Prevalence and risk factors for refractive errors and ocular biometry parameters in an elderly Asian population: the Singapore Longitudinal Aging Study (SLAS)

Purpose

To determine the prevalence rates of refractive errors and pattern of ocular biometry in a multi-ethnic elderly Asian population.

Methods

A population-based study of 1835 residents aged 55–85 years, evaluating the refractive error and ocular biometry parameters, including axial length (AL) and anterior chamber depth.

Results

The age-standardized prevalence of myopia, hyperopia, astigmatism, and anisometropia were 30.0% (95% confidence interval (CI): 29.6, 30.4), 41.5% (95% CI: 41.1, 41.9), 43.5% (95% CI: 43.1, 44.0), and 22.1% (95% CI: 21.7, 22.4), respectively. Male gender (P=0.02), age ≥75 years (P=0.033), and higher educational level (P<0.001) were significantly associated with higher rates of myopia in multivariate analyses. The prevalence of astigmatism was higher in persons with diabetes (odds ratio (OR) 1.4, 95% CI: 1.03, 1.90, P=0.031). AL was longer in Chinese than other ethnic groups (23.7 vs23.4 mm, P=0.018), and in men compared with women (24.2 vs23.4 mm, P<0.001). AL was associated with increasing height (AL increased by 0.3 mm for every 10 cm increase in height, P<0.001).

Conclusion

There is a high prevalence of myopia in elderly Singaporeans, consistent with trends seen in younger populations in Asia. Male gender and higher education were independent risk factors for myopia. These data suggest that higher rates of myopia in East Asians compared with Caucasians may not be a recent phenomenon.     

Prevalence rates of refractive errors in Sumatra,Indonesia

PURPOSE: To determine the prevalence rates of myopia, hyperopia, astigmatism, and anisometropia in a prevalence survey of adults in Sumatra, Indonesia. METHODS: A population-based prevalence survey of 1043 adults 21 or more years of age was conducted in five rural villages and one provincial town of the Riau Province, Sumatra, Indonesia. A one-stage household cluster sampling procedure was used wherein 100 households were selected from each village or town. Refractive error measurements were obtained with one of two handheld autorefractors. Household interviews were conducted to obtain information on relevant lifestyle risk factors. RESULTS: The age-adjusted overall prevalence rates of myopia (SE [spherical equivalent] at least -1.0 D), hyperopia (SE of at least +1.0 D), astigmatism (cylinder of at least -1.0 D), and anisometropia (SE difference of +1.0 D) were 26.1% (95% confidence interval [CI]: 23.4-28.8), 9.2% (95% CI: 7.4-11.0), 18.5% (95% CI: 16.2-20.8), and 15.1% (95% CI: 12.9-17.4), respectively. The age-adjusted overall prevalence rate of high myopia (SE at least -6.0 D) was 0.8% (95% CI: 0.2-1.5). In a multiple logistic regression model, myopia rates varied with age and increased with income. Hyperopia, astigmatism, and anisometropia rates were independently higher in older adults. CONCLUSIONS: The prevalence rates of myopia in provincial Sumatra are higher than the rates in white populations, but lower than the rates in other urbanized Asian countries such as Singapore. The prevalence rate of high myopia is lower than in most other populations, and other refractive errors are common.     

Refractive Errors in Koreans: The Korea National Health and Nutrition Examination Survey 2008-2012

