Prevalence and risk factors of myopia in Han and Yugur older adults in Gansu, China: a cross-sectional study.

Few studies have investigated the prevalence of myopia in Northwest China. This cross-sectional study aimed to investigate the prevalence and associated factors of myopia and high myopia in adults aged 40-80 years in the Han and Yugur populations living in Gansu Province, Northwest China. A total of 3,845 participants were included. The overall age- and sex-adjusted prevalence of myopia (spherical equivalent (SE) < -0.5 D), high myopia (SE < -6.0 D) and hyperopia (SE > + 0.5 D) were 16.4%, 0.7% and 26.2% in Yugur participants, respectively, and 34.3%, 5.0% and 19.2% in Han participants, respectively. The prevalence of myopia and high myopia in Han participants was significantly higher than that in Yugur participants (both P < 0.001). Yugur population, birth in rural areas, smoking history and outdoor work were found to be negatively associated with myopia. Higher education level and a family history of myopia were found to be positively associated with myopia in the study population. High myopia was negatively associated with Yugur population, aging, birth in rural areas and was positively associated with a family history of myopia. This study provided valuable information regarding the environmental risk factors of myopia and revealed an ethnic disparity in the prevalence of myopia in Gansu Province, Northwest China.

Clinical characteristics of congenital lamellar cataract and myopia in a Chinese family.

To investigate the clinical characteristics and the genetic defect in a Chinese family with congenital lamellar cataract with myopia. Three generations of a single family were recruited in the present study. A detailed family history and clinical data were recorded. A total of 100 unrelated ethnically matched controls without family history of congenital cataracts and myopia were also recruited. Genomic DNA was extracted from peripheral blood leukocytes. The sequencing of candidate genes was performed to screen out the disease-causing mutation. The effects of amino acid changes on the structure of proteins were predicted by bioinformatics analysis. Affected individuals presented lamellar lens opacities and myopia. Direct sequencing revealed a heterozygous c. 34 C>T variation in the αA-crystallin protein (CRYAA) gene, which resulted in the replacement of a highly conserved arginine by cystine at codon 12 (p.R12C). This mutation co-segregated with all affected individuals and was not observed in unaffected members or the 100 normal controls. Bioinformatic analysis showed that a highly conserved region was located around Arg12, an increase in local hydrophobicity was shown around the substitution site and the secondary structure of the mutant CRYAA protein has been changed. This is the case of a congenital lamellar cataract phenotype with myopia associated with the mutation of Arg12Cys (p.R12C) in CRYAA. Our finding confirms the high rate of mutations at this dinucleotide. In addition, these results demonstrate a myopia susceptibility locus in this region, which might also be associated with the mutation in CRYAA.

Early Diagnosis of Keratoconus in Chinese Myopic Eyes by Combining Corvis ST with Pentacam.

Purpose: This study was designed to evaluate and compare the sensitivity and specificity of the Belin/Ambrósio Deviation (BADD), Corneal Biomechanical Index (CBI) and Tomographic and Biomechanical Index (TBI) for the diagnosis of keratoconus in Chinese myopic eyes prior to undergoing corneal refractive surgery.Methods: A total of 125 patients (185 eyes) planned to undergo corneal refractive surgery were selected from the Refractive Center of Beijing Tongren Hospital between December 2017 and December 2018. They were divided into four groups: the normal group, bilateral keratoconus (BK) group, unilateral keratoconus (UK) group, and the forme fruste keratoconus (FFK) group. After determining the BADD, CBI, and TBI for each eye using the Corvis ST combined with Pentacam, the sensitivity and specificity of these three indices in diagnosing keratoconus were analyzed through receiver operating characteristic (ROC) curves.Results: The TBI exhibited the highest diagnostic efficiency in normal vs. UK (area under the ROC curve [AUROC]: 0.992), normal vs. UK+BK (AUROC: 0.988), normal vs. UK+BK* (*stand randomly selecting one eye of each patient in BK group) (AUROC: 0.982), normal vs. UK+BK+FFK (AUROC: 0.965), and normal vs. UK+BK*+FFK (AUROC: 0.953). The CBI demonstrated the highest diagnostic efficiency in normal vs. FFK (AUROC: 0.897). Finally, the BADD showed the highest diagnostic efficiency in normal vs. BK (AUROC: 0.998) and normal vs. BK* (AUROC: 0.996).Conclusion: The BADD, CBI, and TBI performed well in diagnosing keratoconus in Chinese myopic eyes. The CBI showed the highest diagnostic efficiency compared with normal for FFK. In addition, the TBI offered the greatest accuracy in detecting keratoconus and FFK eyes vs. the other parameters.

