Refractive errors and cataract as causes of visual impairment in Brazil

Purpose To identify the main causes of visual impairment (VA = 0.2) within the population over 50 years of age examined in “Cataract Free Zone” projects sponsored by the University of Campinas from 1986 to 1995. Methods A retrospective review of the ophthalmic forms used for 60,404 patients examined in 74 Cataract Projects was performed. Through mass media information, adults of the target region or city were asked to self-test their vision. Patients with VA = 0.2 in the better eye were to come to a visual acuity test. Using Snellen charts, visual acuity testing was done by trained auxiliaries and medical students. The positive cases were then examined by ophthalmologists Criteria were established for the classification of the diagnoses and statistical analysis was performed. Results After the self-test of visual acuity, 60,404 patients came to have their visual acuity tested; 11,462 (18.97%) cases were considered positive and were submitted to complete eye examination; 5447 (42.7%) received spectacles for vision improvement, and 2704 (23.59%) had cataract surgery done. Other important causes of visual impairment were senile macular degeneration (5.4%) and glaucoma (4.02%). Conclusion The main causes of visual impairment were non-corrected refractive errors and senile cataract. Ophthalmic community-based campaigns to serve the older population are recommended in order to detect and treat the identified cases and to indicate possible changes in the health care system.     

Prevalence of visual impairment and estimation of refractive errors among school children in Kakamega, Kenya

AIM: To investigate the prevalence of visual impairment (VI) and provide an estimation of uncorrected refractive errors in school-aged children, conducted by optometry students as a community service. METHODS: The study was cross-sectional. Totally 3343 participants were included in the study. The initial examination involved assessing the uncorrected distance visual acuity (UDVA) and visual acuity (VA) while using a +2.00 D lens. The inclusion criteria for a subsequent comprehensive cycloplegic eye examination, performed by an optometrist, were as follows: a UDVA<0.6 decimal (0.20 logMAR) and/or a VA with +2.00 D ≥0.8 decimal (0.96 logMAR). RESULTS: The sample had a mean age of 10.92±2.13y (range 4 to 17y), and 51.3% of the children were female (n=1715). The majority of the children (89.7%) fell within the age range of 8 to 14y. Among the ethnic groups, the highest representation was from the Luhya group (60.6%) followed by Luo (20.4%). Mean logMAR UDVA choosing the best eye for each student was 0.29±0.17 (range 1.70 to 0.22). Out of the total, 246 participants (7.4%) had a full eye examination. The estimated prevalence of myopia (defined as spherical equivalent ≤-0.5 D) was found to be 1.45% of the total sample. While around 0.18% of the total sample had hyperopia value exceeding +1.75 D. Refractive astigmatism (cil<-0.75 D) was found in 0.21% (7/3343) of the children. The VI prevalence was 1.26% of the total sample. Among our cases of VI, 76.2% could be attributed to uncorrected refractive error. Amblyopia was detected in 0.66% (22/3343) of the screened children. There was no statistically significant correlation observed between age or gender and refractive values. CONCLUSION: The primary cause of VI is determined to be uncorrected refractive errors, with myopia being the most prevalent refractive error observed. These findings underscore the significance of early identification and correction of refractive errors in school-aged children as a means to alleviate the impact of VI.     

