Clinical performance of electronic, head-mounted, low-vision devices

This study compared four electronic head-mounted devices (HMDs) (Jordy, Flipperport, Maxport and NuVision) with conventional optical low-vision aids (LVAs). The aim was to determine any performance differences for laboratory-based clinical measurements and practical visual tasks for patients with macular disease. Possible factors influencing success were explored. Ten patients with early onset macular disease (EOMD) and 10 with age-related macular disease (AMD) used the four HMDs, habitual spectacles and previously prescribed optical LVAs to complete a range of clinical measurements and everyday visual tasks. The clinical measurements were distance, intermediate and near acuities, and contrast sensitivity. The visual tasks were to read text of three sizes, to write a cheque and to identify grocery items on a shelf. Following the initial evaluation, each subject took home two randomly selected HMD devices for 2 weeks, after which performance measures were repeated. No single HMD stood out as being superior overall. Flipperport and Jordy provided significantly better distance and intermediate acuity than the previously prescribed optical LVAs but near acuity and contrast sensitivity were not consistently better with any of the HMDs. Practice at home provided some improvement in performance with HMDs, nevertheless, optical aids remained the best devices for optimum functioning for the majority of tasks. Younger patients and those with better distance acuity were more likely to benefit from HMDs, particularly when reading small print. In low vision clinics, practitioners should continue to show patients conventional optical aids and demonstrate these electronic HMDs only when appropriate for the individual patient.     

Difficulty in performing everyday activities in patients with juvenile macular dystrophies: comparison with patients with retinitis pigmentosa

AIMS—To ascertain the level of perceived difficulty experienced by patients with central vision loss due to juvenile macular dystrophies in the performance of everyday activities. A second objective was to compare their perceived difficulty with that of patients with retinitis pigmentosa (RP) with primarily peripheral vision loss.
METHODS—72 patients with Stargardt disease, cone dystrophy, or cone-rod dystrophy who had visual acuities worse than 20/40 and normal peripheral visual fields rated themselves on their difficulty in the performance of 33 activities encompassing a wide variety of everyday tasks. These findings were compared with the responses of 120 patients with typical RP or Usher syndrome type 2 who had visual acuities of 20/40 or better and peripheral visual field loss.
RESULTS—The juvenile macular dystrophy group reported the greatest level of overall self perceived difficulty with activities involving central vision, and lesser and variable degrees of difficulty with items within the mobility, negotiating steps, driving, and miscellaneous categories. Consistent with these findings, there were highly significant correlations between subjects' rated performances of activities involving central vision and the clinical measures of vision, including visual acuity and size of central scotoma. There were fewer significant correlations between perceived performance of activities in the other categories and the clinical measures. In general, those activities that showed significant correlations with the clinical measures of vision for the patients with juvenile macular dystrophies also showed significant differences in the patterns of responses between the juvenile macular dystrophy group and the RP group. Those items which were not correlated with the clinical measures in the juvenile macular dystrophy group tended not to show significant differences in the response patterns between the two groups.
CONCLUSION—These results provide insight into the types of perceived difficulties in performing tasks of everyday life in patients with these disorders which affect counselling of these patients.

Keywords: vision; impairment; everyday activities; juvenile macular dystrophy     

Monitoring for neovascular age-related macular degeneration (AMD) reactivation at home: the MONARCH study

AimsThis study aims to quantify the diagnostic test-accuracy of three visual function self-monitoring tests for detection of active disease in patients with neovascular age-related macular degeneration (nAMD) when compared with usual care. An integrated qualitative study will investigate the acceptability of these home-based testing strategies.MethodsAll consenting participants are provided with an equipment pack containing an iPod touch with two vision test applications installed and a paper journal of reading tests. Participants self-monitor their vision at home each week with all three tests for 12–18 months. Usual care continues over this period. Key eligibility criteria are: age ≥50 years; at least one eye with AMD with ≥6–≤42 months since first AMD treatment; and vision not worse than Snellen 6/60, LogMAR 1.04 or 33 letters. The primary outcome, and reference standard, is diagnosis of active disease during usual care monitoring in the Hospital Eye Service. Secondary outcomes include duration of study participation, ability of participants to do the tests, adherence to weekly testing and acceptability of the tests to participants.ConclusionsRecruitment is in progress at five NHS centres. Challenges in procuring equipment, setting up the devices and transporting devices containing lithium batteries to participating sites delayed the start of recruitment. The study will describe the performance of the tests self-administered at home in detecting active disease compared to usual care monitoring. It will also describe the feasibility of the NHS implementing patient-administered electronic tests or similar applications at home for monitoring health.Subject terms: Macular degeneration, Outcomes research, Eye manifestations     

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.     