Comparison of intraocular lens power calculation formulas in Chinese eyes with axial myopia.

PURPOSE: To assess the accuracy of intraocular lens (IOL) power calculation formulas in Chinese eyes with axial lengths (ALs) longer than 26.0 mm. SETTING: Department of Cataract Surgery, Shanxi Eye Hospital, China. DESIGN: Prospective case series. METHODS: This study evaluated (1) two new formulas (Barrett Universal II and Hill-RBF 2.0), (2) three vergence formulas (Haigis, Holladay 1, and SRK/T), and (3) the original and modified Wang-Koch AL adjustment formulas with Holladay 1 and SRK/T. The User Group for Laser Interference Biometry lens constants were used for IOL power calculation. The refractive prediction error was calculated by subtracting the predicted refraction from the actual refraction postoperatively. The mean numerical error (MNE), percentage of eyes with hyperopic outcomes, and mean absolute error (MAE) were determined. RESULTS: The study comprised 136 eyes. The Barrett and Hill-RBF formulas had MNEs close to zero (-0.09 D to 0.03 D), the Haigis, Holladay 1, and SRK/T produced hyperopic MNEs (0.25 to 0.70 D), and the original and modified Wang-Koch AL adjustment formulas induced myopic MNEs (-0.48 to -0.22 D). The original Wang-Koch formulas produced significantly lower percentages of eyes with hyperopic outcomes (15% to 18%) than all other formulas (28% to 91%). There were no significant differences in MAEs between the Barrett, Hill-RBF, Haigis, and original and modified Wang-Koch adjustment with the Holladay 1 (0.32 to 0.41 D). CONCLUSION: The performances of the Barrett and Hill-RBF were comparable in long eyes. The incidence of hyperopic outcome with the Wang-Koch AL adjustment formula was significantly lower than other formulas.

PEDIATRIC RETINAL DETACHMENT IN AN ASIAN POPULATION WITH HIGH PREVALENCE OF MYOPIA: Clinical Characteristics, Surgical Outcomes, and Prognostic Factors.

PURPOSE: To evaluate the clinical characteristics and surgical outcomes of pediatric retinal detachments (RDs) in an Asian population. METHODS: Retrospective review of 171 eyes of 152 pediatric patients with rhegmatogenous RD over a 20-year period. RESULTS: Myopia was the most common risk factor in our population. At 6 months, primary anatomical success was 60.7%, and overall anatomical success was 86.7%. A total of 46.8% had best-corrected visual acuity of 20/40 or better, and 81.6% had best-corrected visual acuity of 20/200 or better. In primary RDs, high myopia (≤-6D) patients had a lower primary anatomical success compared to patients with moderate myopia (≤-2D) (59.3 vs. 100% P = 0.03). Increasing age and absence of proliferative vitreoretinopathy were associated with anatomical and visual success. Pars plana vitrectomy as the primary procedure was associated with decreased odds of anatomical success. A longer duration of symptoms, cataract, and a larger RD extent were associated with poorer functional outcome. CONCLUSION: Myopia was the commonest risk factor for pediatric RD in our population. Good anatomical and functional outcome can be achieved with surgery. Increasing age at presentation and absence of proliferative vitreoretinopathy was associated with anatomical and functional success. High myopia was associated with poorer anatomical and functional outcome.

Myopia in Chinese families shows linkage to 10q26.13.

Purpose: To determine genetic linkage between myopia and Han Chinese patients with a family history of the disease. Methods: One hundred seventy-six Han Chinese patients from 34 extended families were given eye examinations, and mean spherical equivalent (MSE) in diopters (D) was calculated by adding the spherical component of the refraction to one-half the cylindrical component and taking the average of both eyes. The MSE was converted to a binary phenotype, where all patients with an MSE of -1.00 D or less were coded as affected. Unaffected individuals had an MSE greater than 0.00 D (ages 21 years and up), +1.50 (ages 11-20), or +2.00 D (ages 6-10 years). Individuals between the given upper threshold and -1.00 were coded as unknown. Patients were genotyped on an exome chip. Three types of linkage analyses were performed: single-variant two-point, multipoint, and collapsed haplotype pattern (CHP) variant two-point. Results: The CHP variant two-point results identified a significant peak (heterogeneity logarithm of the odds [HLOD] = 3.73) at 10q26.13 in TACC2. The single-variant two-point and multipoint analyses showed highly suggestive linkage to the same region. The single-variant two-point results identified 25 suggestive variants at HTRA1, also at 10q26.13. Conclusions: We report a significant genetic linkage between myopia and Han Chinese patients at 10q26.13. 10q26.13 contains several good candidate genes, such as TACC2 and the known age-related macular degeneration gene HTRA1. Targeted sequencing of the region is planned to identify the causal variant(s).

