The Optometric Management of the Child with Low Vision

ABSTRACT In recent years, optometrists have taken a greater interest in paediatric optometry, yet the optometric management of the child with low vision has received little attention. Optometrists have the fundamental training, clinical expertise and attitudes to manage the paediatric low vision patient effectively. Although visually handicapped children receive specialist medical care from birth or at a very early age, referral to other low vision services frequently does not occur until the child enters the education system. Optometrists in private practice can bridge the gap between medicine and education and improve the quality of paediatric low vision care by understanding the rationale for improvement of efficiency in visual functioning and developing a sincere commitment to extending their involvement with these children beyond the provision of low vision aids.     

The measurement of visual acuity in children: an evidence‐based update

Over the past decade, a number of large clinical trials have provided important information relating to the reliability and repeatability of commonly used paediatric tests of vision and their role in the diagnosis and management of paediatric ocular diseases. The aim of this review is to summarise recent findings on the use of paediatric visual acuity tests in clinical practice and to discuss the validity and accuracy of visual acuity measurements in infants and young children. We provide a broad overview of the benefits and challenges of measuring visual acuity in children and then discuss age‐appropriate tests for measuring visual acuity in infants through to school‐age children. We also discuss normative values for visual acuity in each age group and, where possible, provide comparisons of results between tests with a particular focus on the importance of optotype design.     

Reading performance in children with low vision

Purpose: While educators and optometrists are concerned with reading efficiency in children with low vision, in most low vision assessments, children's reading performance is assessed only by a brief evaluation of reading fluency. We examined the relationships between clinical vision measures and reading performance in children with low vision. Methods: Subjects were 71 students with low vision, aged seven to 18 years. The vision and reading performance measures were: high contrast distance visual acuity, contrast sensitivity using both the Pelli‐Robson and LH symbol charts, near text visual acuity and reading rates on a range of print sizes. Results: Most children achieved maximum reading rate at print sizes between 2.5 and seven times larger than threshold print size. Maximum reading rate increased significantly with age and near visual acuity. There was no significant relationship between reading rate and contrast sensitivity. Conclusions: The majority of children with low vision can achieve near normal reading rates with magnification. Age is the strongest predictor of reading rate in children with low vision. They need print sizes well above threshold to achieve maximum reading rate. Routine contrast sensitivity testing of visually impaired students is not indicated for reading assessment.     

儿童盲和低视力的病因与屈光状态及远用助视器康复研究

目的：分析儿童盲和低视力的病因、屈光状态、屈光矫正和配用光学远用助视器矫正后的视力情况。

方法：选取2015-12/2018-04我科门诊接诊及盲校筛查的6～16岁低视力儿童和盲童212例422眼,通过相关检查明确病因和屈光状态,对部分患儿进行屈光矫正和光学远用助视器验配矫正,分析矫正后视力情况。

结果：儿童盲和低视力病因以先天性和遗传性眼病为主,本组病例中先天性白内障是首位原因(19.3%),低视力屈光不正以轻中度远视和近视多见(65.3%),屈光矫正后脱盲率(26.4%)和脱残率(14.6%)均低于联合远用助视器验配矫正后的脱盲率(58.3%)和脱残率(91.1%),差异均有统计学意义(P<0.01)。