不同程度视力残疾儿童应用助视器康复的研究

目的对有残余视力的视力残疾儿童在给予光学和电子助视器康复后进行远、近视力的分析和效果评估,探讨不同程度视力残疾患儿有效的康复手段及其对低视力康复对象范围界定的影响。方法对盲校及低视力门诊共206名4～14周岁（含14岁）视力残疾儿童按视力残疾的程度进行分组,比较应用国产4倍、6倍望远镜前后远视力和应用国产眼镜式助视器、国产简易电子助视器后两种助视器间阅读成功率的差异。远视力康复结果采用秩和检验,近视力康复结果采用卡方检验进行统计学分析。结果视力0．05以下至眼前指数的盲童组和0．3以下至0．05的低视力组应用远用助视器前后远视力差异均有统计学意义（P〈0．05）;视力0．05以下至光感的肓童和低视力儿童分别使用眼镜式近用助视器与简易电子助视器后,两种助视器间阅读成功率的差异均有统计学意义,使用简易电子助视器的阅读成功率均明显高于使用眼镜式近用助视器。结论助视器康复的对象可以从低视力范围扩展到0．01甚至以下的盲童。低视力助视器是视力残疾儿童视觉康复有效和必要的手段,早期视觉康复特别是使用简易电子助视器进行近视力阅读的康复,对视力残疾儿童提高学习认知能力、促进身心健康成长和回归社会具有重要意义。     

Age-related macular degeneration and low-vision rehabilitation: a systematic review

BACKGROUND: Because of the prevalence and devastating consequences of age-related macular degeneration (AMD), a systematic review devoted to low-vision rehabilitation and AMD seems timely and appropriate. METHODS: Several electronic databases were searched for studies from 1980 to 2006 involving individuals with low vision or visual impairment and rehabilitation interventions. Studies were assessed for quality and level of evidence. RESULTS: The findings indicate that standard low-vision rehabilitation programs, conventional in-clinic assessments, and optical devices are effective ways of managing and living with vision loss. Areas of unmet need include determining which types of orientation and mobility programs and devices are most effective and developing methods of matching assistive technologies with the individual's visual and environmental requirements. INTERPRETATION: Additional randomized controlled trials with similar intervention comparisons and outcome measures are needed to form stronger conclusions for the most effective low-vision rehabilitation interventions for individuals with AMD.     

不同程度视力残疾患者应用助视器的康复效果

目的探讨不同程度视力残疾患者在应用光学和电子助视器后远、近视力的康复效果。方法对天津医科大学眼科中心低视力康复中心283例(9～79岁)视力残疾患者按视力残疾程度分为盲(110例)和低视力(173例)两组。分别比较两组应用Keplerian及Galilean望远镜前后远视力及脱残率的差异,以及应用带光源手持放大镜、近用眼镜式助视器及电子助视器后阅读成功率的差异。应用助视器前后的远视力差异采用配对t检验,脱残率及阅读成功率的差异采用χ2检验。结果两组应用两种远用助视器后远视力均有所提高,差异均有统计学意义(均为P<0.01);盲目组应用Keplerian及Galilean望远镜后脱残率分别为10.9%和9.1%,低视力组分别为76.3%和77.5%,差异均无统计学意义(P=0.823、P=0.899)。两组应用电子助视器阅读成功率(26.4%、86.1%)均高于带光源手持放大镜(13.6%、71.1%)及近用眼镜式助视器(15.5%、68.2%),差异均有统计学意义(P=0.031、P<0.01)。结论助视器能帮助视力残疾患者有效利用其残余视力,改善视功能及提高生活质量,是视力残疾患者康复的有效手段,应加强宣传及推广普及。     

Electronic restoration of vision in those with photoreceptor degenerations

Complete loss of vision is one of the most feared sequelae of retinal disease. Currently, there are few if any treatment options available to patients that may slow or prevent blindness in diseases caused by photoreceptor loss, such as retinitis pigmentosa and age‐related macular degeneration. Electronic restoration of vision has emerged over recent years as a safe and viable option for those who have lost substantial numbers of photoreceptors and who are severely vision impaired. Indeed, there has been a dramatic increase in our understanding of what is required to restore vision using an electronic retinal prosthesis. Recent reports show that for some patients, restoration of vision to the point of reading large letters is possible. In this review, we examine the types of implants currently under investigation and the results these devices have achieved clinically. We then consider a range of engineering and biological factors that may need to be considered to improve the visual performance of newer‐generation devices. With added research, it is hoped that the level of vision achieved with newer generation devices will steadily improve, resulting in enhanced quality of life for those with severe vision impairment.     