Aspheric Micro-monovision LASIK in Correction of Presbyopia and Myopic Astigmatism: Early Clinical Outcomes in a Chinese Population.

PURPOSE: To analyze early clinical outcomes of aspheric micro-monovision LASIK for correction of presbyopia and myopia with or without astigmatism. METHODS: Prospective, non-comparative case series of 80 eyes of 40 patients with a mean age of 43.4 ± 4.9 years (range: 38 to 63 years) treated bilaterally using an aspheric micro-monovision protocol. The target refraction was plano for the distance eye and between -0.75 and -2.25 diopters (D) for the near eye. Visual acuity, ocular aberrations, contrast sensitivity, corneal topography, amplitude of accommodation, binocular sensorial function, and satisfaction score questionnaires were evaluated at 3 months after surgery. RESULTS: Three months after surgery, the mean spherical equivalent (SE) refraction in the distance eye was -0.08 ± 0.27 D, whereas the attempted and achieved SE in the near eye were -1.41 ± 0.28 and -1.32 ± 0.35 D, respectively. Ninety-three percent of eyes were within ±0.50 D of target correction of SE. The uncorrected distance visual acuity (UDVA) after surgery was -0.10 ± 0.06 logMAR (20/15.5), 0.22 ± 0.12 logMAR (20/34), and -0.11 ± 0.06 logMAR (20/15), for distance eyes, near eyes, and binocularly, respectively. Ninety-five percent of patients achieved simultaneously uncorrected distance visual acuity 0.0 logMAR (20/20) or better and uncorrected near visual acuity J2 (20/25) or better. Stability was achieved from 1 week of follow-up. The overall satisfaction score for surgery was 92 ± 6. CONCLUSIONS: The aspheric micro-monovision protocol provided a well-tolerated and effective means for treating myopic astigmatism and alleviating presbyopic symptoms simultaneously. [J Refract Surg. 2016;32(10):680-685.].

East London's Homeless: a retrospective review of an eye clinic for homeless people.

BACKGROUND: There is very little published work on the visual needs of homeless people. This paper is the first study to investigate the visual needs of homeless people in the UK. Although similar work has been done in other countries, this study is unique because the United Kingdom is the only country with a National Health Service which provides free healthcare at the point of access. This study analysed the refractive status of the sample used, determined the demographics of homeless people seeking eye care and established if there is a need for community eye health with access to free spectacle correction in East London. METHODS: This retrospective case study analysed the clinical records of 1,141 homeless people using the Vision Care for Homeless People services at one of their clinics in East London. All eye examinations were carried out by qualified optometrists and, where appropriate, spectacles were dispensed to patients. Data captured included age, gender, ethnicity and refractive error. Results were analysed using two-sample t-tests with Excel and Minitab. RESULTS: Demographics of age, gender and ethnicity are described. Spherical equivalents (SE) were calculated from prescription data available for 841 clinic users. Emmetropia was defined as SE-0.50DS to +1DS, myopia as SE < -0.50DS, and hyperopia as SE > +1DS. The majority of clinic users were male (79.2 %, n = 923). Approximately 80 % (n = 583) of clinic users were white, 10 % (n = 72) were 'black', 4 % (n = 29) 'Asian' and the remaining 5.6 % (n = 40) were of 'mixed ethnicity' and 'other' groups. The mean age of females attending the clinic was significantly lower than that of males (45.9 years, SD = 13.8 vs' 48.4 years, SD = 11.8) when analysed using a two-sample t-test (t (317) = 2.44, p = 0.02). One third of service users were aged between 50-59 years. Myopia and hyperopia prevalence rates were 37.0 % and 21.0 % respectively. A total of 34.8 % of homeless people were found to have uncorrected refractive error, and required spectacle correction. CONCLUSIONS: This study has identified a high proportion of uncorrected refractive error in this sample and therefore a need for regular eye examinations and provision of refractive correction for homeless people.

Biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy.