PurposeOur study provides epidemiologic data on the prevalence of refractive errors in all age group ≥5 years in Korea.MethodsIn 2008 to 2012, a total of 33,355 participants aged ≥5 years underwent ophthalmologic examinations. Using the right eye, myopia was defined as a spherical equivalent (SE) less than -0.5 or -1.0 diopters (D) in subjects aged 19 years and older or as an SE less than -0.75 or -1.25 D in subjects aged 5 to 18 years according to non-cycloplegic refraction. Other refractive errors were defined as follows: high myopia as an SE less than -6.0 D; hyperopia as an SE larger than +0.5 D; and astigmatism as a cylindrical error less than -1.0 D. The prevalence and risk factors of myopia were evaluated.ResultsPrevalence rates with a 95% confidence interval were determined for myopia (SE <-0.5 D, 51.9% [51.2 to 52.7]; SE <-1.0 D, 39.6% [38.8 to 40.3]), high myopia (5.0% [4.7 to 5.3]), hyperopia (13.4% [12.9 to 13.9]), and astigmatism (31.2% [30.5 to 32.0]). The prevalence of myopia demonstrated a nonlinear distribution with the highest peak between the ages of 19 and 29 years. The prevalence of hyperopia decreased with age in subjects aged 39 years or younger and then increased with age in subjects aged 40 years or older. The prevalence of astigmatism gradually increased with age. Education was associated with all refractive errors; myopia was more prevalent and hyperopia and astigmatism were less prevalent in the highly educated groups.ConclusionsIn young generations, the prevalence of myopia in Korea was much higher compared to the white or black populations in Western countries and is consistent with the high prevalence found in most other Asian countries. The overall prevalence of hyperopia was much lower compared to that of the white Western population. Age and education level were significant predictive factors associated with all kinds of refractive errors.     

Impact of laser refractive surgery on ocular alignment in myopic patients

Purpose

To evaluate the impact of myopic keratorefractive surgery on ocular alignment.

Methods

This prospective study included 194 eyes of 97 myopic patients undergoing laser refractive surgery. All patients received a complete ophthalmic examination with particular attention to ocular alignment before and 3 months after surgery.

Results

Patients with a mean age of 26.6 years and a mean refractive error of −4.83 diopters (D) myopia were treated. Asymptomatic ocular misalignment was present preoperatively in 46 (47%) patients: a small-angle heterophoria (1–8 prism diopters, PD) in 36% and a large-angle heterophoria (>8 PD)/heterotropia in 11%. Postoperatively, the change in angles of 10 PD or greater occurred in 3% for distance and 6% for near fixation: in 7% of the patients with orthophoria, in 3% of those with a small-angle heterophoria, and in 18% of those with a large-angle heterophoria/heterotropia. No patient developed diplopia. The preoperative magnitude of myopia or postoperative refractive status was not related to the change in ocular alignment. The higher anisometropia was associated with a decrease in deviation (P=0.041 for distance and P=0.002 for near fixation), whereas the further near point of convergence tended to be related with an increase in near deviation (P=0.055).

Conclusions

Myopic refractive surgery may cause a change in ocular alignment, especially in cases with a large-angle heterophoria/heterotropia. There is also a chance of improvement of misalignment in patients with anisometropia.     

Factors Influencing the Prevalence of Amblyopia in Children with Anisometropia

Purpose

To evaluate factors that can influence the prevalence of amblyopia in children with anisometropia.

Methods

We retrospectively reviewed the records of 63 children 2 to 13 years of age who had anisometropic amblyopia with a difference in the refractive errors between the eyes of at least two diopters (D). The type of anisometropia (myopia, hyperopia, and astigmatism), degree of anisometropia (<2-3 D, <3-4 D, or >4 D), best corrected visual acuity (BCVA) of the amblyopic eye at the time of initial examination, BCVA differences between sound and amblyopic eyes, whether or not occlusion therapy was performed, compliance with occlusion therapy, and the patient''s age when eyeglasses were first worn were investigated.

Results

There was an increase in the risk of amblyopia with increased magnitude of anisometropia (p=0.021). The prevalence of amblyopia was higher in the BCVA <20/40 group and in patients with BCVA differences >4 lines between sound and amblyopic eyes (p=0.008 and p=0.045, respectively). There was no statistical relationship between the prevalence of amblyopia and the type of anisometropia or the age when eyeglasses were first worn. Poor compliance with occlusion therapy was less likely to achieve successful outcome (p=0.015).

Conclusions

Eyes with poor initial visual acuities of <20/40, a high magnitude of anisometropia, and a >4 line difference in the BCVA between sound and amblyopic eyes at the initial visit may require active treatment.     

Ocular residual astigmatism's effect on high myopic astigmatism LASIK surgery

Purpose

To analyze the effect of ocular residual astigmatism (ORA) on the effectiveness of LASIK for treating high myopic astigmatism.