结论：儿童盲和低视力病因复杂,应加强预防和筛查工作,低视力儿童应常规进行屈光矫正并配合使用远用助视器矫正,以利获得满意的康复效果。     

北京市医疗机构低视力康复服务状况调查

目的 了解北京市医疗机构低视力康复服务能力及现状,为政府低视力康复工作提供政策依据。设计 横断面研究。研究对象 北京市二级及以上医院90家。方法 通过问卷形式对90家医疗机构低视力康复工作进行调查,调查问卷由各调查机构视光和眼科负责人填写。收集的资料进行统计分析。主要指标 问卷应答率、是否开展低视力服务、不能开展低视力服务的原因、低视力康复年服务量、种类、人员状况及助视器的种类。结果 90家医疗机构中,做出有效应答的医疗机构86家,应答率95.56%。可提供低视力康复服务的医疗机构6家（6.98%）。医疗机构未开展低视力康复服务的原因依次是缺乏基本设备和助视器、缺乏资金、缺乏低视力专业人员以及没有患者来源。各家医疗机构提供的年服务量少者为0~49例,多者大于250例,年总服务量不足600人。低视力工作人员仅有19位。6家医院可提供光学近用助视器,3家医院可提供光学远用助视器,2家医院可提供电子助视器,6家医院均不能提供非视觉助视器,均未开展儿童功能性视力康复训练、日常生活能力和技能康复训练、职业训练、适应及行走训练等康复服务。购买助视器的资金来源有患者自费或非政府机构的资金支持,各种助视器的支付均未纳入医保范围。结论 北京市医疗机构低视力康复服务能力远远不能满足低视力患者的需求,应加强北京市低视力康复服务能力。（眼科, 2015, 24： 348-351）     

Reading errors made by children with low vision.

Previous research has shown that, on average, children with low vision lag their sighted peers in general reading development (in terms of speed, accuracy and comprehension). This study sought to examine this apparent lag by comparing the reading profiles of 25 normally sighted readers (mean age 8 years 8 months) with 25 low vision readers. The children were tested using a reading test (the Neale Analysis of Reading Ability, NARA) and were matched on the reading accuracy score produced by the test. Therefore in terms of the reading accuracy scores (and reading ages) derived from the NARA both groups were the same. The low vision readers were on average older than the normally sighted children (mean = 10 years, 5 months). When the reading profile (i.e. accuracy, comprehension and speed) was examined in the same analysis no significant effect was revealed [d.f. = 1, 48; F = 0.05; p > 0.1], but a general lag for these children is suggested (in keeping with previous research). However, a closer analysis of the reading error profile revealed the most common reading errors made by all readers in the analysis were either mispronunciations or substitutions. The low vision readers were more prone to making substitution errors than mispronunciations and the reverse was true for normally sighted readers [d.f. = 1, 48; F = 7.1; p < 0.05]. This indicates that the reading strategies adopted by low vision readers may differ from those of normally sighted readers of the same apparent reading ability.     

矫正屈光不正对儿童低视力康复的意义

目的 探讨有屈光不正的低视力儿童戴矫正眼镜后对应用助视器提高视的效果。方法 经散瞳验光 后视力有提高或改善者,予以配镜。然后再应用远用双筒与单筒望镜式助视器。结果 ３５０例中有９００例（占２５％）经验光配镜后视力均有一定程度的提高与改善,在这９０例中不戴镜直接用助视器时,其脱残率（视力提高到０．３以上）为５４．４％,而在戴镜基础上再应用助视器,则脱残率为８３．３％,两者之间差异有着非常显著性意义（     

A review of paediatric vision screening protocols and guidelines

Vision screening plays an important role in the early detection of children who have or probably are predisposed to have specific visual problems. The validity and reliability of the screening batteries in relation to the age group to be screened, and the person administering the test as well as the referral and follow-up criteria contribute to the overall outcome of the vision screening. Despite the long history of vision screening and significant improvement in the development of screening protocols, no agreement exists concerning the age at which children should be screened, the exact test batteries that should be included and who should conduct the screening. This review highlights some important aspects of the history of paediatric vision screening and available evidence in support of their use to detect visual conditions in children. It also examines some of the barriers against the development of paediatric vision screening models especially in low and medium income countries.     