PURPOSE: To determine the biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy (TAO). METHODS: Retrospective, observational study (between October 2012 and September 2014) was performed. Patients with TAO undergoing orbital decompression for stable proptosis received ophthalmic examinations, including Hertel exophthalmometry, A-scan biometry, autorefraction measures, corneal topography, and wavefront aberration measures, before orbital decompression and again 2 months after surgery. RESULTS: Included in the study were 43 eyes from 23 patients. The mean exophthalmometric value decreased by 4.1 mm 2 months after orbital decompression (P<0.001). On average, axial length (AL) increased significantly by 0.08 mm (P<0.001); specifically, 37 (86%) of the 43 eyes had increased AL. Whereas anterior chamber depth and lens thickness showed no significant changes (P=0.086 and P=0.905, respectively), the mean spherical refraction and spherical equivalent (SE) decreased by 0.35 and 0.48 D, respectively (P=0.008 and P<0.001, respectively). However, cylindrical refraction and axis showed no significant changes (P=0.057 and P=0.218, respectively). The changes in AL and SE were significantly correlated (R=-0.411, P=0.009). Notably, there were no changes in corneal topography or wavefront aberration after orbital decompression. CONCLUSIONS: TAO patients who underwent orbital decompression showed myopic refractive change via increase in AL. Possible refractive changes should be considered in cases of TAO complaining of decreased visual acuity after orbital decompression.

Myopia in young patients with type 1 diabetes mellitus.

INTRODUCTION: This study aimed to evaluate the proportion of young patients with type 1 diabetes mellitus (T1DM) who have myopia, as well as the risk factors associated with myopia in this group. METHODS: In this cross-sectional study, patients aged < 21 years with T1DM for ≥ 1 year underwent a comprehensive eye examination. Presence of parental myopia, and average hours of near-work and outdoor activity were estimated using a questionnaire. Annualised glycosylated haemoglobin (HbA1c), defined as the mean of the last three HbA1c readings taken over the last year, was calculated. Multivariate analysis using genetic, environmental and diabetes-related factors was done to evaluate risk factors associated with myopia. RESULTS: Of the 146 patients (mean age 12.5 ± 3.6 years) recruited, 66.4% were Chinese and 57.5% were female. Myopia (i.e. spherical equivalent [SE] of -0.50 D or worse) was present in 96 (65.8%) patients. The proportion of patients with myopia increased from 25.0% and 53.6% in those aged < 7.0 years and 7.0-9.9 years, respectively, to 59.2% and 78.4% in those aged 10.0-11.9 years and ≥ 12.0 years, respectively. Higher levels of SE were associated with lower parental myopia (p = 0.024) and higher annualised HbA1c (p = 0.011). CONCLUSION: Compared to the background population, the proportion of myopia in young patients with T1DM was higher in those aged < 10 years but similar in the older age group. Myopia was associated with a history of parental myopia. Environmental risk factors and poor glycaemic control were not related to higher myopia risk.

Ethnic variation in rhegmatogenous retinal detachments.

PURPOSE: We aimed to investigate the clinical variation of rhegmatogenous retinal detachments (RD) in patients of different ethnicities. METHODS: Patients presenting with a primary RD from two ethnic groups were recruited from our tertiary referral hospital between August 2010 and December 2012. Patients who self-reported their ethnic origin either as European Caucasian (EC) or South Asian (SA) were included. Exclusion criteria included trauma, previous vitreoretinal procedures, age under 18 years, complicated cataract surgery and the presence of syndromes known to be associated with a high prevalence of RD. Detailed phenotypic data were collected. Descriptive and comparative statistical analyses were undertaken. RESULTS: 1269 Patients were recruited. 1173 (92.4%) were EC. Mean age of onset was 58.3 years (EC) and 54.5 years (SA) (P=0.006). 75.3% EC and 58.4% SA were phakic (P<0.001). 12.8% of EC and 19.4% of SA patients had a lattice retinal degeneration in the affected eye (P=0.003). Refractive myopia was greater in SA patients (mean: -6.1DS) than EC (-4.2DS) (P=0.032). Additionally, SA patients had a greater mean axial length (25.65 mm) than EC (25.06 mm) (P=0.014). No differences were demonstrated in laterality, family history, type of retinal break or macular status. CONCLUSIONS: SA patients present with RD at an earlier age and have a more severe phenotype than ECs. Future management strategies for RD may need to reflect these differences.

Outcomes of the Haigis-L formula for calculating intraocular lens power in Asian eyes after refractive surgery.

