0.92 ± 1.07 D; p<0.001). Both J 0 (p<0.001) and J 45 (p=0.01) were significantly different between two groups; the Hispanic children had more with-the-rule astigmatism and oblique astigmatism than the Black children. Prevalence of anisometropia (≥1 D) was higher in Black children (14%) compared with Hispanic children (5%, p=0.006). Over 36 months, spherical equivalent significantly decreased an average of 0.69 D (0.23 D/y, p<0.001) for both groups; neither astigmatism nor anisometropia changed significantly (p>0.05). CONCLUSIONS: Astigmatism in the Hispanic children was significantly higher than in Black children. However, the Black children had a higher prevalence and degree of anisometropia than the Hispanic children.

Refractive Error in Chinese Preschool Children: The Shanghai Study.

PURPOSE: To examine the prevalence of refractive error and some associated factors in Chinese preschool children. METHODS: The Jinshan District Eye Study was a school-based survey of eye health in a large sample of 4- to 6-year-olds attending kindergartens from May 2013 to December 2013 in Shanghai. Refractive error was measured using an autorefractor under noncycloplegic conditions. Axial length (AL) was measured with an ocular biometry system. In addition, body height and weight were also recorded. RESULTS: A total of 7,166 children successfully completed their refraction measurements. The median (interquartile range) of spherical equivalent (SE) for all the children was +0.25 D (-0.13 D to +0.62 D), and the range was -15.88 to +18.13 D. The mean AL for all the children was 22.35±0.70 mm, and the range was 18.20 to 27.71 mm. The overall prevalence of myopia (-1.00 D or less), hyperopia (+2.00 D or greater), and astigmatism (1.00 D or greater) were 5.9%, 1.0%, and 12.7%, respectively. After multivariate analysis, more myopic SE (or less hyperopic SE) was significantly associated with girls, longer AL, taller, and lighter. CONCLUSION: Shanghai has a high prevalence of refractive error in the world. However, longitudinal studies are needed to evaluate refractive changes over time in individual children and warranted to prevent the development of myopia.

[PREVALENCE OF ASTIGMATISM BEFORE ROUTINE CATARACT SURGERY: COMPARISON BETWEEN BEDOUIN AND JEWISH POPULATION IN SOUTHERN ISRAEL].

OBJECTIVES: To assess the prevalence of corneal astigmatism among patients before routine cataract surgery and overall ocular difference between Jewish and Bedouin population in the south of Israel. METHODS: Retrospective research collecting biometric information from IOLMaster (Carl Zeiss Meditec AG, Germany) in patients attending cataract surgery at Soroka University Medical Center, Beer-Sheva, Israel between the years 2015 -2016. RESULTS: Mean corneal astigmatism among all cohorts was 1.20D ± 0.83, with 1.26D ± 0.84 in Bedouins patients vs 1.17D ± 0.82 in Jews patients (p-value=0.08). Corneal astigmatism lower than 0.5D was seen in 20% of the population, 28% of the population had corneal astigmatism above 1.5D and 9% showed corneal astigmatism higher than 2.5D. When comparing axial length and keratometric characteristics between the two populations, Bedouins had shorter axial length (23.41mm± 1.62 vs. 23.67mm ± 1.55, p=0.01), and flatter corneas on both axes (flat - 43.18D ± 1.76 vs. 43.62D ± 1.79, p<0.01); (steep - 44.44D ± 1.84 vs. 44.77D± 1.89, p<0.01). Higher astigmatism was found in men than in women (1.24D vs.1.15D p- value=0.04) of study group. CONCLUSIONS: In our study we found more than 25% of patients had astigmatism more than 1.5D. Patients attending cataract surgery may therefore benefit the use of advanced IOL types and surgical techniques. In addition, a statistically significant difference between the Bedouin and Jewish populations biometric measurements in patients attending cataract surgery found.

A genome-wide association study of corneal astigmatism: The CREAM Consortium.