Profile of a low vision clinic population

Background : Causes of low vision and types of low vision devices (LVDs) prescribed in other low vision clinics have been studied extensively. Similar studies have not been conducted in Malaysia. This paper reports the results of a retrospective study of 573 patients seen at the Universiti Kebangsaan Malaysia-Malaysian Association for the Blind (UKM-MAB) low vision clinic in Kuala Lumpur. Methods : The record cards of 573 patients seen at the UKM-MAB clinic over 10 years were examined and the following information extracted: date of first consultation, age, sex, cause of visual impairment as diagnosed by an ophthalmologist and types of low vision devices (LVDs) prescribed. Results : The majority of patients were from the younger age groups with 423 (73.8 per cent) less than 50 years of age. Three hundred and ninety-five (68.9 per cent) of the subjects were males and 178 (31.1 per cent) female. The main causes of low vision were congenital structural defects including nystagmus among patients in the zero to 29 years age group, retinitis pigmentosa among the 30 to 59 years age group and age-related macular degeneration (ARM) among those over 60 years of age.     

低视力康复现状与进展

低视力康复主要是通过助视器的使用配合低视力康复训练。本研究通过对成人和儿童低视力康复现状、低视力功能状态评价、助视器研究发展方向进行综述，为低视力患者和康复工作提供一定指导。运用现有的助视器，老年及儿童低视力患者的视力康复取得了较好的效果。新型助视器的研制和开发，为低视力患者的康复迈进了一步。     

视觉训练对低视力儿童阅读速度的影响

目的评价视觉训练对已有助视器的低视力儿童阅读速度的影响。方法共有9位有助视器使用经验的低视力儿童,先测量其阅读速度,再进行一系列的视觉训练和阅读训练,2个月后,当他们完成训练时,再次测量对相同文章的阅读速度,并比较训练前后患儿阅读速度的变化。结果在训练前后患儿阅读四号字的速度差异有显著性(P=0.003);在训练前后患儿阅读小五号字的速度差异有显著性(P=0.002)。结论视觉训练和阅读训练对提高低视力儿童的阅读速度是有效的,在临床低视力康复工作中,我们不应仅仅只把助视器提供给低视力儿童,同时还应进行适当的视觉训练和阅读训练来提高患儿的阅读速度,这对于正在学习阶段的儿童尤为重要。     

助视器在低视力儿童中的应用

目的探讨自行来院就诊低视力儿童的病因及低视力康复疗效,方法对门诊筛查视力低常儿童进行散瞳验光、眼底等检查,诊断为低视力者,应用远用、近用助视器进行视力康复训练;结果在25例低视力儿童中,(1)病因以先天性眼球震颤合并屈光不正多见,占76.00%;(2)20例选择康复远视力,最佳矫正远视力在0.1～<0.3,用4X、6X单筒近距远距观察镜康复远视力达到≥1.0,脱残率100%;(3)5例选择康复近视力,最佳矫正近视力<0.3~0.1,经过使用2.5X、3X、4X直柄放大镜和2.5X木马放大镜康复近视力≥0.5,近视力康复有效率100%。结论应用助视器能有效提高低视力儿童的远、近视力和视觉质量,让患儿有机会具备接受正常教育的用眼条件,因此,早发现、早诊断、早矫正、早康复,对低视力儿童的身心健康、拓宽知识领域、升学、就业具有积极地意义。     

中国大陆三级医疗机构低视力服务专业人员配置和服务提供情况分析

目的：统计分析我国三级医疗机构低视力服务专业人员配置和服务提供情况，为进一步推进我国低视力医疗康复工作提供参考依据。方法：描述性研究。于2015 年开始对全国提供眼科服务的三级医疗机构通过网上填报的方式进行普查，采用描述性统计方法和χ2检验，对我国三级医疗机构低视力服务专业人员配置和服务提供情况进行系统整理和统计分析。结果：本次调查覆盖全国1 508 家三级医疗机构，其中提供低视力诊疗康复服务的有559 家（37.07%），未提供服务的有949 家（62.93%），各级医疗机构在是否开展低视力康复服务方面差异有统计学意义（χ2=61.94，P<0.001）。在提供服务的机构中，已设立低视力专业门诊的有338家（60.47%），低视力年平均门诊量为964例。从事低视力医疗康复服务专业人员2 993 人，平均每家三级医疗机构有低视力专业医师1.98 人、护士0.46 人、技师0.41 人、辅助人员0.22 人。三级医疗机构以儿童功能性视力康复训练、低视力社区教育宣传和助视器验配为主要低视力服务类型。结论：我国三级医疗机构低视力学科建设亟待加强，专业人员总量偏低、人才梯队建设不完善，服务质量低、服务类型单一，无法满足我国低视力患者全方位的服务需求。     