PURPOSE: To report outcomes using the Haigis-L formula to calculate intraocular lens (IOL) power in Asian eyes with long axial lengths (ALs) that had previous myopic laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK). SETTING: Singapore National Eye Centre, Singapore. DESIGN: Retrospective case series. METHODS: Patients with ALs greater than 25.0 mm and previous myopic LASIK or PRK who had phacoemulsification were analyzed. The emmetropic IOL power was back-calculated using the 1-month postoperative manifest refraction and compared with the emmetropic IOL power calculated with the Haigis-L formula. The primary outcome measure was the mean arithmetic prediction error, defined as the difference between the actual postoperative refractive error and the intended formula-derived refractive target. RESULTS: Sixty-two eyes (52 patients) were analyzed. The mean arithmetic prediction error was -0.44 diopter (D) ± 0.98 (SD) and the mean absolute error, 0.87 ± 0.62 D. The mean arithmetic prediction error was -0.52 ± 0.96 D in eyes with an AL less than 27.0 mm and -0.36 ± 1.00 D in eyes with an AL of 27.0 mm or greater (P = .463). The predictability of being within ±0.50 D and ±1.00 D of target was 35.7% and 63.1%, respectively, overall; 31.6% and 60.5%, respectively, in eyes with an AL less than 27.0 mm; and 39.1% and 65.2%, respectively, in eyes with an AL of 27.0 mm or greater (P = .772). CONCLUSION: The Haigis-L formula was acceptably accurate in predicting and achieving target outcomes after phacoemulsification in Asian eyes with a long AL that had previous myopic LASIK or PRK. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

The distribution of intraocular pressure and associated systemic factors in a Korean population: the Korea National Health and Nutrition Examination Survey.

PURPOSE: To investigate the distribution of intraocular pressure (IOP) and its associated factors in a large Korean population based on the data from the nationwide cross-sectional survey. METHODS: We obtained 2009-2010 data from the Korea National Health and Nutrition Examination Survey (KNHANES) (n = 17 901). After excluding individuals under 19 years of age, a total of 13 431 subjects were enrolled. All participants completed a comprehensive questionnaire and underwent an ocular examination including measurement of IOP by Goldmann applanation tonometry, as well as a systemic evaluation including blood pressure measurements, anthropometry and blood tests. RESULTS: The mean IOP in the right eye was 13.99 ± 2.75 mmHg, and in the left eye, 13.99 ± 2.75 mmHg, representing no significant bilateral difference. There was, however, a significant difference between males (14.19 ± 2.78 mmHg) and females (13.79 ± 2.70 mmHg) (p < 0.001). Multiple regression analysis revealed that higher IOP was significantly correlated with male sex, higher myopic refractive error, higher body mass index, higher systolic blood pressure, higher fasting plasma glucose and higher total cholesterol (all p < 0.05). On the other hand, age, histories of smoking or migraine or cold hands/feet were not significantly correlated with IOP (all p > 0.05). CONCLUSIONS: In the general Korean population, IOP increases with male sex and increasing myopia. Further, IOP is significantly correlated with systemic factors relating to cardiovascular disease and metabolic syndrome.

Myopia, axial length, and age-related cataract: the Singapore Malay eye study.

PURPOSE: To describe the associations of myopia and axial length (AL) with age-related cataract in an Asian population in Singapore. METHODS: A population-based cross-sectional study that examined 3280 (78.7% response) adults of Malay ethnicity aged 40 to 80 years. Refractive error was determined by subjective refraction and AL was measured using the Zeiss IOL-Master. Digital slit lamp and retroillumination lens photographs were taken and graded for age-related nuclear, cortical, and posterior subcapsular (PSC) cataract following the Wisconsin system. RESULTS: After excluding eyes with prior refractive or cataract surgery, 5474 eyes with gradable lens photographs were analyzed. In multivariate analyses adjusting for age, sex, body mass index, systolic blood pressure, glycosylated hemoglobin, smoking status, and education, myopia (spherical equivalent less than -0.5 diopter [D]) was associated with an increased prevalence of nuclear (OR: 4.99, 95% CI: 3.72­6.69) and PSC cataract (OR: 1.34, 95% CI: 1.30-1.39) but not with cortical cataract (OR: 0.85, 95% CI: 0.68-1.08) compared with emmetropia. Per-millimeter increase in AL was not associated with any of the three cataract subtypes. When myopia was defined as spherical equivalent of less than -5.0 D to -6.0 D, the OR of myopia for PSC cataract increased dramatically. CONCLUSIONS: Our study shows that myopia, but not AL, was associated with nuclear cataract, supporting the concept of index myopia with aging. Myopia, especially high myopia, may predispose to PSC cataract formation. Clinically, ophthalmologists should be aware that risk of PSC cataract appears to vary by refractive status.

