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。     

Improvement of reading speed after providing of low vision aids in patients with age‐related macular degeneration

Purpose: Age‐related macular degeneration (AMD) is the most common cause of severe visual impairment, including loss of reading ability, among elderly persons in developed countries. The aim of the present study was to evaluate reading ability before and after providing of appropriate low vision aids. Methods: Five hundred and thirty patients with different stages of AMD (age 82 ± 8 years) were included in this retrospective study. All patients underwent a standardized ophthalmological examination including evaluation of magnification requirement and careful providing of low vision aids. Before and after the provision of low vision aids, reading speed [words per minute (wpm)] was evaluated using standardized reading texts. Results: For the whole group, the average best‐corrected distance visual acuity of the better eye was 0.18 ± 0.15, with 69% of patients having visual acuity of 0.1 (20/200) or better. The mean magnification requirement was 7.4 ± 6.3‐fold (range 2–25). Visual rehabilitation was achieved with optical visual aids in 58% of patients, whereas 42% of patients needed electronically closed‐circuit TV systems. Mean reading speed was 20 ± 33 wpm before and increased significantly to 72 ± 35 (p < 0.0001) after the provision of low vision aids for the whole group. Between patients with visual acuity < 0.1 and patients with visual acuity of 0.1 or better, there are highly significant differences in reading speed before (0.4 ± 3.8 versus 20 ± 28 wpm, p ≤ 0.0001) and after providing of visual aids (40 ± 13 versus 84 ± 30 wpm, p ≤ 0.0001). Patients with severe visual impairment (visual acuity ≤ 0.1) showed significantly lower improvement of reading speed compared to patients with visual acuity of 0.1 or better following rehabilitation (p ≤ 0.0001). Before providing of low vision aids, only 16% of patients were able to read; in contrast, reading ability was achieved in 94% of patients after the provision of low vision aids for the whole group. Conclusion: Our results indicate the great value of low vision rehabilitation through adequate providing of vision aids for the improvement of reading ability, with a highly significant increase of reading speed without training of eccentric viewing in patients with retained central fixation. The prompt implementation of low vision aids in patients with macular degeneration will help them to maintain and regain their reading ability, which can lead to an increase in independence, communication, mental agility and quality of life.     

Prescribing near magnification for low vision patients

Most patients with low vision request help with reading. Despite improvements in the assessment of visual functions, determining the appropriate magnification for reading still often involves a trial and error approach. Recent research has shown that with accurate and systematic assessments of vision, the required magnification can be predicted but this magnification needs to be much higher than has been previously recommended. This paper presents a systematic approach to enable practitioners to determine the power of a near addition or simple magnifier needed to assist patients with mild or moderate low vision who may present seeking help for reading. Guidelines for appropriate referral to low vision services are also provided.     

Training to improve temporal processing of letters benefits reading speed for people with central vision loss

Reading is slow and difficult for many people with central vision loss. A previous study showed that the temporal threshold for letter recognition is a major factor limiting reading speed for people with central vision loss. Here, we asked whether the temporal threshold for letter recognition for people with central vision loss could be improved through training and, if so, whether that would benefit reading. Training consisted of six sessions (3000 trials) of recognizing letter trigrams presented at fixation. Trigrams were initially presented at a baseline temporal threshold that was decreased by 0.1 log step when observers’ letter recognition accuracies reached 80% or higher for four consecutive blocks. Before and after training, we measured observers’ visual acuity, preferred retinal locus for fixation, fixation stability, reading speeds using the rapid serial visual presentation (RSVP) paradigm, the MNREAD Acuity Chart and 100-word passages, the baseline temporal threshold for letter recognition at 80% accuracy, and a visual-span profile. After training, the temporal threshold was decreased by 68%. This improvement was accompanied by a higher RSVP maximum reading speed (but no change in MNREAD and passage reading speeds) and a larger visual span. A mediation analysis showed that the relationship between the temporal threshold and RSVP maximum reading speed was mainly mediated by the information transfer rate (size of visual span/temporal duration). Our results showed that the temporal threshold for letter recognition is amenable to training and can improve RSVP reading speeds, offering a practical means to improve reading speed for people with central vision loss.     

Reading with low vision: the impact of research on clinical management*

The past 40 years has seen a great expansion in low‐vision research, which has changed low‐vision teaching and our clinical management of people with low vision. Australian optometrists have contributed significantly to this research and the development of multidisciplinary low‐vision services. This paper reviews the research that has shaped our clinical assessment and patient management for reading by adults with low vision. The major improvements in clinical assessment of low vision for reading were brought about by the improvements in distance and near visual acuity measurements during the 1970s and research during the 1980s and 1990s showing the factors affecting the reading rate. These changes, together with a different method for representing the magnification provided by optical and electronic systems, allows a scientific, logical and practical method for prescribing magnification. An illustration of the step‐by‐step approach for prescribing magnification for low‐vision reading that is easy to apply in any clinical practice is included.     

Using the real-life vision test to assess the functional vision of age-related cataract patients

Purpose

(1) To describe and validate a newly developed, timed performance-based measures of functional vision—the real-life vision test (RLVT). (2) To determine how RLVT relates to clinical measures and self-report assessment of visual function and the complex interactions among visual impairment, psychosocial status, and demographic factors.