Barriers to accessing low vision services

AIM: To investigate barriers to accessing low vision services in Australia. METHODS: Adults with a vision impairment (<6/12 in the better eye and/or significant visual field defect), who were current patients at the Royal Victorian Eye and Ear Hospital (RVEEH), were interviewed. The questions investigated self-perceived vision difficulties, duration of vision loss and satisfaction with vision and also examined issues of awareness of low vision services and referral to services. Focus groups were also conducted with vision impaired (<6/12 in the better eye) patients from the RVEEH, listeners of the Radio for the Print Handicapped and peer workers at Vision Australia Foundation. The discussions were recorded and transcribed. RESULTS: The questionnaire revealed that referral to low vision services was associated with a greater degree of vision loss (p = 0.002) and a greater self-perception of low vision (p = 0.005) but that referral was not associated with satisfaction (p = 0.144) or difficulties related to vision (p = 0.169). Participants with mild and moderate vision impairment each reported similar levels of difficulties with daily activities and satisfaction with their vision (p > 0.05). However, there was a significant difference in the level of difficulties experienced with daily activities between those with mild-moderate and severe vision impairment (p < 0.05). The participants of the focus groups identified barriers to accessing low vision services related to awareness of services among the general public and eye care professionals, understanding of low vision and the services available, acceptance of low vision, the referral process, and transport. CONCLUSION: In addition to the expected difficulties with lack of awareness of services by people with low vision, many people do not understand what the services provide and do not identify themselves as having low vision. Knowledge of these barriers, from the perspective of people with low vision, can now be used to guide the development and content of future health-promotion campaigns.     

Developing an integrated paediatric low vision service.

A survey of usage of low vision aids (LVAs) by 56 children with visual impairment, who were attending mainstream schools in Wirral, was undertaken. A total of 25% of children owned an LVA and 5% were using these on a regular basis. These low levels of ownership and usage led to the development of a low vision service involving the collaboration of education and health care. This paper describes the development of that service, its elements and implementation. The results from the new service show that of the 29 children issued with an LVA, 82.7% are using them on a regular basis. Having an integrated service is shown to significantly improve LVA usage in the group of children seen so far. The service results are discussed with suggestions for future service development.     

The Developmental History and an Evaluation of the Queensland Low Vision Care Centre

ABSTRACT: The decisive shift in attitute from partial blindness and conservation of residual vision towards partial sightedness and maximal use of residual vision in the last fifteen years has resulted in low vision care being a relatively new field of particular concern to health care professionals. In Australia, the first multi-disciplinary clinic providing a comprehensive low vision service was established at the Association for the Blind, Kooyong, Victoria in 1972. Since then, a number of low vision clinics in a variety of locations have developed throughout Australia, with the establishment of the Low Vision Care Centre in Brisbane, Queensland occurring in 1979. This paper describes the developmental history of this service and evaluates the comprehensive low vision care which this clinic provides to the Queensland population. The effectiveness and future considerations of this service are also discussed.     

Low vision device requirements among children from two schools for the blind in Tamil Nadu

Purpose:To identify children with low vision from two local schools for the blind, to provide low vision devices (LVD) to those who may benefit from it, and to encourage them to learn print.Methods:A prospective study was conducted among children from two local schools for the blind. Best-corrected visual acuity (BCVA) was done using the Snellen chart. Children with BCVA of counting finger (CF) 1/2 meter or more in the better eye underwent low vision assessment. Distant vision was assessed using the Feinbloom chart and near vision was assessed using the Lea symbol chart. Low vision devices (LVD) were prescribed as required.Results:Among 185 children enrolled, 31 children had BCVA of >CF ½ meter. Using a telescope, distant vision was better than 3/36 in 48.4%, 3/36–3/12 in 16.2%, and 3/9.5 to 3/3 in 35.4%. Among 23 children who read 1M at <10 cm, 22.6% could read 0.6–0.8M, and 25.8% could read 1M using LVD.Conclusion:Regular screening of children in schools for the blind could identify children who might benefit from LVD. A review of protocols for the entry of children in schools for the blind by screening these children by a specialist team prior to admission should be made mandatory.     