2010年上海市宝山区小学生屈光不正和视力损伤的患病率调查

背景 流行病学调查表明,青少年视力损伤是一个全球性的公共卫生问题,其首要原因是未矫正的屈光不正,因此一定规模的流行病学调查对儿童屈光不正的矫正具有重要意义.目前尚缺乏上海市大规模儿童视力损伤和屈光不正的流行病学调查资料. 目的 调查上海市6 ～12岁小学生视力损伤与屈光不正的患病情况.方法 采用横断面调查研究设计,于2010年5月至2011年4月分层随机整群抽取上海市宝山区6所学校的4 686名小学生进行研究,眼部检查包括视力、外眼、眼前节、屈光间质、眼底和眼压检查,并记录睫状肌麻痹后电脑验光的结果和眼位.结果 实际受检学生4 594人,应答率为98.0％,接受睫状肌麻痹后验光者3 975人,占84.8％.双眼裸眼视力≤0.5者占14.4％（662/4 594）,其中343人配戴眼镜,占51.8％.所有受检者中,任一眼裸眼视力≤0.5者1 031人,占22.4％.受检的视力损伤者中屈光不正占96.9％（999/1 031）,弱视占3.6％（37/1 031）.接受睫状肌麻痹后验光的小学生中,近视、远视和散光的患病率分别为31.1％、4.3％和33.0％.公办学校的小学生近视患病率高于外来务工随迁子女学校的学生,差异有统计学意义（x2=5.46,P=0.02）.Logistic回归分析显示,年龄和女生与近视的发生及发展明显有关（年龄：OR=1.60,95％ CI：1.53 ～ 1.68,P＜0.01;女生：OR=1.33,95％CI：1.16～1.54,P＜0.01）. 结论 中国上海市小学生视力损害的主要原因是近视,应注意筛查并提高小学生屈光不正的矫正覆盖率.     

高中学生眼屈光状态相关因素的等级回归分析

目的探讨影响眼屈光状态的主要因素。方法以某中学高中部高一至高三的219名学生为研究对象,分问卷调查和眼生物测量两个部分。问卷调查内容包括年龄、性别、年级、民族、遗传背景、是否主动休息、目本距离、每天学习时间、每天玩电脑时间等。眼生物学测量包括：角膜屈折力CD（cornea diopter）、前房深度AC（anterior chamber depth）、晶状体厚度LENS（lens thickness）、玻璃体腔深度VITR（vitreous depth）、眼轴长度AL（ocular axis longitude）等。将所有可能的因素同时纳入研究,应用逐步等级回归方法,依次排除相关性不大的因素。结果完成全部体检项目的共有182名,占全部学生的83.5%;与眼屈光不正发生最为紧密的相关因素有：年龄、性别、平均角膜屈率、前房深度、晶状体厚度和玻璃体深度等因素。各等级累积概率的回归方程分别是：Link远视概率=61.012-（0.199×年龄＋0.813×性别取值＋0.581×平均角膜屈率＋1.076×前房深度＋1.953×晶状体厚度＋1.643×玻璃体深度）;Link正视累积概率=65.396-（0.199×年龄＋0.813×性别取值＋0.581×平均角膜屈率＋1.076×前房深度＋1.953×晶状体厚度＋1.643×玻璃体深度）;Link低度近视累积概率=67.957-（0.199×年龄＋0.813×性别取值＋0.581×平均角膜屈率＋1.076×前房深度＋1.953×晶状体厚度＋1.643×玻璃体深度）;Link中度近视累积概率=70.370-（0.199×年龄＋0.813×性别取值＋0.581×平均角膜屈率＋1.076×前房深度＋1.953×晶状体厚度＋1.643×玻璃体深度）。根据频数分布表,求得预测准确率为68.68%。结论用年龄、性别、平均角膜屈率、前房深度、晶状体厚度和玻璃体腔深度等6个因素来预测眼的屈光状态,其准确率将近70%,因而这6个因素是决定眼屈光状态的主要因素。     

天津市视障学校学生视觉损害的病因及康复现状

目的：调查天津市视障学校学生视觉损害的分级及病因,分析不同类型助视器的康复效果,为儿童视觉损害的康复工作提供指导依据。

方法：于2019-08/09纳入天津市视力障碍学校学生86例。通过视力、屈光及眼部检查等方法,评估学生视觉损害的分级及主要病因。对盲和低视力学生分别验配3种远用及近用助视器,分析其康复效果。

结果：学生86例中盲49例,低视力37例,主要病因为先天性眼球发育不良26例(30%)。盲和低视力学生应用助视器后康复远视力均有所提升(F=110.59,P<0.01),低视力组远视力优于盲目组(F=184.06,P<0.01)。盲目组应用3种远用助视器脱残率及低视力组脱残率均无差异,3种近用助视器阅读成功率在盲目组无差异,低视力组电子助视器优于手持放大镜及眼镜式助视器(χ²=7.974、10.571,均P<0.01)。

结论：儿童视觉损害以先天性眼病为主,验配合适的助视器可提高其康复效果,低视力患者电子助视器康复效果优于手持放大镜及眼镜式助视器。     

Prevalence and causes of blindness and visual impairment among school children in south-western Nigeria

