儿童混合性散光的屈光演变

目的 了解混合性散光儿童屈光发展的变化规律.方法 选择门诊初诊的3～16岁儿童63例(113只眼),使用睫状肌麻痹剂检影验光后确诊为混合性散光,每年验光1次,将其连续3年的屈光结果进行追踪观察.结果 3年来散光度数改变不明显(F =0.175,P=0.840),说明其最大和最小屈光子午线的屈光状态在同步发展.而远视球镜度数逐渐降低,其差异显著有统计学意义(F =14.151,P=0.000).结论 混合性散光的儿童,随年龄增长及眼球发育,屈光状态逐渐降低甚至会向近视方向发展.该类患儿如能早期戴镜矫正,可获得较满意的视力.必须强调使用睫状肌麻痹剂检影验光对儿童混合性散光的必要性和重要性.     

Effect of Watching 3-Dimensional Television on Refractive Error in Children

Purpose

To investigate the effect of watching 3-dimensional (3D) television (TV) on refractive error in children.

Methods

Sixty healthy volunteers, aged 6 to 12 years, without any ocular abnormalities other than refractive error were recruited for this study. They watched 3D TV for 50 minutes at a viewing distance of 2.8 meters. The image disparity of the 3D contents was from -1 to 1 degree. Refractive errors were measured both before and immediately after watching TV and were rechecked after a 10-minute rest period. The refractive errors before and after watching TV were compared. The amount of refractive change was also compared between myopes and controls. The refractive error of the participants who showed a myopic shift immediately after watching TV were compared across each time point to assure that the myopic shift persisted after a 10-minute rest.

Results

The mean age of the participants was 9.23 ± 1.75 years. The baseline manifest refractive error was -1.70 ± 1.79 (-5.50 to +1.25) diopters. The refractive errors immediately after watching and after a 10-minute rest were -1.75 ± 1.85 and -1.69 ± 1.80 diopters, respectively, which were not different from the baseline values. Myopic participants (34 participants), whose spherical equivalent was worse than -0.75 diopters, also did not show any significant refractive change after watching 3D TV. A myopic shift was observed in 31 participants with a mean score of 0.29 ± 0.23 diopters, which resolved after a 10-minute rest.

Conclusions

Watching properly made 3D content on a 3D TV for 50 minutes with a 10-minute intermission at more than 2.8 meters of viewing distance did not affect the refractive error of children.     

Refractive Error in School Children in an Urban and Rural Setting in Cambodia

Purpose: To assess the prevalence of refractive error in schoolchildren aged 12–14 years in urban and rural settings in Cambodia’s Phnom Penh and Kandal provinces.

Methods: Ten schools from Phnom Penh Province and 26 schools from Kandal Province were randomly selected and surveyed in October 2010. Children were examined by teams of Australian and Cambodian optometrists, ophthalmic nurses and ophthalmologists who performed visual acuity (VA) testing and cycloplegic refraction.

Results: A total of 5527 children were included in the study. The prevalence of uncorrected, presenting and best-corrected VA ≤ 6/12 in the better eye were 2.48% (95% confidence interval [CI] 2.02–2.83%), 1.90% (95% CI 1.52–2.24%) and 0.36% (95% CI 0.20–0.52%), respectively; 43 children presented with glasses whilst a total of 315 glasses were dispensed. The total prevalence of refractive error was 6.57% (95% CI 5.91–7.22%), but there was a significant difference between urban (13.7%, 95% CI 12.2–15.2%) and rural (2.5%, 95% CI 2.03–3.07%) schools (P?<?0.0001). Refractive error accounted for 91.2% of visually impaired eyes, cataract for 1.7%, and other causes for 7.1%. Myopia (spherical equivalent ≤ ?0.50 diopters [D] in either eye) was associated with increased age, female gender and urban schooling.

Conclusions: The prevalence of refractive error was significantly higher in urban Phnom Penh schools than rural schools in Kandal Province. The prevalence of refractive error, particularly myopia was relatively low compared to previous reports in Asia. The majority of children did not have appropriate correction with spectacles, highlighting the need for more effective screening and optical intervention.     

Refractive Error Study in Children: results from La Florida, Chile

PURPOSE: To assess the prevalence of refractive errors and vision impairment in school-age children in a suburban area (La Florida) of Santiago, Chile. METHODS: Random selection of geographically defined clusters was used to identify a representative sample of children 5 to 15 years of age. Children in the 26 selected clusters were enumerated through a door-to-door survey and invited to report to a community health clinic for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and examination of the external eye, anterior segment, media, and fundus were done from April through August 1998. Independent replicate examinations of all children with reduced vision and a sample of those with normal vision were done for quality assurance monitoring in six clusters. RESULTS: A total of 6,998 children from 3,830 households were enumerated, and 5,303 children (75.8%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.50 (20/40) or worse in at least one eye was 15.8%, 14.7%, and 7.4%, respectively; 3.3% had best visual acuity 0.50 or worse in both eyes. Refractive error was the cause in 56.3% of the 1,285 eyes with reduced vision, amblyopia in 6.5%, other causes in 4.3%, with unexplained causes in the remaining 32.9%. Myopia -0.50 diopter or less in either eye was present in 3.4% of 5-year-old children, increasing to 19.4% in males and 14.7% in females by age 15. Over this same age range, hyperopia 2.00 diopters or greater decreased from 22.7% to 7.1% in males and from 26.3% to 8.9% in females. Females had a significantly higher risk of hyperopia than males. CONCLUSIONS: Refractive error, associated primarily with myopia, is a major cause of reduced vision in school-age children in La Florida. More than 7% of children could benefit from the provision of proper spectacles. Efforts are needed to make existing programs that provide free spectacles for school children more effective. Further studies are needed to determine whether the upward trend in myopia continues far beyond 15 years of age.     