Visual acuity and refraction by age for children of three different ethnic groups in Paraguay / Acuidade visual e refração por idade para crianças de três grupos étnicos diferentes no Paraguai

PURPOSE: To characterize refractive errors in Paraguayan children aged 5-16 years and investigate effect of age, gender, and ethnicity. METHODS:The study was conducted at 3 schools that catered to Mennonite, indigenous, and mixed race children. Children were examined for presenting visual acuity, autorefraction with and without cycloplegia, and retinoscopy. Data were analyzed for myopia and hyperopia (SE ≤-1 D or -0.5 D and ≥2 D or ≥3 D) and astigmatism (cylinder ≥1 D). Spherical equivalent (SE) values were calculated from right eye cycloplegic autorefraction data and analyzed using general linear modelling. RESULTS: There were 190, 118, and 168 children of Mennonite, indigenous and mixed race ethnicity, respectively. SE values between right/left eyes were nonsignificant. Mean visual acuity (VA) without correction was better for Mennonites compared to indigenous or mixed race children (right eyes: 0.031, 0.090, and 0.102 logMAR units, respectively; P<0.000001). There were 2 cases of myopia in the Mennonite group (1.2%) and 2 cases in the mixed race group (1.4%) (SE ≤-0.5 D). The prevalence of hyperopia (SE ≥2 D) was 40.6%, 34.2%, and 46.3% for Mennonite, indigenous and mixed race children. Corresponding astigmatism rates were 3.2%, 9.5%, and 12.7%. Females were slightly more hyperopic than males, and the 9-11 years age group was the most hyperopic. Mennonite and mixed race children were more hyperopic than indigenous children. CONCLUSIONS: Paraguayan children were remarkably hyperopic and relatively free of myopia. Differences with regard to gender, age, and ethnicity were small.

OBJETIVO: Caracterizar os erros de refração em crianças paraguaias com idades entre 5 e 16 anos e investigar efeito da idade, gênero e etnia. MÉTODOS: O estudo foi realizado em três escolas que atendiam crianças de etnia Menonita, indígena e mista. As crianças foram examinadas em relação à acuidade visual, autorrefração com e sem cicloplegia, e retinoscopia. Os dados foram analisados ​​para correção de miopia e hipermetropia (EE ≤-1 D ou -0,5D e ≥ 2D ou ≥3 D) e astigmatismo (cilindro ≥1 D). Valores equivalentes esféricos (EE) foram calculados a partir dos dados de autorrefração cicloplegiada do olho direito e analisados ​​por meio de modelagem linear geral. RESULTADOS: Foram avaliadas 190, 118 e 168 crianças de etnias Menonita, indígena e mista, respectivamente. Diferenças entre os valores de EE de olhos direitos e esquerdos não foram significantes. A acuidade visual (AV) sem correção foi melhor para Menonitas em relação às crianças da etnia indígena ou mista (olho direito: 0,031, 0,090 e 0,102 logMAR, respectivamente; P<0,000001). Houve 2 casos de miopia no grupo Menonita (1,2%) e 2 casos no grupo de etnia mista (1,4%) (SE ≤-0,5 D). A prevalência de hipermetropia (SE ≥2 D) foi de 40,6%, 34,2% e 46,3% para as etnias Menonita, indígena e mista. As taxas correspondentes de astigmatismo foram de 3,2%, 9,5% e 12,7%. As mulheres foram ligeiramente mais hipermétropes do que os homens, e o grupo de 9 a 11 anos de idade foi a mais hipermétrope. Crianças da etnia Menonita e mista se mostraram mais hipermétropes do que as crianças indígenas. CONCLUSÕES: As crianças paraguaias são notavelmente hipermétropes e relativamente livres de miopia. Diferenças com relação ao sexo, idade e etnia são pequenas.

Racial variations in the prevalence of refractive errors in the United States: the multi-ethnic study of atherosclerosis.