The aim of the study was to assess the prevalence and identify the causes of blindness and visual impairment in school children of Ilesa-East Local Government Area of Osun State, Nigeria. A total of 1144 school children in primary and secondary schools were selected using a 2-stage random sampling method and examined to determine the prevalence and causes of blindness and visual impairment. A total of 17 (1.48%) children were blind or visually impaired. These comprised of 11 (0.96%) children who were visually impaired and 4 (0.3%) who were severely visually impaired. Only 2 (0.15%) school children were blind. The causes of visual impairment were refractive error 10 (0.87%) and immature cataract 1 (0.08%), causes of severe visual impairment included corneal opacities 2 (0.2%), amblyopia leading to squint 1 (0.08%) and 1 cataract 1 (0.08%). The causes of blindness in school children were corneal scars presumed to be due to vitamin A deficiency 1 (0.08%) and keratoconus 1 (0.08%). Causes of blindness and visual impairment in children attending regular schools in Nigeria were treatable. Prevention, early recognition and prompt treatment of these diseases by regular screening of school children would definitely reduce unnecessary visual handicap in Nigerian school children so that they can attain their full potential in the course of their education. Also, information from this study is relevant for the purpose of planning eye care programmes for the prevention of blindness in Nigerian school children. This will go a long way in the prevention of unnecessary blindness and visual impairment in school children.     

年龄对屈光不正性弱视儿童图形视觉诱发电位的影响

目的 分析屈光不正性弱视儿童图形视觉诱发电位（PVEP）检测结果的特点及年龄对其的影响.方法 回顾性系列病例研究.等效球镜为远视的屈光不正性弱视患儿92例（184眼）,按最佳矫正视力0.8～0.6、0.5～0.2、≤0.1三个级别分为轻度弱视组108眼,中度弱视组65眼,重度弱视组11眼.每组又以6岁为界进行分组,分为＜6岁组和≥6岁组.采用视觉电生理检查系统检测PVEP,对弱视组间差异行单因素方差分析,同一程度弱视组中的不同年龄组间行独立样本t检验,比较不同弱视程度组间及不同年龄组间P100波潜伏期（LP100）及振幅（AP100）的差异.结果 随弱视程度加重,PVEP的LP100延长,三组间差异有统计学意义（F=151.30,P＜0.01）,两两间差异均有统计学意义（P＜0.01）.三组间AP100差异有统计学意义（F=13.59,P＜0.05）,两两比较示,重度组的AP100明显较其余两组低,差异有统计学意义（P＜0.01）,中度组较轻度组低,但差异无统计学意义.轻度组中,年龄≥6岁组与＜6岁组比较,LP100明显延长,AP100降低,差异有统计学意义（t=5.08、7.45,P＜0.01）;中度组也呈类似表现（t=4.68、4.27,P＜0.01）;重度组结果类似,但由于例数少,未进行统计分析.结论 PVEP的LP100、AP100可作为衡量儿童屈光不正性弱视严重程度的客观指标,同时对结果进行分析时应充分考虑年龄的影响.     

Status of eye health among tribal school children in South India

Purpose:Global trends show a high prevalence of refractive errors among children. The prevalence of vision impairment due to uncorrected refractive errors among school children is increasing and the need for management of other ocular conditions is also reported. This study presents the status of eye health and pattern of daily activities among the school children of a tribal location in Tamil Nadu, South India.Methods:A cross-sectional study was conducted in 13 schools of Karumandurai cluster, Salem district in Tamil Nadu, India. A three-phased comprehensive school screening protocol was conducted to understand the prevalence of vision impairment, refractive error, and other ocular conditions along with a survey about the daily activities of the children at school and home.Results:Among the 3655 children screened, the prevalence of vision impairment was found to be 0.62% (n = 23, 95% confidence interval [CI] 0.42–0.94) and prevalence of refractive error was 0.30% (n = 11, 95%CI 0.17–0.54), among which 0.11% (n = 4) were already wearing spectacles. A total of 44 children (1.20%; 95%CI 0.90–1.61) were found to have other ocular problems and among them, 14 (0.38%) had visual acuity less than 20/30 (6/9). Almost 84% of children required surgical or specialty eye care services. Vision impairment was more in children with other ocular conditions compared to refractive errors (P < 0.001).Conclusion:The prevalence of vision impairment and refractive errors in this tribal area was less. Ocular conditions were more prevalent than refractive errors in this tribal region with the majority of children needing specialty or surgical eye care services. This implies the need for access to secondary or tertiary eye care centers.     