Methods

This is an observational, cross-sectional study. We studied 116 consecutive myopic eyes with −3 diopters (D) or more of astigmatism that underwent LASIK surgery. The magnitude of uncorrected residual refractive astigmatism 3 months postoperatively was measured.

Results

The mean preoperative cylinder was −4.0±0.83 D (range, −7.5 to −3 D) and the mean preoperative ORA was 0.82±0.5 D. The mean residual refractive cylinder 3 months postoperatively was −0.78±0.83 D (range, −3 to 0 D). No correlation was found between ORA and the refractive cylinder 3 months postoperatively (P=0.6).

Conclusion

In eyes with high myopic astigmatism undergoing LASIK, ORA was not correlated with the residual postoperative cylinder.     

Prevalence of refractive errors in teenage high school students in Singapore

We aimed to study the prevalence of refractive conditions in Singapore teenagers. Grade 9 and 10 students (n = 946) aged 15-19 years from two secondary schools in Singapore were recruited. The refractive errors of the students' eyes were measured using non-cycloplegic autorefraction. Sociodemographic data and information on risk factors for myopia (such as reading and writing) were also obtained using an interviewer-administered questionnaire. The prevalence of refractive conditions was found to be: myopia [spherical equivalent (SE) at least -0.50 D] - 73.9%, hyperopia (SE at least +0.50 D) - 1.5%, astigmatism (cylinder at least -0.50 D) - 58.7% and anisometropia (SE difference at least 1.00 D) - 11.2%. After adjusting for age and gender, currently doing more than 20.5 h of reading and writing a week was found to be positively associated with myopia [odds ratio 1.12 (95% CI 1.04-1.20, p = 0.003)], as was reading and writing at a close distance and a better educational stream. The prevalence of myopia (73.9%) in Singapore teenagers is high. Current reading and writing habits, reading at close distances and a better educational stream are possible risk factors for myopia.     

Mini-incision cataract surgery and toric lens implantation for the reduction of high myopic astigmatism in patients with pellucid marginal degeneration

Purpose

To evaluate the clinical outcomes, safety, and efficacy of cataract surgery with the implantation of a toric intraocular lens (IOL) in eyes with stable pellucid marginal degeneration (PMD).

Methods

Eleven eyes (eight patients) diagnosed as stable PMD and cataract underwent mini-incision 2.2 mm cataract surgery followed by the implantation of hydrophobic toric aspheric IOL (AcrySof IQ Toric IOL, Alcon, Fort Worth, TX, USA). Perioperative variables of interest included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, and corneal topography. Paired samples t-tests were used to analyze preoperative and postoperative visual acuity, astigmatism, and spherical equivalent (SE) parameters. Follow-up was 6 months.

Results

The mean CDVA was 0.62±0.26 logMAR preoperatively and 0.07±0.07 logMAR postoperatively. The mean preoperative sphere and cylinder was −3.14±3.58D and −4.84±2.02D, respectively. The mean postoperative manifest refractive sphere and cylinder was −0.30±0.51D and −0.81±1.51D, respectively. There was a significant reduction in refractive astigmatism after toric IOL implantation (P<0.002). The toric IOL axis rotation was <5° in all cases at the final follow-up.

Conclusions

Implantation of hydrophobic toric IOL was a safe and effective surgical procedure to correct mild to moderate stable PMD.     

Refractive errors in an elderly Chinese population in Taiwan: the Shihpai Eye Study