Simulating prosthetic vision: II. Measuring functional capacity

Investigators of microelectronic visual prosthesis devices have found that some aspects of vision can be restored in the form of spots of light in the visual field, so-called “phosphenes”, from which more rich and complex scenes may be composed. However, questions still surround the capabilities of how such a form of vision can allow its recipients to “see” and to carry out everyday activities. Through simulations of prosthetic vision, researchers can experience first-hand many performance and behavioral aspects of prosthetic vision, and studies conducted on a larger population can inform the performance and behavioral preferences in general and in individual cases. This review examines the findings from the various investigations of the functional capacity of prosthetic vision conducted through simulations, especially on the topics of letter acuity, reading, navigation, learning and visual scanning adaptation. Central to the review, letter acuity is posited as a reference measurement so that results and performance trends across the various simulation models and functional assessment tasks can be more readily compared and generalized. Future directions for simulation based research are discussed with respect to designing a functional visual prosthesis, improving functional vision in near-term low-phosphene-count devices, and pursuing image processing strategies to impart the most comprehensible prosthetic vision.     

白内障术后低视力的相关因素分析

目的：对白内障超声乳化联合人工晶状体植入术后低视力的相关因素进行分析,用于术前评估预后。
　　方法：对白内障超声乳化联合人工晶状体植入术341例418眼行术前术后相关检查,术后采用国际标准视力表行最佳矫正视力检查,进行术后低视力的相关因素分析。
　　结果：术后1 mo低视力发生率为10.3%,发生低视力的危险因素包括合并原发病及晶状体核硬度,合并原发病主要有年龄相关性黄斑变性(48.8%)、糖尿病性视网膜病变(39.0%)、青光眼性视神经病变(7.3%)、病理性近视眼底改变(2.4%)、视网膜分支静脉阻塞合并黄斑水肿(2.4%)。
　　结论：影响白内障超声乳化联合人工晶状体植入术后低视力的相关因素包括合并原发病及晶状体核硬度。提示我们临床工作中重视术前检查,术中谨慎操作保护视功能。     

Reading speed test for potential central vision measurement

This study examines the validity and reliability of a reading speed test as a measure of potential central vision. Reading speed was calculated in words per minute (wpm) from the time taken to read 30 words of 1.20 logMAR size text. Scores were obtained from subjects with cataract (n = 48), macular disease(n = 35), peripheral vision loss(n = 14) and normal eyes (n = 10). Subjects with macular disease (27.0 +/- 13.2 wpm) read much slower than subjects with cataract (91.9 +/- 13.6 wpm). Little difference was found between subjects with cataract, peripheral vision loss (91.5 +/- 14.7 wpm)and normal eyes (103.8 +/- 15.5 wpm). Repeat testing gave values within +/- 16% of reading speed. These results suggest that a reading speed test using large text could be useful as a potential central vision test in cataract patients.     

影响孔源性视网膜脱离术后视力的因素分析

目的:探讨孔源性视网膜脱离(rhegmatogenous retinalde-tachment,RRD)术后视力的恢复情况及其影响因素。方法:回顾性分析我院眼科2002-01/2007-10期间,以孔源性视网膜脱离为第一诊断并经手术治疗视网膜复位成功的病历资料,共99例102眼。其中采用巩膜外路手术81眼、玻璃体联合视网膜手术21眼。观察RRD患者的发病年龄、视网膜脱离范围、视网膜脱离时间、增生性玻璃体视网膜病变(proliferative vitreoretinopathy,PVR)程度、黄斑状态、屈光状态、裂孔位置、手术前后视力、术后裂孔封闭及视网膜复位情况,用卡方检验对不同年龄、视网膜脱离范围、视网膜脱离时间、PVR分级、黄斑状态及屈光状态的患者术后视力变化情况进行分析,根据结果选择差异有统计学意义的因素进行Spearman等级相关检验。结果:视网膜复位术后视力提高53眼(52.0%),视力不变33眼(32.3%),视力下降16眼(15.7%)。不同PVR分级、黄斑状态、视网膜脱离范围、视网膜脱离时间及年龄的术后视力恢复情况有显著差别(P<0.05),不同屈光状态的术后视力恢复情况无明显差别。对上述因素进行Spearman等级相关检验,发现上述术前因素与术后视力关联程度从大到小为:PVR分级(rs=-0.521,P=0.000)、黄斑是否脱离(rs=-0.446,P=0.000)、视网膜脱离时间(rs=-0.423,P=0.000)、视网膜脱离范围(rs=-0.411,P=0.000)、患者年龄(rs=-0.267,P=0.007)。结论:RRD患者的术后视力恢复与术前PVR分级、黄斑状态、视网膜脱离时间、视网膜脱离范围、年龄有关,其中术前PVR分级、黄斑状态、视网膜脱离时间对术后视力的恢复影响最为显著。     