Purpose: To identify genes and genetic markers associated with corneal astigmatism. Methods: A meta-analysis of genome-wide association studies (GWASs) of corneal astigmatism undertaken for 14 European ancestry (n=22,250) and 8 Asian ancestry (n=9,120) cohorts was performed by the Consortium for Refractive Error and Myopia. Cases were defined as having >0.75 diopters of corneal astigmatism. Subsequent gene-based and gene-set analyses of the meta-analyzed results of European ancestry cohorts were performed using VEGAS2 and MAGMA software. Additionally, estimates of single nucleotide polymorphism (SNP)-based heritability for corneal and refractive astigmatism and the spherical equivalent were calculated for Europeans using LD score regression. Results: The meta-analysis of all cohorts identified a genome-wide significant locus near the platelet-derived growth factor receptor alpha (PDGFRA) gene: top SNP: rs7673984, odds ratio=1.12 (95% CI:1.08-1.16), p=5.55×10-9. No other genome-wide significant loci were identified in the combined analysis or European/Asian ancestry-specific analyses. Gene-based analysis identified three novel candidate genes for corneal astigmatism in Europeans-claudin-7 (CLDN7), acid phosphatase 2, lysosomal (ACP2), and TNF alpha-induced protein 8 like 3 (TNFAIP8L3). Conclusions: In addition to replicating a previously identified genome-wide significant locus for corneal astigmatism near the PDGFRA gene, gene-based analysis identified three novel candidate genes, CLDN7, ACP2, and TNFAIP8L3, that warrant further investigation to understand their role in the pathogenesis of corneal astigmatism. The much lower number of genetic variants and genes demonstrating an association with corneal astigmatism compared to published spherical equivalent GWAS analyses suggest a greater influence of rare genetic variants, non-additive genetic effects, or environmental factors in the development of astigmatism.

Management of epiblepharon: state of the art.

PURPOSE OF REVIEW: Epiblepharon is prevalent in East-Asian children. As the population in Asia is increasing, so is the demand for epiblepharon surgery. Surgeons should be familiar with the standards of beauty and needs of Asian people for epiblepharon management. This review provides a comprehensive summary of the published studies on the clinical manifestations, pathophysiology, and management of epiblepharon. RECENT FINDINGS: Astigmatism is prevalent in epiblepharon patients, which can contribute to amblyopia. Early surgery and visual rehabilitation is important for epiblepharon patients with a high degree of astigmatism and amblyopia. Various etiologic factors play a role in the pathophysiology of epiblepharon. Surgical procedures focusing on creation of a lower eyelid crease have been popular for treating epiblepharon in Western textbooks; however, this is not appropriate for Asian patients in whom, a crease may be undesirable. In selecting surgical methods, it is important to resect a minimal amount of skin-muscle to avoid the adverse effects of ectropion and eyelid retraction. SUMMARY: Although epiblepharon may resolve with facial growth, surgical correction is needed for cases in which there is significant corneal injury from the lash touch. Surgical management should focus on techniques that are effective, with little chance of complication, and do not create a lower eyelid crease.

Internal Astigmatism in Myopes and Non-myopes: Compensation or Constant?

PURPOSE: To examine internal astigmatism (IA) in myopes and non-myopes using a new method to assess compensation of corneal astigmatism (CA) by IA, to look for predictors of high IA in young adult myopes, and to determine if as CA changes IA changes to reduce refractive astigmatism (RA) in an active compensatory process in myopes. METHODS: Right eye keratometry and cycloplegic autorefraction were measured annually over 14 years in 367 myopes and once in 204 non-myopes age- (mean 21.91 ± 1.47 years), gender-, and ethnicity-matched to myopes at year 12. CA and RA at the corneal plane were expressed as J0, J45. IA = RA - CA. Inverse power transformation provided cylinder power and axis of IA for the compensation factor (IA/CA). Analyses included (1) paired and unpaired t-tests (refractive data), (2) chi-square tests (distributions of compensation factor), (3) logistic regression analysis (predictors of high IA), and (4) linear mixed models (time effect on RA, CA, and IA). RESULTS: The magnitude of IAJ0 varied by refractive error (myopes -0.25 ± 0.24 vs. non-myopes -0.32 ± 0.21, p < 0.001). Compensation of CA by IA was poorer in myopes than non-myopes (χ p < 0.001). When matched by CA, compensation remained poorer in myopes than non-myopes (χ all p ≤ 0.04). Within each refractive group, compensation was better when CA was low than high (χ p < 0.001). When CA was low in myopes, high IA (≥1.00D) was less likely (p = 0.01). Longitudinal follow-up of myopes found no evidence for an active compensatory role for IA as CA increased over time. There were differences in IAJ0 by ethnicity over time (p < 0.0001). CONCLUSIONS: In myopic and non-myopic eyes with low amounts of CA, IA may reduce CA's contribution to RA, but IA is not a constant. However, there is no evidence for an active compensatory role for IA reducing CA in myopes.

Profile of refractive errors in European Caucasian children with Autistic Spectrum Disorder; increased prevalence and magnitude of astigmatism.