PURPOSE: Few epidemiologic data are available on refractive status in elderly Asians. The purpose of the study was to determine prevalence and risk factors associated with refractive errors in a metropolitan elderly Chinese population in Taiwan. METHODS: A population-based survey was conducted in the Shihpai district of Taipei, Taiwan. A total of 2045 residents aged 65 years or more were randomly selected and invited to complete a comprehensive questionnaire and undertake a detailed ocular examination, including best corrected visual acuity and measurements of refractive error, using autorefraction. Of the subjects, 1361 (66.6%) participated in the ocular examination. Spherical equivalent (SE) was calculated in diopters (D), and data from right eyes were reported. RESULTS: The age- and sex-adjusted prevalence rates were determined for myopia (SE<-0.5 D, 19.4%; SE<-1.0 D, 14.5%), high myopia (SE<-6.0 D, 2.4%), hyperopia (SE>+0.5 D, 59.0%; SE>+1.0 D, 44.2%), astigmatism (cylinder<-0.5 D, 74.0%; cylinder<-1.0 D, 45.3%), and anisometropia (SE difference between right and left eyes>0.5 D, 45.2%; SE difference>1.0 D, 21.8%). The prevalence of myopia, astigmatism, and anisometropia significantly increased with age (all P<0.01). The prevalence of hyperopia tended to decrease with age. There was no gender difference in prevalence rates in any type of refractive error, except that women had a higher rate of hyperopia (SE>+1.0 D) than men (P=0.004). Multivariate regression analysis showed that myopia was weakly associated with higher educational level. The severity of lens nuclear opacity was positively associated with the rates of myopia and negatively associated with the rates of hyperopia. CONCLUSIONS: The prevalence of myopia in this elderly Chinese population is not much higher than in similarly aged elderly white populations, compared with a much greater difference in prevalence among younger Chinese versus white people. This suggests that changing environmental factors may account for the increased prevalence of myopia in younger cohorts of Chinese.     

Astigmatism and biometric optic components of diode laser-treated threshold retinopathy of prematurity at 9 years of age

Purpose

To assess the prevalence of astigmatism and its relationship with biometric optic components in preterm school children with diode laser-treated threshold retinopathy of prematurity (ROP).

Methods

A prospective, cross-sectional study in which cycloplegic keratometry, refraction, and ultrasound biometric measurement of optic components were performed on 24 consecutive preterm children with diode laser-treated threshold ROP at the age of 9 years. The study results were compared with data on 1021 age-matched full-term control children from a national survey.

Results

The laser-treated eyes had a mean astigmatism of 3.47 D, with a mean spherical equivalent of −4.49 D. Of the 46 eyes studied, 98% of eyes showed astigmatism ≥0.5 D and 50% had high astigmatism (>3.0 D). Most astigmatic eyes (97.7%) showed with-the-rule astigmatism, with the mean plus cylinder axis at 89.30^o. Further correlation analysis showed the astigmatism in refraction was highly correlated with the corneal astigmatism (r=0.921, P<0.001) and the vertical corneal curvature (r=0.405, P=0.005). There was significantly steeper vertical corneal curvature (P=0.003) and flatter horizontal corneal curvature (P=0.031) in eyes with laser-treated ROP when compared with age-matched full-term controls. The eyes with laser-treated ROP also show significantly thicker lens (3.93 mm) and shallower anterior chamber depth (ACD; 2.92 mm) than full-term controls (P<0.001).

Conclusions

There is significantly higher prevalence and greater magnitude of astigmatism in eyes with laser-treated threshold ROP compared with full-term controls. The steeper vertical corneal curvature component contributes to the increased astigmatism in eyes with laser-treated ROP.     

Distribution of refractive error in healthy infants

PURPOSE: Few data exist regarding the upper limits of refractive error distributions in healthy infants; the data that do exist are biased because they were selected from the records of pediatric ophthalmology practices. We sought to obtain these data to validate examination failure criteria for vision screening. METHODS: We reviewed records from all children age birth to 5 years seen at the Tennessee Lions Eye Center at Vanderbilt Children's Hospital with a billing diagnosis of nasolacrimal duct obstruction and no comorbid ocular diagnoses except for refractive error. This was to avoid referral bias for any condition that could have influenced refractive error. All patients received a complete eye examination and cycloplegic refraction. Cumulative probability distribution (CPD) plots and means for spherical and cylindrical refractive error and anisometropia were prepared. RESULTS: One hundred thirty patients were studied; mean age was 15.5 +/- 9.9 months (range, 2 days to 66 months). The mean refractive error (spherical equivalent) was +1.4 D +/- 1.1 D. CPD plot analysis showed 95% of hyperopia to be < +3.25 D. Two children had myopia +1.00 D in one eye. CPD plot analysis showed 95% of astigmatism to be < +1.50 D and 95% of meridional anisometropia to be < 1.50 D. Six children had anisometropia >/=1.50 D, and 3 children had anisometropia > 3.00 D. CONCLUSIONS: At least 95% of children have hyperopia < +3.25 D, astigmatism < +1.50 D, and anisometropia < 1.50 D. This information will prove useful in identifying the natural history and prevalence of amblyogenic factors identified during preschool vision screening.     