视力低常的学龄前儿童屈光不正的分布规律研究

目的:观察与研究锦州市1 170例学龄前儿童视力低常的儿童屈光不正的分布规律.方法:抽取锦州市城区10所幼儿园,对3～6岁学龄前儿童进行视觉状况调查,分别进行视力检查、眼位检查、屈光状态检查、眼科常规检查以及立体视检查等.对于视力低于0.8的儿童进行散瞳验光.结果:(1)视力低常率:3岁为6.37％,4岁为7.79％,5岁为15.24％,6岁为8.93％,5岁儿童低常率明显高于其他年龄组,差异有显著性(P＜0.05);(2)视力低常眼病分布:视力低常患者中,屈光不正占95.61％.屈光不正分布:远视71.67％,其中3岁为75.00％,4岁为78.26％,5岁为75.44％,6岁为54.17％;近视17.50％,其中3岁为6.25％,4岁为13.04％,5岁为17.54％,6岁为29.17％;混合散光10.83％,其中3岁为18.75％,4岁为8.70％,5岁为7.02％,6岁为16.67％;(3)弱视情况:弱视患病率4.27％.对弱视相关因素调查显示,屈光参差性占36.00％,轻度66.67％,中度27.78％,重度5.56％;斜视性占16.00％,轻度25.00％,中度62.50％,重度12.50％;形觉剥夺性占2.00％,轻度0％,中度0％,重度100.00％.结论:学龄前儿童年龄较大者比年龄较小者视力较好,说明年龄的增长儿童视功能发育逐渐成熟.屈光不正中各组比例提示,远视是3～6岁学龄前儿童视力低下的主要原因.近视、斜视、弱视等因素所占比例提示普查手段十分重要,应早发现早治疗.     

盲及低视力的先天性白内障患儿术后的视觉康复

目的 :探讨远用和近用助视器在先天性白内障术后视残儿童中的应用效果。方法 :对 31例 (5 4只眼 )患儿分别配戴了单筒或双筒远用望远镜助视器和近用眼镜助视器。结果 :配戴远用助视器后 ,9只盲眼中有 8只眼远视力≥ 0 0 5 ,脱盲率为 88 9%。原 4 5只眼低视力中有 36只眼远视力提高到≥ 0 3,其中 17只眼可达 0 5或以上 ,脱残率为 80 0 %。 2 4例 (45只眼 )选用了近用眼镜助视器 ,15例近视力提高后达≥ 0 5。结论 :助视器在低视力门诊是必备的且有效的 ,可提高患儿视力 ,提高学习生活能力。积极推进视残儿童视觉康复工作是眼科工作者义不容辞的责任。     

三亚市郊≥50岁人群低视力及盲流行病学调查

目的:调查海南省三亚市郊≥50岁人群中低视力及盲的发病率并分析其原因。方法:随机抽取28个抽样单位的≥50岁人群共2569例进行调查。对调查人员进行矫正视力、外眼、前房、晶状体、玻璃体及眼底检查。观察其低视力及盲的患病率,分析致盲的重要原因。结果:2569例中受检2206例,受检率85.87%,低视力和盲的患病率分别为3.85%和1.90%。致盲主要眼病依次为白内障、青光眼、角膜病、眼睑疾病及翼状胬肉。结论:白内障依然是低视力和盲的首要病因,但眼睑疾病及翼状胬肉致盲也不容忽视。