PURPOSE: Autistic Spectrum Disorder (ASD) is a common neurodevelopmental disorder characterised by impairment of communication, social interaction and repetitive behaviours. Only a small number of studies have investigated fundamental clinical measures of vision including refractive error. The aim of this study was to describe the refractive profile of a population of children with ASD compared to typically developing (TD) children. METHODS: Refractive error was assessed using the Shin-Nippon NVision-K 5001 open-field autorefractor following the instillation of cyclopentolate hydrochloride 1% eye drops. RESULTS: A total of 128 participants with ASD (mean age 10.9 ± 3.3 years) and 206 typically developing participants (11.5 ± 3.1 years) were recruited. There was no significant difference in median refractive error, either by spherical equivalent or most ametropic meridian between the ASD and TD groups (Spherical equivalent, Mann-Whitney U307 = 1.15, p = 0.25; Most Ametropic Meridian, U305 = 0.52, p = 0.60). Median refractive astigmatism was -0.50DC (range 0.00 to -3.50DC) for the ASD group and -0.50DC (Range 0.00 to -2.25DC) for the TD group. Magnitude and prevalence of refractive astigmatism (defined as astigmatism ≥1.00DC) was significantly greater in the ASD group compared to the typically developing group (ASD 26%, TD 8%, magnitude U305 = 3.86, p = 0.0001; prevalence (χ12=17.71 , p < 0.0001). CONCLUSIONS: This is the first study to describe the refractive profile of a population of European Caucasian children with ASD compared to a TD population of children. Unlike other neurodevelopmental conditions, there was no increased prevalence of spherical refractive errors in ASD but astigmatic errors were significantly greater in magnitude and prevalence. This highlights the need to examine refractive errors in this population.

Ocular Aberrations and Corneal Shape in Adults with and without Astigmatism.

PURPOSE: To characterize and compare the corneal shapes and monochromatic aberrations in Chinese myopic adults with and without astigmatism. METHODS: Forty-six Hong Kong Chinese aged 50 to 70 years with compound against-the-rule myopic astigmatism (n = 18) or simple myopia (n = 28) were recruited. Corneal shapes were measured by a Scheimpflug-based corneal topographer: the semimeridian corneal shape factors at the nasal, temporal, inferior, and superior corneal quadrants measured from the corneal apex to 3 mm midperiphery were analyzed. The ocular aberrations were measured by the COAS (Complete Ophthalmic Analysis System) Shack-Hartmann wavefront aberrometer; the corneal aberrations were computed using the corneal topographic map data measured by the Medmont E300 corneal topographer; and the internal aberrations were calculated from the ocular and corneal aberrations. RESULTS: Compared with simple myopia, myopic astigmatism had more oblate nasal and temporal corneal shapes and showed significantly more negative Y trefoil and more positive vertical coma. The asymmetry in corneal shape along the vertical principal meridian (inferior - superior) was significantly associated with the Y trefoil and vertical coma of the cornea, suggesting that this regional asymmetry in corneal shape may contribute to the ocular aberrations. CONCLUSIONS: The significant relationships found between astigmatism, corneal shapes, and monochromatic aberrations underscore the importance of taking corneal shape into account when correcting the optical defects in myopic Chinese adults with astigmatism.

Refractive status of Chinese with laser-treated retinopathy of prematurity.

PURPOSE: To analyze changes in myopia, astigmatism, and anisometropia after laser treatment of retinopathy of prematurity (ROP), including aggressive posterior retinopathy of prematurity (APROP), in Mainland Chinese children. METHODS: This was a retrospective study of children who had laser treatment for threshold or type 1 prethreshold ROP between January 2004 and October 2012 and age-matched control subjects with spontaneously regressed type 2 prethreshold ROP. One hundred fifteen eyes of 60 patients were included as the laser-treated group, which were further subdivided into APROP and non-APROP groups. Thirty-seven eyes of 20 patients who were diagnosed during the same period were included as the control group. Between 12 and 36 months postnatal age (PA) (mean [±SD], 22.9 [±8.1] months), cycloplegic retinoscopy was performed to measure refractive outcomes. A general linear model was used to analyze refractive changes among different groups at each PA. RESULTS: After adjusting for PA and the correlation between right and left eyes, the magnitude and proportion of astigmatism (p = 0.04 and p = 0.004, respectively) and myopia (p < 0.0001 and p = 0.006, respectively) were greater in the laser-treated group than in the control group. The differences in myopia were even greater in children with APROP than those with non-APROP, whereas the differences in astigmatism were not. Eyes with APROP had higher prevalence of high myopia and spherical anisometropia than the control (p = 0.002 and p = 0.02, respectively) and the non-APROP groups (p < 0.0001 and p = 0.04, respectively). CONCLUSIONS: Children with laser treatment for ROP, including APROP, tended to have higher myopia, astigmatism, and anisometropia, which may progress to amblyopia. These findings highlight the need for regular refractive screening after laser treatment of ROP.