PURPOSE: To describe racial variations in the prevalence of refractive errors among adult white, Chinese, Hispanic, and black subjects in the United States. DESIGN: Cross-sectional data from a prospective cohort study-the Multi-Ethnic Study of Atherosclerosis (MESA). METHODS: A total of 6000 adults aged 45 to 84 years living in the United States participated in the study. Refractive error was assessed, without cycloplegia, in both eyes of all participants using an autorefractor. After excluding eyes with cataract, cataract surgery, or previous refractive surgery, the eye with the larger absolute spherical equivalent (SE) value for each participant was used to classify refractive error. Any myopia was defined as SE of -1.0 diopters (D) or less; high myopia was defined as SE of -5.0 D or less; any hyperopia was defined as SE of +1.0 D or more; clinically significant hyperopia was defined as SE of +3.0 D or more. Astigmatism was defined as a cylinder value of +1.0 D or more. RESULTS: After excluding 508 participants with cataracts in both eyes, 838 participants with cataract surgery, 90 participants with laser refractive surgery, and 134 participants who refused to remove their contact lenses for the refraction measurement, 4430 adults with refractive error assessment in at least 1 eye contributed to the analysis. The prevalence of myopia among MESA participants was 25.1%, with lowest rates in Hispanic participants (14.2%), followed by black (21.5%) and white participants (31.0%), and highest rates in Chinese participants (37.2%). The overall rates of high myopia and astigmatism were 4.6% and 45.0%, respectively, with Chinese subjects also having the highest rates of high myopia (11.8%) and astigmatism (53.4%). The overall prevalence of any hyperopia was 38.2% and clinically significant hyperopia was 6.1%, with Hispanic participants having the highest rates of hyperopia (50.2%) and clinically significant hyperopia (8.8%). In multivariate analyses adjusting for age, sex, race, and study site, higher education level, being employed, and being taller were associated with a higher prevalence of myopia. In contrast, lower educational level and being shorter were associated with a higher prevalence of hyperopia. CONCLUSIONS: Myopia and astigmatism were most prevalent in the Chinese population, with Chinese subjects having 3 times the prevalence of myopia as Hispanic subjects. Hyperopia was most common in Hispanic subjects. These findings provide further insights into variations in refractive errors among different racial groups and have important implications for the eye care services in the United States.

Parental smoking and childhood refractive error: the STARS study.

PURPOSE: To assess the relationship between parental smoking and childhood refractive errors in Singapore Chinese children aged 6-72 months recruited through the STrabismus, Amblyopia, and Refractive errors in Singaporean children study. METHODS: A total of 4164 children were recruited, with a positive response rate of 72.3% (n=3009). Cycloplegic refraction measurements were obtained from all children by trained eye professionals. Parents underwent an interviewer-administered questionnaire with information on demographics, lifestyle, and parental smoking history being obtained. RESULTS: Spherical equivalent readings were obtained for 87.7% of the children. In all, 52.1% were male (n=1375). The overall prevalence of myopia (at least -0.5 D) was 11.0%. Overall, 37.1% of the fathers interviewed gave a history of smoking. Among the mothers interviewed, 9.2% gave a history of smoking, 6.6% had smoked during the child's life, and 2.2% had smoked during the pregnancy. Maternal history of ever smoking, smoking during child's life, and smoking during pregnancy were associated with decreased odds ratio (OR) of childhood myopia (OR 0.50 (P=0.01), OR 0.39 (P=0.01), and OR 0.3 (P=0.14), respectively). Paternal history of smoking was associated with decreased OR of childhood myopia (OR of 0.72 (P=0.02)). CONCLUSION: In light of this finding of an inverse association between parental smoking and childhood myopia, further studies are suggested to better understand the role of nicotinic acetylcholine receptor pharmacology in ocular development. This may pave the way for the development of targeted treatment strategies for prevention of myopia.

Corneal power estimation for intraocular lens power calculation after corneal laser refractive surgery in Chinese eyes.

PURPOSE: To develop and evaluate an algorithm for corneal power estimation in intraocular lens (IOL) power calculation after corneal laser refractive surgery in Chinese eyes. SETTING: Guangdong Eye Institute, Guangdong Academy of Medical Sciences, Guangzhou, China. DESIGN: Prospective comparative case series. METHODS: Corneal parameters in Chinese eyes and German eyes were measured using a rotating Scheimpflug camera. Corneal power was simplified as a corrective algorithm: K(C) = 1.114 × K(M) + K(2) (K(M) = measured K reading; K(2) = K(P) - K(A) × K(P) × CT/1.376; K(A) = anterior corneal power; K(P) = posterior corneal power; CCT = central corneal thickness). The variation and change in K(2) induced by refractive surgery were analyzed in Chinese eyes. The corrective algorithm was identified as K(C) = 1.114 × K(M) - 6.20. The method was evaluated in Chinese cataract cases after refractive surgery using the Haigis formula. RESULTS: No difference in anterior corneal radius (R(A)) or CCT between Chinese eyes and German eyes were found; however, the posterior corneal radius (R(P)), R(A)/R(P) ratio, keratometric index, and K(2) were different. The mean K(2) was -6.23 diopters (D) ± 0.24 (SD) in Chinese eyes and -6.12 ± 0.23 D in German eyes (P<.01). The mean change in K(2) induced by refractive surgery was -0.02 ± 0.06 D. The median absolute prediction error in IOL power calculation was 0.43 D (range 0.01 to 1.80 D). CONCLUSION: The algorithm was a relatively reliable method in IOL power calculation after corneal refractive surgery in Chinese eyes.