Screening for visual impairment: outcome among schoolchildren in a rural area of Delhi

Background:

Uncorrected refractive errors are the main cause of vision impairment in school-aged children. The current study focuses on the effectiveness of school eye screening in correcting refractive errors.

Objectives:

1. To study the magnitude of visual impairment among school children. 2. To assess the compliance of students for refraction testing, procurement and use of spectacles.

Materials and Methods:

An intervention study was conducted in schools of the north- west district of Delhi, in the rural field practice area of a medical college. Students studying in five government schools in the field practice area were chosen as the study subjects.

Results:

Out of 1123 students enrolled, 1075 (95.7%) students were screened for refractive errors. Low vision (visual acuity < 20/60) in the better eye was observed in 31 (2.9%) children and blindness (visual acuity <20/200) in 10 (0.9%) children. Compliance with referral for refraction was very low as only 51 (41.5%) out of 123 students could be tested for refraction. Out of 48 students, 34 (70.8%) procured spectacles from family resources but its regular use was found among only 10 (29.4%) students. The poor compliance among students stems out of various myths and perceptions regarding use of spectacles prevalent in the community.

Conclusion:

Refractive error is an important cause of avoidable blindness among rural school children. Behavior change communication among rural masses by spreading awareness about eye health and conducting operational research at school and community level to involve parent''s teachers associations and senior students to motivate students for use of spectacles may improve utilization of existing eye health services in rural areas.     

吉林省视力残疾和弱视现状分析

目的 调查分析吉林省视力残疾、弱视、屈光不正等的现状及流行病学的一般情况。方法在吉林省采用概率比例随机抽取100个样本单位（51139人），占全省总人数的2．29％，专项调查长春市8所小学8861人（17722眼），并重点对其低视力构成、弱视患病情况进行统计学分析。结果全部调查的51139人中58％的视力残疾需要医院治疗，75％为可防可治者。调查的小学8861人中，弱视占调查人数的1．84％，以眼数计算占1．28％，是视力不良的第2位。结论调查吉林省视力残疾、弱视、屈光不正现状，掌握吉林省视力残疾，特别是弱视、屈光不正患病情况及流行病学等资料，为政府行政主管部门制定政策特别是卫生和教育主管部门制定相应的条例或法规提供可靠的基础依据（中国眼耳鼻喉科杂志，2008，8：377—378）     