Visual function and biofeedback training of patients with central vision loss: a review

Older individuals with macular diseases, such as age-related macular degeneration, experience central vision loss (CVL) due to degeneration of their photoreceptors and retinal cells. Patients with CVL may experience various vision impairments, including of visual acuity, fixation stability, contrast sensitivity, and stereoacuity. After CVL, most patients develop a preferred retinal locus outside the affected macular region, which serves as a new visual reference. In this review, we provide an overview of the visual function and impairment in individuals with CVL. In addition, the important role of biofeedback training on the visual function and activity of individuals with CVL is also reviewed. Accordingly, the location and development of the preferred retinal loci are discussed. Finally, this review discusses how to conduct biofeedback training to treat individuals with CVL.     

光学相干断层扫描在白内障术后低视力原因分析中的应用

目的 :探讨光学相干断层扫描图像在分析白内障术后低视力中的应用。方法 :对术后矫正视力低于 0 5的 48例 (4 8眼 )病人行OCT检查 ,分析其结果。结果 :48眼中黄斑水肿 2 1眼 ,老年性黄斑变性 8眼 ,糖尿病眼底病变 5眼 ,视网膜中央静脉栓塞 2眼 ,视神经萎缩 2眼 ,视网膜脱离 1眼 ,黄斑板层裂孔 2眼 ,7眼未发现异常。结论 :OCT是一种新的、非接触的诊断技术 ,在白内障术后低视力原因分中 ,它能快速准确地检查出低视力的原因 ,并能客观的检测临床治疗效果。     

Parental Home Vision Testing of Children During Covid-19 Pandemic

Background:The Covid-19 pandemic necessitated social distancing restrictions, which placed limitations on access to ophthalmic care to only those who had an imminent risk of sight loss. All other face-to-face consultations were converted to telephone consultations or were postponed. We investigated whether parents were able to test their child’s vision using available home vision testing applications, with an aim to aid decision making during a telephone consultation.Methods:Families with follow-up consultations at Birmingham Children’s Hospital were asked to test their child’s vision at home. Instructions for the use of Peek acuity, or iSight Pro, were emailed to a parent. Parents chose to use a particular app based on available devices at home. Parents were asked to test uniocular visual acuity twice. Home versus hospital acuity was correlated. Home acuity test-retest reliability was acquired. Parental feedback was obtained through questionnaires.Results:One hundred and three families were contacted, 15 families completed home vision testing. Ten families used Peek acuity, five families used iSight Pro. Uniocular visual acuity test-retest reliability was 0.03 LogMAR. Home-hospital acuity testing had a bias of 0.14 LogMAR, hospital acuity yielding a lower LogMAR score. Most families who completed testing found it easy to do; however, some struggled, and 81 families did not undertake home vision testing.Conclusions:Uptake of home vision testing was limited by parental engagement, most likely influenced by the current pandemic. Most families who undertook home vision testing were able to generate results that could be used for clinical decision making. Extending the impact of parental vision testing will require education by clinicians and further study to increase sample sizes and to improve confidence.     

A Randomized Controlled Trial Assessing the Effectiveness of Strategies Delivering Low Vision Rehabilitation: Design and Baseline Characteristics of Study Participants

Purpose: To design a randomized controlled trial (RCT) to compare the effectiveness of four different strategies to deliver low vision rehabilitation services.

Methods: The four arms of the RCT comprised—center based rehabilitation, home based rehabilitation, a mix of center based and home based rehabilitation, and center based rehabilitation with home based non interventional supplementary visits by rehabilitation workers. Outcomes were assessed 9 months after baseline and included measuring changes in adaptation to age-related vision loss, quality of life, impact of vision impairment and effectiveness of low vision rehabilitation training. The socio-demographic and vision characteristics of the sample in each of the 4 arms were compared to ensure that outcomes are not associated with differences between the groups.