Risk factors for astigmatism in the Vision in Preschoolers Study.

PURPOSE: To determine demographic and refractive risk factors for astigmatism in the Vision in Preschoolers Study. METHODS: Three- to 5-year-old Head Start preschoolers (N = 4040) from five clinical centers underwent comprehensive eye examinations by study-certified optometrists and ophthalmologists, including monocular visual acuity testing, cover testing, and cycloplegic retinoscopy. Astigmatism was defined as the presence of greater than or equal to +1.5 diopters (D) cylinder in either eye, measured with cycloplegic refraction. The associations of risk factors with astigmatism were evaluated using the odds ratio (OR) and its 95% confidence interval (CI) from logistic regression models. RESULTS: Among 4040 Vision in Preschoolers Study participants overrepresenting children with vision disorders, 687 (17%) had astigmatism, and most (83.8%) had with-the-rule astigmatism. In multivariate analyses, African American (OR, 1.65; 95% CI, 1.22 to 2.24), Hispanic (OR, 2.25; 95% CI, 1.62 to 3.12), and Asian (OR, 1.76; 95% CI, 1.06 to 2.93) children were more likely to have astigmatism than non-Hispanic white children, whereas American Indian children were less likely to have astigmatism than Hispanic, African American, and Asian children (p < 0.0001). Refractive error was associated with astigmatism in a nonlinear manner, with an OR of 4.50 (95% CI, 3.00 to 6.76) for myopia (≤-1.0 D in spherical equivalent) and 1.55 (95% CI, 1.29 to 1.86) for hyperopia (≥+2.0 D) when compared with children without refractive error (>-1.0 D, <+2.0 D). There was a trend of an increasing percentage of astigmatism among older children (linear trend p = 0.06). The analysis for risk factors of with-the-rule astigmatism provided similar results. CONCLUSIONS: Among Head Start preschoolers, Hispanic, African American, and Asian race as well as myopic and hyperopic refractive error were associated with an increased risk of astigmatism, consistent with findings from the population-based Multi-ethnic Pediatric Eye Disease Study and the Baltimore Pediatric Eye Disease Study. American Indian children had lower risk of astigmatism.

Prevalence of myopia, hyperopia, and astigmatism in non-Hispanic white and Asian children: multi-ethnic pediatric eye disease study.

PURPOSE: To determine the age-, gender-, and ethnicity-specific prevalence of myopia, hyperopia, and astigmatism in non-Hispanic white (NHW) and Asian preschool children. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A population-based sample of 1501 NHW children and 1507 Asian children aged 6-72 months from Los Angeles County and Riverside County, California. METHODS: Eligible children underwent an in-home and in-clinic interview and a comprehensive eye examination including cycloplegic autorefraction from 100 census tracts. MAIN OUTCOME MEASURES: The proportion of children with myopia (spherical equivalent [SE] ≤-1.00 diopter [D]), hyperopia (SE ≥ +2.00 D) and cylindrical refractive error ≥1.50 D in the worse eye. The astigmatism type was defined as with-the-rule (WTR; +cylinder axis 90°±15°) and against-the-rule (ATR; + cylinder axis 180°±15°); all other orientations were considered oblique (OBL). RESULTS: The prevalence of myopia, hyperopia, and astigmatism in NHW children was 1.20% (95% confidence interval [CI], 0.76%-1.89%), 25.65% (95% CI, 23.5%-27.9%), and 6.33% (95% CI, 5.21%-7.68%), respectively. The prevalence of WTR, ATR, and OBL astigmatism in NHW children was 4.33%, 1.00%, and 1.00%, respectively. Prevalence was lower with older age groups for astigmatism (P = 0.0002), but not for myopia (P = 0.82) or hyperopia (P = 0.31). In Asian children, the prevalence of myopia, hyperopia, and astigmatism was 3.98% (95% CI, 3.11%-5.09%), 13.47% (95% CI, 11.8%-15.3%), and 8.29% (95% CI, 7.01%-9.80%), respectively. The prevalence of WTR, ATR, and OBL astigmatism was 6.50%, 0.80%, and 1.00% respectively. The prevalence of hyperopia was higher in girls than boys (P = 0.0002), but no differences were found for myopia and astigmatism. CONCLUSIONS: Hyperopia was the most common refractive error in both Asian and NHW children. However, compared with NHW children, myopia was relatively more prevalent, and hyperopia less prevalent, among Asian children. The prevalence of astigmatism was greatest in infants, and WTR astigmatism predominated at all ages. Myopia showed relatively stable prevalence across age groups, whereas hyperopia prevalence decreased after infancy and then increased again in older age groups; however, longitudinal studies are needed to evaluate refractive changes over time in individual children. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Corneal shapes of Chinese emmetropes and myopic astigmats aged 10 to 45 years.