双目屈光筛查仪在4~5岁学龄前儿童视力筛查中的应用研究

目的评估双目屈光筛查仪在4~5岁学龄前儿童视力筛查中判定屈光性弱视危险因素(ARF)的精确度。方法横断面研究。于2016年9至12月在南京市雨花台区对4~5岁学龄前儿童使用双目屈光筛查仪进行非散瞳屈光度数筛查及综合性眼科检查。对其中疑似眼部异常儿童及主动接受详细检查的儿童进行睫状肌麻痹检影验光(CR)检查,采用Wilcoxon符号秩检验比较双目屈光筛查仪与CR检查屈光度数的差异,并用Bland-Altman法评估二者的一致性。参照美国斜视与小儿眼科学会(AAPOS)2013年发布筛查指南中的标准,以CR检查结果判定受试儿童是否具有屈光性ARF,并以此为金标准,评估双目屈光筛查仪以5种常用转诊标准(敏感性标准、Matta/Silbert标准、AAPOS2013标准、阿拉斯加州盲童探索组织2012标准、特异性标准)判定受试儿童屈光性ARF的准确度。采用受试者工作特征(ROC)曲线计算双目屈光筛查仪判定屈光性ARF的最佳截断值作为最佳转诊标准。结果共有1986名儿童行双目屈光筛查仪检查,年龄(4.57±0.29)岁,包括1084名男童和902名女童。双目屈光筛查仪的检查成功率为99.04%(1967/1986)。共有1892名儿童双目屈光筛查仪检查取得了检测数值,其中1827名(96.56%)儿童可在3次检测内获得可信结果。共有538名儿童接受了CR检查,除外1名被双目屈光筛查仪直接识别为远视的儿童后,剩余537名儿童进行了屈光度数对比分析,结果显示双目屈光筛查仪较CR低估球镜度数[0.75(0.50,1.25)D与1.25(1.00,1.75)D比较;Z=-10.36,P<0.01],高估柱镜度数[-0.50(-0.75,-0.25)D与-0.25(-0.75,0.00)D比较;Z=-11.10,P<0.01],低估等效球镜度数[0.63(0.38,0.88)D与1.00(0.75,1.50)D比较,Z=-13.33,P<0.01]。一致性分析显示,分别有96.28%(517/537)、95.34%(512/537)、96.65%(519/537)儿童的双目屈光筛查仪及CR检测值在球镜度数、柱镜度数、等效球镜度数的95%一致性界限内。CR检查结果显示47名儿童(8.74%)具有屈光性ARF,以此为金标准,双目屈光筛查仪以5种常用转诊标准判定屈光性ARF的敏感度为63.83%~97.87%,特异度为53.36%~97.56%,约登指数为0.51~0.80,阳性预测值为16.73%~74.51%,阴性预测值96.57%~99.62%。ROC曲线计算得出双目屈光筛查仪判定散光性ARF的最佳转诊标准为散光度数>1.38 D。结论双目屈光筛查仪在4~5岁学龄前儿童视力筛查中判定屈光性ARF的精确度较高。     

北京市40岁以上部分人群屈光矫正前后视力损害分析

目的 :分析北京市特定地区 4 0岁以上人群中屈光矫正前后的视力损害情况。方法 :2 0 0 1年我们对北京市内干休所所在的社区 4 0岁以上人群共 2 4 71人和北京北部榆垡镇三个生产大队 4 0岁以上人群共 1980人进行了盲和低视力的流行病学调查。视力损害分别按照WHO和欧美等一些国家的标准进行分析。同时也分析了与可矫正的视力损害有关的人群特征及矫正前后视力损害的病因。结果 :按WHO标准划分 ,城市中有 10 .2 0 % (2 5 2 / 2 4 71)受检者为可矫正的视力损害 ,有 0 .32 % (8/ 2 4 71)为不可矫正的视力损害 ;农村中有 3.89% (77/ 1980 )者为可矫正的视力损害 ,0 .76 %(15 / 1980 )为不可矫正的视力损害。按USA标准划分 ,城市中有 14 .4 1% (35 6 / 2 4 71)受检者为可矫正的视力损害 ,有 0 .5 7% (14 / 2 4 71)为不可矫正的视力损害 ;农村中有 7.73%(15 3/ 1980 )为可矫正的视力损害 ,1.6 7% (33/ 1980 )为不可矫正的视力损害。年龄是影响可矫正视力损害的最重要的因素。结论 :屈光不正是老年人视力损害的重要因素 ,通过矫正可使相当一部分人脱离视力损害的范围 ,说明了屈光不正的矫正在老年人生活中的重要性。     

Uncorrected refractive errors are important causes of avoidable visual impairment in Hungary: re-evaluation of two existing national data sets

AIM: To review existing data for the prevalence of corrected, uncorrected, and inadequately corrected refractive errors and spectacle wear in Hungary.METHODS: Data from two nationwide cross-sectional studies were analysed. The Rapid Assessment of Avoidable Blindness study collected population-based representative national data on the prevalence of visual impairment due to uncorrected refractive errors and spectacle coverage in 3523 people aged ≥50y (Group I). The Comprehensive Health Test Program of Hungary provided data on the use of spectacles in 80 290 people aged ≥18y (Group II).RESULTS: In Group I, almost half of the survey population showed refractive errors for distant vision, about 10% of which were uncorrected (3.2% of all male participants and 5.0% of females). The distance spectacle coverage was 90.7% (91.9% in males; 90.2% in females). The proportion of inadequate distance spectacles was found to be 33.1%. Uncorrected presbyopia was found in 15.7% of participants. In all age groups (Group II), 65.4% of females and 56.0% of males used distance spectacles, and approximately 28.9% of these spectacles were found to be inappropriate for dioptric power (with 0.5 dioptres or more). The prevalence of inaccurate distance spectacles was significantly higher in older age groups (71y and above) in both sexes.CONCLUSION: According to this population-based data, uncorrected refractive errors are not rare in Hungary. Despite recent national initiatives, further steps are required to reduce uncorrected refractive errors and associated negative effects on vision, such as avoidable visual impairment.     