Results: Four hundred and thirty six individuals were enrolled in the study; 393 individuals completed the study. One-fifth of participants were children aged 8 to 16 years. At baseline, socio-demographic and clinical characteristics were similar between individuals in the four arms of the trial. Socio-demographic and clinical characteristics did not differ significantly, except for age, between the 393 individuals who completed the trial and the 43 individuals who dropped out of the study. Twenty six (60.46%) of the forty three drop outs were from the center based arm of the trial.

Conclusions: Information from this trial has the potential to shape policy and practice pertaining to low vision rehabilitation services.     

白内障超声乳化摘除联合人工晶状体植入术后低视力原因分析

目的:探讨白内障超声乳化摘除联合人工晶状体植入术后低视力的原因及可能的预防和术后处理。方法:收集我院2008/2010年资料完整的成人白内障超声乳化手术患者998例,回顾分析术后随访3mo后视力<0.3的原因。结果:术后3mo随访视力<0.3的患者有130眼,发生率为13.0%。结论:成人白内障超声乳化摘除联合人工晶状体植入术治疗白内障,术后出现低视力的主要原因是眼部原有的疾病,常见是老年性黄斑变性、糖尿病视网膜病变和青光眼所致的视神经损伤。     

OCT对糖尿病患者白内障超声乳化术后低视力原因的分析

目的:应用OCT对糖尿病患者白内障超声乳化吸除术后低视力的原因进行分析。 方法:对术后3d矫正视力低于0.5的50例50眼糖尿病患者行OCT检查,分析其结果。 结果:患者50眼中,黄斑水肿23眼,糖尿病眼底病变15眼,年龄相关性黄斑变性8眼, 黄斑板层裂孔2眼,2眼未发现异常。 结论:OCT作为一种新型的高分辨率的视网膜断层成像技术,对于糖尿病患者白内障术后造成低视力的原因的诊断具有指导作用,糖尿病白内障患者超声乳化吸除术后的黄斑水肿是影响术后低视力的主要原因之一。     

助视器对年龄相关性黄斑变性患者视功能恢复和阅读速度的影响

目的:评估助视器对年龄相关性黄斑变性(AMD)患者视功能恢复和阅读速度的影响。方法:对低视力门诊44名AMD患者进行评估。收集并分析使用助视器前和使用助视器时裸眼视力、最佳矫正视力、屈光状态、助视器类型(LVAs)以及阅读速度的相关数据。结果:共44例AMD患者,平均年龄为73±10.8岁,男性36例(82%)。其中,29例(67%)受试者视力较好的眼远视力(DVA)为1.0~1.6 LogMAR,而36例(82%)受试者近视力(NVA)小于3.2 m。使用助视器时平均DVA提高0.67±0.27 LogMAR(P=0.000)。使用LVAs时,42例患者NVA达到1 m甚至更佳,仅有2例(4.5%)没有使用LVAs的患者NVA为1 m。在使用一定时间的助视器后,有阅读能力的患者平均阅读速度从每分钟2.9±4.78字提高到每分钟71.31±29.96字(P<0.001)。15名受试者远距离视觉使用单目望远镜,而戴高倍单目镜片眼镜作为最常用的阅读辅助工具。结论:LVAs对AMD患者的视功能恢复和阅读能力的提高有一定的作用。对于AMD患者而言,接受低视力护理服务是有必要的。     

葡萄膜炎性黄斑水肿对视功能的影响

目的:探讨葡萄膜炎性黄斑水肿对视力、视野损害的相关性.方法:此研究为单中心、回顾性的、对临床中发现的中间、后部或全葡萄膜炎治疗的特征性对照研究.葡萄膜炎性黄斑水肿患者132例248眼,接受视力、频域光学相干断层扫描、微视野检测.结果:葡萄膜炎性黄斑水肿与视力、视野的损害具有明显的相关性(P＜0.05).不同类型的黄斑水肿对应不同的视力损害:不伴有黄斑中心凹厚度增加的囊腔型可产生中等程度的视力损害,平均10个字母;不伴有囊腔而仅有黄斑中心凹厚度增加型可产生更大程度的视力损害,平均19个字母;而同时伴有囊腔、黄斑中心凹厚度增加的黄斑囊样水肿型可产生最大程度的视力损害,平均26个字母.入选的所有黄斑水肿都产生了不同程度的视野损害:与黄斑中心凹的的厚度密切相关,即厚度越大,视野损害的范围越广,差异具有统计学意义(P＜0.05),而与是否具有囊腔关系不大.结论:黄斑水肿对应的视功能损害提示我们在以后的葡萄膜炎治疗过程中,对黄斑水肿的治疗也应作为一个重要方面去关注;对葡萄膜炎性黄斑水肿的视功能损害评估,应该从视力和微视野两方面关注.