PURPOSE: Myopia and astigmatism are highly prevalent in the Hong Kong Chinese. This study aimed to determine the effects of age and myopic astigmatism (MA) on the corneal shape factors in the Hong Kong Chinese. METHODS: One hundred subjects with compound MA or emmetropia (EM) were recruited from three age groups: 10 to 15 years (n = 32), 20 to 25 years (n = 37), and 40 to 45 years (n = 31). Refractive errors were measured by noncycloplegic subjective refraction. Corneal astigmatism and corneal shape factors were measured by the Scheimpflug-based Pentacam. The effects of age and refractive errors on the whole corneal shape (mean-P) and the semimeridian corneal shapes (semi-Ps) at the nasal, temporal, superior, and inferior corneal quadrants (from corneal apex to 3 mm peripheral cornea) were analyzed. RESULTS: Age had significant effects on the mean-P and semi-Ps (both p < 0.001), with both EM and MA showing less prolate corneal shapes in older age groups. Partial correlation analyses adjusted for age showed that mean-P and semi-Ps were correlated with multiple refractive-error components (Pearson r = -0.30 to -0.78, all p < 0.05), with higher correlations found along the horizontal semi-Ps in MA (Pearson r = +0.37 to -0.78, all p < 0.01). Compared with EM, MA had more prolate temporal semi-Ps in all the three age groups (p < 0.05). Strikingly, age and refractive errors also had significant impacts on the asymmetry of the corneal shape along the horizontal meridian. CONCLUSIONS: Corneal shapes were influenced by age and MA in the Hong Kong Chinese. These results highlight the importance of controlling these factors when designing a study on corneal shape.

Astigmatism and myopia in Tohono O'odham Native American children.

PURPOSE: To describe change in spherical equivalent (M) in a longitudinal sample of Tohono O'odham students ages 3 to 18 years and to test the hypothesis that astigmatism creates complex cues to emmetropization, resulting in increased change in M in the direction of increasing myopia and increased occurrence of myopia. METHODS: Subjects were 777 Tohono O'odham Native American children on whom cycloplegic right eye autorefraction was measured on at least two study encounters between ages 3 and 18 years (first encounter prior to age 5.5 years, final encounter ≥3 years later). Regression lines were fit to individual subjects' longitudinal M data to estimate rate of change in M (regression slope, D/yr). Regression was also used to predict if a subject would be myopic (≤-0.75 D M) by age 18 years. Analysis of covariance was used to assess the relation between M slope and magnitude of baseline M and astigmatism. Chi-square analyses were used to assess the relation between predicted myopia onset and magnitude of baseline M and astigmatism. RESULTS: Mean M slope was significantly more negative for hyperopes (M ≥ +2.00) than for myopes (M ≤ -0.75) or for subjects neither hyperopic nor myopic (NHM, M > -0.75 and < +2.00), but there was no significant difference between the myopic and NHM groups. Chi-square analysis indicated that final myopia status varied across level of baseline astigmatism. Subjects with high astigmatism were more likely to be predicted to have significant myopia by age 18 years. CONCLUSIONS: The association between greater shift in M towards myopia with age in subjects who were hyperopic at baseline is consistent with continued emmetropization in the school years. Results regarding predicted myopia development imply that degradation of image quality due to refractive astigmatism creates complex cues to emmetropization, resulting in increased occurrence of myopia.

Refractive error and visual function difficulty in a Latino population.