Prevalence and risk factors for refractive errors in adult Chinese in Singapore

PURPOSE: To determine the epidemiology of refractive errors in an adult Chinese population in Singapore. METHODS: A disproportionate, stratified, clustered, random-sampling procedure was used to select names of 2000 Chinese people aged 40 to 79 years from the 1996 Singapore electoral register in the Tanjong Pagar district in Singapore. These people were invited to a centralized clinic for a comprehensive eye examination, including refraction. Refraction was also performed on nonrespondents in their homes. Myopia, high myopia, and hyperopia were defined as a spherical equivalent (SE) in the right eye of less than -0.5 D, less than -5.0 D, and more than +0.5 D, respectively. Astigmatism was defined as less than -0.5 D of cylinder. Anisometropia was defined as a difference in SE of more than 1.0 D between the two eyes. Only phakic eyes were analyzed. RESULTS: From 1717 eligible people, 1232 (71.8%) were examined. Adjusted to the 1997 Singapore population, the overall prevalence of myopia, hyperopia, astigmatism, and anisometropia was 38.7% (95% confidence interval [CI]: 35.5, 42.1), 28.4% (95% CI: 25.3, 31.3), 37.8% (95% CI: 34.6, 41.1), and 15.9% (95% CI: 13.5, 18.4), respectively. The prevalence of high myopia was 9.1% (95% CI: 7.2, 11.2), with women having significantly higher rates than men. The age pattern of myopia was bimodal, with higher prevalence in the 40 to 49 and 70 to 81 age groups and lower prevalence between those age ranges. Prevalence was reversed in hyperopia, with a higher prevalence in subjects aged 50 to 69. There was a monotonic increase in prevalence with age for both astigmatism and anisometropia. Increasing educational levels, higher individual income, professional or office-related occupations, better housing, and greater severity of nuclear opacity were all significantly associated with higher rates of myopia, after adjustment for age and sex. CONCLUSIONS: The results indicate that whereas myopia is 1.5 to 2.5 times more prevalent in adult Chinese residing in Singapore than in similarly aged European-derived populations in the United States and Australia, the sociodemographic associations are similar.     

Refractive error in Chinese with type 2 diabetes and its association with glycaemic control

Background

The aim of this study was to determine the prevalence of refractive errors and their association with glycaemic control among adults with type 2 diabetes mellitus (T2DM) in eastern China.

Methods

A community‐based survey, including 913 adults with T2DM aged 30 to 89 years, was conducted. Refractive error was assessed by autorefraction, after which subjective refraction was performed. Ocular biometric parameters were measured by non‐contact partial coherence laser interferometry. Myopia was defined as spherical equivalent (SE) less than ?0.50 dioptres (D), high myopia as SE less than ?5.00 D, hyperopia as SE greater than 0.50 D and astigmatism as cylinder less than ?0.50 D.

Results

After excluding participants who had undergone cataract surgery, 839 were included in the data analyses and 96.1 per cent were found to have refractive errors. The overall prevalences of myopia, high myopia, hyperopia and astigmatism were 28.2 per cent (95 per cent confidence interval [CI] 25.2–31.3), 6.3 per cent (95 per cent CI 4.7–8.0), 46.4 per cent (95 per cent CI 43.0–49.7) and 81.0 per cent (95 per cent CI 78.4–83.7) with no gender differences observed (all p > 0.10). In multivariate analysis, myopia was associated with decreasing age (odds ratio [OR] = 0.86, p = 0.01; per year increase), higher blood levels of haemoglobin A_1c (HbA_1c) (OR = 1.12, p = 0.05; per unit increase), higher education levels (OR = 5.10, p < 0.001; university or college versus illiterate or primary school) and the presence of nuclear cataract (OR = 2.36, p < 0.001).