Prevalence of visual impairment and refractive errors in an urban area of Mexico

AIM: To determine the distribution of refractive errors in a school-age population in Quintana Roo (Mexico) in the framework of an international cooperation campaign for the prevention of blindness. METHODS: A sample of 2647 school-age children (ranging from 5 to 14 years old) with a mean age of 9.1±1.9 years old were tested by trained volunteers for distance visual acuity (VA) and refractive errors. The first screening examination included uncorrected distance visual acuity (UDVA) and VA with a +2.00 D lens. Inclusion criteria for a second complete cycloplegic eye examination performed by an optometrist were UDVA <20/25 (0.10 logMAR or 0.8 decimal) and/or VA with +2.00 D ≥20/25. RESULTS: A total of 633 (23.9%) children underwent the second complete eye examination. Mean logMAR UDVA was 0.035±0.094 (range 1.00 to 0.00 logMAR) for the right eyes and 0.036±0.160 (range 1.00 to 0.00 logMAR) for the left eyes. Bilateral amblyopia was found in 17 children (2.7% of refracted eyes; 0.64% of the total). The main reason for visual impairment (VI) in the sample analyzed was found to be refractive errors. In 12 children (1.9% of refracted eyes; 0.45% of the total) the VI was bilateral and 9 (1.4% of refracted eyes; 0.34% of the total) achieved a corrected distance visual acuity of 20/25 or better in both eyes. Mean magnitude of sphere and refractive cylinder was +0.20±0.96 D and -0.43±0.85 D in right eyes, and +0.24±1.08 and -0.43±0.83 D in left eyes. The proportion of myopic eyes [standard equivalent (SE) ≤-0.50 D] was 4.6% of the whole sample (5290 eyes). The mean magnitude of myopia was -0.84±3.44 D for the right eyes and -0.82±5.21 D for the left eyes. The proportion of hyperopic patients (SE≥+2.00 D) was 2.4% (15/633), which corresponded to 0.60% of the whole sample (32/5290 eyes). No statistically significant correlation of age to manifest sphere or cylinder was found. CONCLUSION: VI due to uncorrected refractive errors can be easily corrected with glasses but it is still a burden to be treated. Myopia is prevalent in this sample. More efforts towards correcting uncorrected refractive errors are needed.     

Prevalence and causes of visual impairment and blindness in the South Western region of Saudi Arabia

A population-based survey of the prevalence of major causes of blindness and visual impairment was conducted in Bisha region, Saudi Arabia. Overall, 2882 people were examined. The prevalence of blindness (visual acuity of < 3/60 in the better eye with best available correction) was 0.7% and the prevalence of visual impairment (visual acuity < 6/12 but 3/60 in the better eye with best available correction) was 10.9%. Cataracts were responsible for 52.6% of blindness and 20.6% of visual impairment. Refractive errors accounted for 67.9% of visual impairment. Proper management of cataracts and correction of refractive errors will cure 73.6% of blind subjects and 88.5% of visually handicap people in this part of the world.     

左旋多巴对屈光参差性弱视患儿视力的影响

目的：观察息宁（左旋多巴／卡比多巴）对难治性屈光参差性弱视患儿视力的影响,探讨左旋多巴用药时间和治疗机理。方法：给３２例（５￣１５岁）经传统疗法治疗至少６个月无效的屈光参差性弱视患儿口服息宁１ｍｇ／０．２５ｍｇ／ｋｇ,一日三次,连续６０天。观察服药前及服药后第３、６、９、３０、６０天单字Ｅ视力的变化。结果：弱视眼和优势眼的单字视力服药后第３天提高,差异有极显著性（Ｐ〈０．０１）,继续服药无进一步改