OBJECTIVE: To assess the association of correction of myopia, hyperopia, and astigmatism with self-reported near and distance visual function. DESIGN: Population based, cross-sectional study. PARTICIPANTS: A random sample of 4272 Latinos older than 40 years of age from Arizona with both ophthalmic examination and questionnaire data, including answers to the National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ-25). METHODS: Cases of refractive error (RE) were defined as subjects who met at least 1 of the following criteria in both eyes: myopia, sphere -0.5 diopters (D) or less; hyperopia, sphere 1.0 D or more; or astigmatism, cylinder 0.75 D or more. Uncorrected refractive error (URE) was defined as having RE and achieving 2 lines or more of improvement in visual acuity in both eyes after refraction. The association between RE category and near and distance vision difficulty (as measured by the NEI VFQ-25 near and distance vision subscores) was modeled with ordinal logistic regression, adjusting for age, gender, diabetes, hypertension, income, education, and acculturation. MAIN OUTCOME MEASURES: Association between RE correction and near and distance vision difficulty by type of RE (myopia, hyperopia, and astigmatism). RESULTS: Of 4272 participants, 54% had RE. Forty-eight percent of these had myopia, 41% had hyperopia, and 11% had astigmatism. Fourteen percent of myopes, 21% of hyperopes, and 22% of astigmatics had URE. Subjects with myopia, astigmatism, and hyperopia were significantly more likely to report more distance vision difficulty than subjects without RE, regardless of whether they had correction (odds ratios [ORs], 1.7-3.7; P<0.005 for all). Subjects with corrected myopia reported less near vision difficulty than subjects without RE (OR, 0.8; 95% confidence interval [CI], 0.7-0.9). Subjects with uncorrected hyperopia and uncorrected astigmatism reported more near vision difficulty than those without RE (OR, 1.6; 95% CI, 1.2-2.2; and OR, 1.7; 95% CI, 1.0-3.0, respectively). Self-reported distance and near visual function scores were sensitive to nonvision variables, namely, age, gender, diabetes, high blood pressure, acculturation score, income, and education. CONCLUSIONS: In this population, correction of any type of RE is not entirely sufficient to restore distance visual function to the level of those without RE. More research is necessary to determine the reasons for this shortcoming.

Prevalence of astigmatism in 6- to 72-month-old African American and Hispanic children: the Multi-ethnic Pediatric Eye Disease Study.

PURPOSE: To determine the age-, gender-, and ethnicity-specific prevalence of astigmatism in African American and Hispanic children aged 6 to 72 months. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: The Multi-Ethnic Pediatric Eye Disease Study is a population-based evaluation of the prevalence of vision disorders in children ages 6 to 72 months in Los Angeles County, California. Seventy-seven percent of eligible children completed a comprehensive eye examination. This report provides the results from 2994 African American and 3030 Hispanic children. METHODS: Eligible children in 44 census tracts were identified during an in-home interview and scheduled for a comprehensive eye examination and in-clinic interview. Cycloplegic autorefraction was used to determine refractive error. MAIN OUTCOME MEASURES: The proportion of children with astigmatism defined as cylindrical refractive error ≥ 1.50 diopters (D) in the worse eye. The astigmatism type was defined as with-the-rule (WTR) (+ cylinder axis 90 ± 15 degrees) and against-the-rule (ATR) (+ cylinder axis 180 ± 15 degrees); all other orientations were considered oblique (OBL). The prevalence of astigmatism and its types were also determined for worse eye cylindrical refractive error ≥ 3.00 D. RESULTS: Prevalence of astigmatism ≥ 1.50 D was higher in Hispanic children compared with African American children (16.8% vs. 12.7%, respectively; P<0.0001). Hispanic children also showed a higher prevalence of astigmatism ≥ 3.00 D than African American children (2.9% vs. 1.0% respectively; P<0.0001). The prevalence of astigmatism ≥ 1.50 D showed a significant decreasing trend with age (P<0.0001). The prevalence of WTR, ATR, and OBL astigmatism ≥ 1.50 D was 13.9%, 0.6%, and 2.2%, respectively, in Hispanic children, and 7.8%, 2.2%, and 2.7%, respectively, in African American children. CONCLUSIONS: We observed ethnicity-related differences in astigmatism prevalence in preschool children. The age-related decrease in astigmatism prevalence in preschool children likely reflects emmetropization.

Risk factors for astigmatism in preschool children: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies.