Conclusions

Refractive errors may be associated with glycaemic control among T2DM patients. Longitudinal analyses are warranted to examine the relationship between changes in HbA_1c and the development of refractive errors.

     

Effects and adverse events after CXL for keratoconus are independent of age: a 1-year follow-up study

Purpose

To compare the effect, failure rate and the risks of corneal cross-linking (CXL) in keratoconus patients aged ≥35 years to patients <35 years.

Methods

In 141 eyes of 116 keratoconus patients we compared the changes in best phoropter-corrected visual acuity (BCVA) and maximum keratometry values (K_max) before and 12 months after CLX in patients aged ≥35 years (n=34, 38 eyes) to the cohort of patients below 35 years of age.

Results

Overall, CXL significantly improved BCVA from 0.487 logMAR (95% confidence interval (CI) 0.426–0.548) by −0.197 logMAR (95% CI −0.243 to −0.150; P<0.001) and reduced K_max from 48.96 diopter (Dpt) by −1.33 Dpt (95% CI −1.85 to −0.81: P<0.001). Age ≥35 years had no effect on the changes of BCVA (−0.02 (95% CI −0.13 to 0.09); P=0.757) or K_max (0.58 (95%CI −0.51 to 1.68); P=0.294) as compared with younger patients. In 54 patients (55 eyes, 38.5%) aged <35 years and in 18 patients (18 eyes, 47.4%) aged ≥35 years, BCVA increased by ≥2 Snellen lines. Failure (increase in K_max ≥1 Dpt) was observed in 17 eyes (16.5%) of patients aged <35 years and in 3 eyes (7.9%) of patients aged ≥35 years during the 12-month follow-up period. Adverse outcomes (loss of ≥2 Snellen lines) occurred in 4 (3.9%) eyes of patients aged <35 years and 1 (2.6%) eye of a patient aged ≥35 years.

Conclusion

Effects and adverse events of CXL treatment do not seem to differ between subjects younger or older than 35 years.     

Biometric Risk Factors for Corneal Neovascularization Associated with Hydrogel Soft Contact Lens Wear in Korean Myopic Patients

Purpose

To investigate the biometric risk factors for corneal surface complications associated with hydrogel soft contact lens (SCL) fitting in myopic patients in Korea.

Methods

This is a retrospective case-control study. The records of 124 subjects (124 eyes) who wore SCLs on a daily basis were reviewed. Thirty-one patients (31 eyes) who were diagnosed with corneal neovascularization (NV) while wearing SCLs were included in the complication group. Ninety-three age- and sex-matched patients (93 eyes) who wore SCLs, who did not have corneal NV and who visited our clinic for correction of refractive errors were included in the control group. The degree of spherical equivalent, astigmatism and corneal base curve radius (BCR) were compared in both groups.

Results

Patients with NV exhibited poorer best corrected visual acuity and more myopia than controls (p = 0.008 and 0.006, respectively). In univariate analysis, highly myopic patients (-9 diopters [D] or higher) were more likely to experience NV (odds ratio [OR], 2.232; 95% confidence interval [CI], 1.602 to 3.105). High astigmatism (≥2 D) increased the risk of complications (OR, 2.717; 95% CI, 1.141 to 6.451). Steep cornea, in which BCR was <7.5 mm, also raised the risk of complications (OR, 4.000; 95% CI, 1.661 to 9.804). Flat cornea was not a risk factor for the development of NV.

Conclusions

High myopia, high astigmatism, and steep cornea seemed to be risk factors in the development of corneal NV in SCL wearers.     