Refractive Error Study in Children: results from Mechi Zone, Nepal

PURPOSE: To assess the prevalence of refractive error and vision impairment in school age children in the terai area of the Mechi zone in Eastern Nepal. METHODS: Random selection of village-based clusters was used to identify a sample of children 5 to 15 years of age. Children in the 25 selected clusters were enumerated through a door-to-door household survey and invited to village sites for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and anterior segment, media, and fundus examinations were done from May 1998 through July 1998. Independent replicate examinations for quality assurance monitoring took place in all children with reduced vision and in a sample of those with normal vision in seven villages. RESULTS: A total of 5,526 children from 3,724 households were enumerated, and 5,067 children (91.7%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.5 (20/40) or worse in at least one eye was 2.9%, 2.8%, and 1.4%, respectively; 0.4% had best visual acuity 0.5 or worse in both eyes. Refractive error was the cause in 56% of the 200 eyes with reduced uncorrected vision, amblyopia in 9%, other causes in 19%, with unexplained causes in the remaining 16%. Myopia -0.5 diopter or less in either eye or hyperopia 2 diopters or greater was observed in less than 3% of children. Hyperopia risk was associated with female gender and myopia risk with older age. CONCLUSIONS: The prevalence of reduced vision is very low in school-age children in Nepal, most of it because of correctable refractive error. Further studies are needed to determine whether the prevalence of myopia will be higher for more recent birth cohorts.     

Refractive Error Study in Children: sampling and measurement methods for a multi-country survey

PURPOSE:The Refractive Error Study in Children was designed to assess the prevalence of refractive error and vision impairment in children of different ethnic origins and cultural settings. METHODS: Population-based cross-sectional samples of children 5 to 15 years of age were obtained through cluster sampling. Presenting, uncorrected, and best-corrected visual acuity, along with refractive error under cycloplegia, were the main outcome measures. Amblyopia and other causes of uncorrectable vision impairment were determined. RESULTS: Study design and sample size calculations, survey enumeration and ophthalmic examination methods, quality assurance monitoring, and da ta analyses and statistical methods are described. CONCLUSIONS: The study design, sample size, and measurement methods ensure that the prevalence of age-specific and sex-specific refractive error can be estimated with reasonable accuracy in the target populations. With commonality of methods, a comparison of findings between studies in different ethnic origins and cultural settings is possible.     

Strabismus,Visual Acuity,and Uncorrected Refractive Error in Portuguese Children Aged 6 to 11 Years

Introduction: Visual anomalies that affect school-age children represent an important public health problem. Data on the prevalence are lacking in Portugal but is needed for planning vision services. This study was conducted to determine the prevalence of strabismus, decreased visual acuity, and uncorrected refractive error in Portuguese children aged 6 to 11 years.

Methods and materials: A cross-sectional study was carried out on a sample of 672 school-age children (7.69?±?1.19 years). Children received an orthoptic assessment (visual acuity, ocular alignment, and ocular movements) and non-cycloplegic autorefraction.

Results: After orthoptic assessment, 13.8% of children were considered abnormal (n?=?93). Manifest strabismus was found in 4% of the children. Rates of esotropia (2.1%) were slightly higher than exotropia (1.8%). Strabismus rates were not statistically significant different per sex (p?=?0.681) and grade (p?=?0.228). Decreased visual acuity at distance was present in 11.3% of children. Visual acuity ≤20/66 (0.5 logMAR) was found in 1.3% of the children. We also found that 10.3% of children had an uncorrected refractive error.

Conclusions: Strabismus affects a small proportion of the Portuguese school-age children. Decreased visual acuity and uncorrected refractive error affected a significant proportion of school-age children. New policies need to be developed to address this public health problem.     

放射状角膜切开术后屈光不正的早期改变

59例118只眼行放射状角膜切开术后屈光不正的早期改变进行分析。全部病例术前由专一验光师用睫状肌麻痹剂扩瞳检影验光，并根据其屈光不正情况将其分成轻、中、重度近视及复性近视散光4组。在术后第2周、3个月及9个月时分别再用同一方法验光。发现轻、中度近视组术后裸眼视力均明显提高，近视度明显减少，其屈光度变化在0．25～1．75D之间且保持较稳定状态；高度近视组在1．50～6．25D之间；复性近视散光组在0．50～2．50DCA之间；后两组且不稳定。     

Myopic and Hyperopic Refractive Error in Adults: An Overview

This article provides an overview of the recent epidemiologic findings on myopic and hyperopic refractive error in adults. Refractive errors are common conditions with high costs associated with their correction and a cause of public health and economic concerns. Myopia and hyperopia, the most common types of refractive error, are complex multifactorial conditions with prevalences that vary across populations of different ancestral origins. Recent studies have demonstrated consistently that longitudinal changes in refractive error occur and may be part of an aging process. A cohort effect also has been demonstrated in some populations, indicating that observed changes may be due to both longitudinal changes and changes across birth cohorts. The increase in myopia at older ages appears to be due to associations with other ocular conditions such as cataract. This overview highlights major findings from recent population-based studies of persons 40 years and older on 1) the importance of uncorrected refractive error as a cause of visual impairment and 2) the epidemiology of myopic and hyperopic refractive error, regarding their prevalence, changes over time and longitudinally and associated factors. Suggestions for future directions and opportunities to advance the understanding of the epidemiology of refractive errors in adults are offered.