OBJECTIVE: To evaluate risk factors for astigmatism in a population-based sample of preschool children. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Population-based samples of 9970 children ages 6 to 72 months from Los Angeles County, California, and Baltimore, Maryland. METHODS: A cross-sectional study of children participating in the Multiethnic Pediatric Eye Disease Study and the Baltimore Eye Disease Study was completed. Data were obtained by clinical examination or by in-person interview. Odds ratios and 95% confidence intervals (CI) were calculated to evaluate potential associations between clinical, behavioral, or demographic factors and astigmatism. MAIN OUTCOME MEASURES: Odds ratios (ORs) for various risk factors associated with astigmatism. RESULTS: Participants with myopia (≤-1.0 diopters) were 4.6 times as likely to have astigmatism (95% CI, 3.56-5.96) than those without refractive error, whereas participants with hyperopia (≥+2.00 diopters) were 1.6 times as likely (95% CI, 1.39-1.94). Children 6 to <12 months of age were approximately 3 times as likely to have astigmatism than children 5 to 6 years of age (95% CI, 2.28-3.73). Both Hispanic (OR, 2.38) and African-American (OR, 1.47) children were as likely to have astigmatism than non-Hispanic white children. Furthermore, children whose mothers smoked during pregnancy were 1.46 times (95% CI, 1.14-1.87) as likely to have astigmatism than children whose mothers did not smoke. CONCLUSIONS: In addition to infancy, Hispanic and African-American race/ethnicity and correctable/modifiable risk factors such as myopia, hyperopia, and maternal smoking during pregnancy are associated with a higher risk of having astigmatism. Although the prevalence of smoking during pregnancy is typically low, this association may suggest etiologic pathways for future investigation. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Optical treatment reduces amblyopia in astigmatic children who receive spectacles before kindergarten.

OBJECTIVE: To examine the effect of spectacle correction of astigmatism during preschool on best-corrected recognition visual acuity (VA), grating VA, and meridional amblyopia (difference between acuity for vertical versus horizontal gratings) once the children reach kindergarten. DESIGN: Comparative case series. PARTICIPANTS: Seventy-three astigmatic (right eye > or =1.50 diopters [D] cylinder) Native American (Tohono O'odham) children 5 to 7 years of age. All had with-the-rule astigmatism. In 28 children, the astigmatism was simple myopic, compound myopic, or mixed (M/MA), and in 45 children, it was simple or compound hyperopic (HA). INTERVENTION: Thirty-nine children (Treated Group) had spectacle correction of refractive error, prescribed for full-time wear, in preschool (0.8-2.4 years before testing). Thirty-four children (Untreated Group) had no prior correction. MAIN OUTCOME MEASURE: Comparison of Treated versus Untreated Groups for mean best-corrected right-eye recognition VA, measured with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart and the Lea Symbols chart, for grating VA, measured with modified Teller acuity card stimuli, and for meridional amblyopia, based on grating acuity results. RESULTS: Mean ETDRS VA was significantly better in the Treated Group (20/37) than in the Untreated Group (20/48; P<0.003), but the difference between mean Lea Symbols VA in the Treated Group (20/33) and in the Untreated Group (20/38) was not significant. No significant Treated versus Untreated Group differences were found for either vertical or horizontal grating acuity. Meridional amblyopia differed between the M/MA group, which showed better acuity for vertical than for horizontal gratings, and the HA group, which showed better acuity for horizontal than for vertical gratings. However, in neither the M/MA group nor the HA group was there a significant difference in magnitude of meridional amblyopia in the Treated versus the Untreated Group. CONCLUSIONS: Spectacle correction during the preschool years results in a significant improvement in best-corrected letter recognition acuity in astigmatic children by the time they reach kindergarten. However, grating acuity was not improved and magnitude of meridional amblyopia was not reduced in children who had received early spectacle correction. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Preschool Children Exhibit Evident Compensatory Role of Internal Astigmatism in Distribution of Astigmatism: The Nanjing Eye Study.