间歇性外斜视患者的屈光状态对立体视功能影响的研究

目的 分析合并不同屈光状态的间歇性外斜视患者立体视功能的差异。设计 回顾性病例系列。研究对象 北京同仁医院2014年7月至2015年8月间歇性外斜视需要进行手术治疗的238例患者。方法 将患者按照屈光状态分为远视组（双眼等效球镜均≥+1.00 D）、正视组（-1.00 D＜双眼等效球镜＜+1.00 D）、近视组（双眼等效球镜均≤-1.00 D）和屈光参差组（双眼等效球镜相差≥1.00 D）,用同视机检查患者的远立体视,颜少明《立体视觉检查图》检查近立体视,比较分析四组患者的远近立体视功能状况。主要指标 远立体视功能和近立体视功能。结果 （1）238例间歇性外斜视患者平均看近斜视度（45.71±18.81）△,平均看远斜视度（43.98±19.55）△,远视组、正视组、近视组和屈光参差组保留远立体功能的比率分别为23.3%、15.5%、19.7%、 18.8%,各组之间远立体视功能比较差异无统计学意义;保留近立体视功能的比率分别为66.7%、79.8%、81.6%、64.6%,屈光参差组的近立体视功能丢失最多,近视组的近立体视功能丢失最少,屈光参差组与近视组的近立体视功能有统计学差异（P=0.033）。（2）间歇性外斜视合并屈光参差的检出率为20.1%,其中近视性屈光参差所占比例（12.6%）最高,远视性屈光参差所占比例（1.3%）最低。（3）间歇性外斜视合并屈光参差的患者中,有、无远立体视的患者双眼等效球镜差值分别为（2.35±0.75）D和（2.34±1.75）D,两组间差值比较无统计学意义（P=0.21）;无近立体视患者双眼等效球镜的差值（3.11 D±2.29 D）明显大于有近立体视患者的双眼等效球镜差值（1.93 D±0.83 D）,两组的差值间比较有统计学意义（P=0.002）。结论 对于斜视角度较大的间歇性外斜视患者,不同的屈光状态对远立体视功能影响不大,屈光参差加重对近立体视功能的损伤,屈光参差度越大,近立体视功能损伤越重。（眼科, 2016, 25： 396-399）     

Refractive errors in an urban population in Southern India: the Andhra Pradesh Eye Disease Study.

PURPOSE: To assess the prevalence, distribution, and demographic associations of refractive error in an urban population in southern India. METHODS: Two thousand five hundred twenty-two subjects of all ages, representative of the Hyderabad population, were examined in the population-based Andhra Pradesh Eye Disease Study. Objective and subjective refraction was attempted on subjects >15 years of age with presenting distance and/or near visual acuity worse than 20/20 in either eye. Refraction under cycloplegia was attempted on all subjects < or =15 years of age. Spherical equivalent >0.50 D in the worse eye was considered as refractive error. Data on objective refraction under cycloplegia were analyzed for subjects < or =15 years and on subjective refraction were analyzed for subjects >15 years of age. RESULTS: Data on refractive error were available for 2,321 (92.0%) subjects. In subjects < or =15 years of age, age-gender-adjusted prevalence of myopia was 4.44% (95% confidence interval [CI], 2.14%-6.75%), which was higher in those 10 to 15 years of age (odds ratio, 2.75; 95% CI, 1.25-6.02), of hyperopia 59.37% (95% CI, 44.65%-74.09%), and of astigmatism 6.93% (95% CI, 4.90%-8.97%). In subjects >15 years of age, age-gender-adjusted prevalence of myopia was 19.39% (95% CI, 16.54%-22.24%), of hyperopia 9.83% (95% CI, 6.21%-13.45%), and of astigmatism 12.94% (95% CI, 10.80%-15.07%). With multivariate analysis, myopia was significantly higher in subjects with Lens Opacity Classification System HI nuclear cataract grade > or =3.5 (odds ratio, 9.10; 95% CI, 5.15-16.09), and in subjects with education of class 11 or higher (odds ratio, 1.80; 95% CI, 1.18-2.74); hyperopia was significantly higher in subjects > or =30 years of age compared with those 16 to 29 years of age (odds ratio, 37.26; 95% CI, 11.84-117.19), in females (odds ratio, 1.86; 95% CI, 1.33-2.61), and in subjects belonging to middle and upper socioeconomic strata (odds ratio, 2.10; 95% CI, 1.09-4.03); and astigmatism was significantly higher in subjects > or =40 years of age (odds ratio, 3.00; 95% CI, 2.23- 4.03) and in those with education of college level or higher (odds ratio, 1.73; 95% CI, 1.07-2.81). CONCLUSIONS: These population-based data on distribution and demographic associations of refractive error could enable planning of eye-care services to reduce visual impairment caused by refractive error. If these data are extrapolated to the 255 million urban population of India, among those >15 years of age an estimated 30 million people would have myopia, 15.2 million hyperopia, and 4.1 million astigmatism not concurrent with myopia or hyperopia; in addition, based on refraction under cycloplegia, 4.4 million children would have myopia and 2.5 million astigmatism not concurrent with myopia or hyperopia.     