Comparison of corneal thickness and curvature in myopic and keratoconic eyes of patients from French Caribbean Isles and continental France.

PURPOSE: To evaluate the corneal thickness and curvature of myopic and patients with keratoconus from two countries. METHODS: This cross-sectional study was conducted at Cabinet Opale, Fort de France, French West Indies and University Hospital of Bordeaux, France. Corneal thickness and curvature were assessed in 170 keratoconic eyes of 89 residents of the French Caribbean Islands (FCI) and 159 keratoconic eyes of 91 residents of the Aquitaine region of southwest France. A group of age-matched keratoconus-free patients who had been referred for refractive surgery owing to myopia (173 FCI [173 eyes; 87 individuals] and Aquitaine [181 eyes; 93 individuals]) were also assessed. RESULTS: The mean age at keratoconus diagnosis was significantly higher among FCI than Aquitaine residents (p = 0.009). The mean keratometric (Km) reading was statistically higher for keratoconic FCI than Aquitaine patients, at 48.06 versus 46.21 diopters (p = 0.001). This difference was more pronounced among patients aged >40 years than those ≤40 years (p = 0.009). Patients with keratoconus showed no significant difference in mean central corneal thickness and thinnest corneal point values, irrespective of region. Myopic individuals from the FCI, however, had significantly lower mean central corneal thickness and thinnest corneal point measurements than Aquitaine myopics, irrespective of age group (p ≤ 0.0008). CONCLUSION: The corneas of patients with keratoconus of African-Caribbean and Caucasian origins are of similar thickness. Myopic African-Caribbean patients referred for refractive surgery tend to present with thinner corneas than Caucasians.

Intraocular pressure and central corneal thickness in the COMET cohort.

PURPOSE: To describe intraocular pressure (IOP) and central corneal thickness (CCT) in ethnically diverse, myopic young adults enrolled in COMET (the Correction of Myopia Evaluation Trial) and their association with ocular and demographic factors. METHODS: IOP (Goldmann tonometry), CCT (handheld pachymetry), refractive error (cycloplegic autorefraction), and ocular components (A-scan ultrasonography) were measured in 385 of the original 469 subjects (mean age = 20.3 ± 1.3 years). Summary statistics for descriptive analysis, Pearson correlation coefficients, and linear regression models to formally test the association of IOP and CCT with other covariates were used. RESULTS: Mean IOP was 15.1 ± 0.1 mm Hg and differed by ethnicity and CCT but did not vary by gender, magnitude of myopia, or vitreous chamber depth (VCD). Adjusting for CCT, IOP in black participants was 1.8 mm Hg higher than in Hispanics (p = 0.0001) and 0.8 mm Hg higher than in whites (p = 0.03). Mean CCT was 562.4 ± 1.8 µm and differed by ethnicity, VCD, and IOP after adjusting for covariates. Blacks had thinner corneas than Asians, whites, and Hispanics, with adjusted differences of 15.4, 11.8, and 15.3 µm (p = 0.03, < 0.01 and < 0.01), respectively. Eyes with shorter VCD (<17.8 mm) had 8.0-µm thinner CCT (p = 0.03). CCT did not vary by gender or magnitude of myopia. Overall, a modest positive correlation (r = 0.25, P < 0.0001) was found between IOP and CCT, which varied by ethnicity in Asians (r = 0.47; p = 0.008), blacks (r = 0.29; p = 0.002), and whites (r = 0.24; p = 0.002). CONCLUSIONS: Myopic, black young adults had higher IOP and thinner corneas relative to other ethnic groups, suggesting that evaluation of these parameters during routine examination of these individuals should begin at a young age. Their thinner CCT should also be considered in evaluations for refractive surgery.