Purpose: To determine the prevalence and associated risk factors for total, corneal, and residual astigmatism and to evaluate the relations between components of astigmatism in Chinese preschool children. Methods: In the population-based, cross-sectional Nanjing Eye Study, children were measured for noncycloplegic refractive error using an autorefractor and for biometric parameters using an optical low-coherent reflectometry. Data from right eyes were analyzed to calculate the prevalence of astigmatism using various cutpoints (0.5, 1.0, and 1.5 diopters [D]) and for determining risk factors using logistic regression models. Relations between astigmatism components were assessed using Spearman correlation coefficients (ρ). Results: Of 1817 children (mean ± SD of age: 54.8 ± 3.5 months, 54.2% male), the median (1st and 3rd quartile) of total, corneal, and residual astigmatism (vectorial difference between total and corneal astigmatism) was -0.25 (-0.50, 0), -1.06 (-1.49, -0.72), and -0.92 (-1.23, -0.62) D and their prevalence rate 1.0 D or more was 14.2%, 56.1%, and 44.2%, respectively. With-the-rule was the most common type in total astigmatism (75.2%) and in corneal astigmatism (88.2%) while against-the-rule was predominant in residual astigmatism (75.6%). A negative correlation was found between corneal J0 and internal J0 (ρ = -0.74, P < 0.001) and between corneal J45 and internal J45 (ρ = -0.87, P < 0.001). Based on compensation factor (CF), defined as the minus ratio of internal astigmatism (vectorial difference between total and anterior corneal astigmatism) and anterior corneal astigmatism, internal J0 compensated for total J0 in varying degrees (CF: 0.1-2) in 91.5% cases, while that percentage for J45 component was 77.2%. In univariate logistic regression model, older age was significantly associated with total astigmatism (odds ratio [OR] = 0.96 for per-month increase, P = 0.03), and larger axial length-corneal radius ratio was significantly associated with higher risk of residual astigmatism (OR = 2.28 for per unit increase, P = 0.03). Conclusions: The compensatory role of internal astigmatism on reducing corneal astigmatism was prominent in preschool children. Larger axial length-corneal radius ratio was significantly associated with higher risk of residual astigmatism.

Iris colour and astigmatism among Chinese teenagers.

BACKGROUND/AIMS: Iris colour might contribute to refractive development, but it is uncertain whether it is related to astigmatism. We aim to examine the association of iris colour with the presence of astigmatism in a school-based sample of Chinese students. METHODS: 2346 grade 7 students from 10 middle schools aged 13 to 14 years in Southwestern China participated in the study. We obtained standardised slit-lamp photographs and developed a grading system assessing iris colour (higher grade denoting darker). Astigmatism was defined as a cylinder power of more than 0.50, 0.75 or 1.00 dioptre (D). Logistic regression models with generalised estimating equation were fitted to assess the relationship between iris colour and astigmatism, accounting for the correlation between both eyes. ORs and 95% CIs were presented. RESULTS: The overall prevalence of astigmatism for three different definitions was 30.4% (95% CI 28.6% to 32.2%) (<-0.5 D), 12.7 % (95% CI 11.3% to 14.0%) (<-0.75 D) and 5.3% (95% CI 4.4% to 6.2%) (<-1.0 D), respectively. In multivariate analysis adjusting for the effect of gender and height, darker iris colour was associated with an increasing trend of astigmatism (p for trend <0.05). Compared with individuals with iris colour of grade 4 or 5 (the darkest), those with grade 1 or 2 (the lightest) were significantly less likely to be affected by astigmatism (<-0.75 D) in gender-adjusted model (OR 0.67) and multivariate-adjusted model (OR 0.72). CONCLUSION: Darker iris colour might be a risk factor for astigmatism in Chinese adolescents.

Higher-order aberrations in young refractive surgery candidates in India: establishment of normal values and comparison with white and Chinese Asian populations.

PURPOSE: To establish normal values of higher-order aberrations (HOAs) in young candidates in an Indian population and compare them with results in white and Asian (Chinese) populations. SETTING: Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. METHODS: This prospective trial comprised 206 consecutive candidates (412 eyes) for customized laser in situ keratomileusis. Exclusion criteria were previous ocular surgery, corneal ectasia, rigid gas-permeable contact lens use, corneal scar, or cataract. Higher-order aberrations were analyzed on a Zywave workstation (Bausch & Lomb Surgical). RESULTS: The mean age was 23.63 years +/- 1.99 (SD); the mean refractive error, -2.97 +/- 4.0 diopters (D) sphere and -1.73 +/- 3.6 D cylinder; and the mean 6.0 mm HOA root mean square (RMS), 0.36 +/- 0.26 microm. The most predominant HOAs were 3rd order (coma, trefoil). The summated RMS of the 3rd order was the most predominant (mean 0.23 +/- 0.15 microm), followed by the 4th and 5th orders (P<.0001). The ratio between summated RMS means was 1:0.7:0.3, similar to that in white populations (1:0.7:0.3) and different than in Asian (Chinese) populations (1: ~ 0.8:0.002). Third- and 4th-order aberrations were between 60% and 70% higher in Asian (Chinese) eyes. The difference between data in this study and those in others was less than 10% in 3rd and 4th order. CONCLUSION: The normative data for HOA in Indian eyes closely matched that in white populations but was different from that in Asian (Chinese) populations, which may provide help in nomogram modifications.