Visual impairment in the 40- to 64-year-old population of Shahroud, Iran

Purpose

To determine the prevalence of visual impairment by age and gender in Shahroud.

Methods

Using random cluster sampling, 6311 Shahroud inhabitants who were between 40 and 64 years old were invited for ophthalmological examinations. Visual acuity worse than 0.5 LogMAR (20/60) and 1.3 LogMAR (20/400) in the better eye was regarded as low vision and blindness, respectively. The cause of blindness was determined by an ophthalmologist and in a person with more than one cause, the most correctable cause was regarded as the main cause.

Results

This study was conducted on 5190 participants (response rate: 82.2%). On the basis of presenting visual acuity, the prevalence of low vision and blindness was found to be 1.8% (95% confidence interval (CI): 1.4–2.10) and 0.5% (95% CI: 0.3–0.7), respectively. Based on corrected vision, these values were 0.5% (95% CI: 0.3–0.7) and 0.3% (95% CI: 0.1–0.4), respectively. Visual impairment increased with age in women (P<0.001). Uncorrected refractive errors (63.9%), cataract (20.2%), and amblyopia (5.9%) were the most common causes of visual impairment based on presenting vision. Based on corrected vision, however, cataract (42.5%), amblyopia (12.5%), and retinitis pigmentosa (7.5%) were the most common causes of visual impairment.

Conclusion

Although the prevalence of visual impairment in the city of Shahroud was determined to be lower than two previous studies in the country, correction of refractive errors and cataract could minimize the rate of visual impairment in this population as they were shown to comprise 85% of the causes of visual impairment. The elderly women need to receive more attention.     

The age- and gender-specific prevalences of refractive errors in Tehran: the Tehran Eye Study

purpose?To determine the age- and gender-specific prevalences of refractive errors in Tehran through a population-based study. methods?A total of 6497 citizens representing a cross-section of the population of Tehran were sampled from 160 clusters using a stratified, random, cluster sampling strategy. Eligible people were enumerated through a door-to-door household survey in the selected clusters and were invited to participate. All participants were transferred to a clinic for an extensive eye examination and interview. Refractive error was determined using manifest and cycloplegic refraction. Myopia was defined as the spherical equivalent of ?0.5 diopters (D) or more and hyperopia was defined as the spherical equivalent of more than +0.5?D. results?Of those sampled, 4565 (70.3%) people participated in the study. Refraction data for 4354 participants aged five years and over are presented. The age- and gender-standardized prevalence of myopia based on manifest refraction was 21.8% (95% confidence interval [CI], 20.1 to 23.5) and that for hyperopia was 26.0% (95% CI, 24.5 to 27.6). The prevalences based on cycloplegic refraction were 17.2% (95% CI, 15.6 to 18.8) and 56.6% (95% CI, 54.7 to 58.6), respectively. Prevalences of myopia and hyperopia differed significantly among the age and gender groups (P < 0.001). Astigmatism of 0.75 cylinder diopter or greater was present in 29.6% (95% CI, 28.0 to 31.3) of right eyes with manifest refraction and in 30.3% (95% CI, 28.5 to 32.1) with cycloplegic refraction. Among the study population, 6.1% (95% CI, 5.3 to 6.8%) had anisometropia of 1?D or more. conclusions?This report has provided details of the refractive status in the population. We have documented prevalences of myopia, hyperopia, astigmatism and anisometropia by age and gender, identifying more affected age- and gender-groups for prevention programs in the community.     

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.