Methods

A total of 64 patients with age-related cataract and 45 age-matched controls were evaluated by four types of measurements: (1) demographic, medical, cognitive, and depressive evaluation and the reaction time (RT) testing; (2) clinical measures (visual acuity, contrast sensitivity, stereopsis, and the color perception); (3) the 25-item National Eye Institute''s Visual Functioning Questionnaire; and (4) the RLVT. Spearman''s coefficients, partial correlation, and multiple regression analysis were conducted to determine the relationship among RLVT, clinical measures, and self-report assessment of visual function while controlling for confounders.

Results

Control subjects performed RLVT significantly better than the cataract patients. RLVT correlated well with both clinical and self-report assessments of visual function. All subscales of RLVT remained highly associated with most of the clinical measures, even after adjusting for age, years of education, depression, cognitive status, and the RT. Distance, intermediate and near visual acuity, and binocular contrast sensitivity were significant predictors of the RLVT performances.

Conclusions

Given the strong relationship among RLVT, clinical measures, and the self-report assessments, our results highlight the potential usefulness of RLVT for assessing the functional vision of cataract patients. RLVT may provide information not obtainable from clinical measures or surveys and therefore it is essential to be incorporated into future ophthalmological practice.     

白内障手术能加快老年性黄斑变性进展吗？

老年人往往同时罹患老年性白内障和老年性黄斑变性两种眼病,长期以来对于白内障手术是否影响老年性黄斑变性的病情一直存在争议。先前的报道多认为白内障手术加快了老年性黄斑变性的进展,而近年的报道多认为白内障手术并未加快老年性黄斑变性的进展,反而更多地改善了患者的视觉功能,这与白内障手术的进步和超声乳化技术的运用是分不开的。（跟科,2010,19：73－75）     

萎缩型年龄相关性黄斑变性形态学及功能学检查技术进展

年龄相关性黄斑变性(age-related macular degeneration,AMD)是50岁以上人群主要的致盲性眼病,其中萎缩型占AMD患病总数的85％ ～ 90％.随着光谱成像、眼底自发荧光、光学相干断层扫描、微视野、多焦视网膜电流图及其他新方法在眼科临床的应用,人们对萎缩型AMD病变的形态及功能改变有了更深入和全面的认识,本文就近年来的相关进展予以综述.     

抗氧化剂治疗年龄相关性黄斑变性的研究

年龄相关性黄斑变性（AMD）是西方55岁以上老年人低视力和盲的首要原因,发病机制尚不明确,缺乏可靠的预防和治疗方法。近年来国内外很多学者就AMD早期药物防治进行了广泛的实验与临床研究,重点是抗氧化剂的作用。就锌制剂,维生素A、C、E,多聚不饱和脂肪酸,类胡萝卜素（主要是叶黄素和玉米黄质）等的研究现状进行综述。     

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。     

Provision and utilization of low-vision rehabilitation services in Toronto

BACKGROUND: Demographic changes expected to occur in the near future and the need for planning to address them are behind the urgent drive to assess present day provision and utilization of low-vision rehabilitation (LVR) services in the community. Current data available in Canada in this regard are mostly from Canadian National Institute for the Blind (CNIB) sources from clients accessing services, and are therefore incomplete. The purpose of this study, therefore, was to survey the provision and utilization of LVR services as reported by patients identified with low vision (LV) outside the CNIB system, specifically among those attending hospital-based ophthalmology clinics. METHODS: The study design was a prospective, nonrandomized, observational case series based on interviews with LV patients. Cases with LV identified according to preset criteria were interviewed and tested for best-corrected visual acuity. The interview format included questions on multiple outcome measures of LVR, which provided answers addressing the theme of this study. A separate questionnaire was used to assess quality-of-life measures. RESULTS: Thirty-four subjects were recruited for the study, 21 females and 13 males, with a mean age of 74 (SD 16) years. LV had been present for a mean of 8.26 (SD 12.2) years, mostly caused by age-related macular degeneration (44%) and other maculopathies (38%). Patients classified as having LV were referred to LVR services only in 50% of cases and mostly to CNIB offices (47%). The majority of cases (59%) used magnifiers as the most common remedy for LVR. A majority of cases (59%) felt that current rehabilitation services are insufficient and that more LVR interventions were warranted in their case. INTERPRETATION: Many cases with LV are not referred to LVR services. Those referred are directed mainly to the CNIB, bypassing other advanced and comprehensive suppliers of LVR services. The majority of cases express dissatisfaction with the current LVR services provided. There is a clear and urgent need to expand and reform the delivery of current LVR services.     

Canadian research contributions to low-vision rehabilitation

BACKGROUND: Demographic changes likely to occur in the near future and the need for planning to address them are behind the urgent drive to assess present-day provision and utilization of low-vision rehabilitation (LVR) services in the community. Perhaps even more important is the assessment of supporting research work in this field of health care. The purpose of this study, therefore, was to investigate the current involvement of researchers in Canada in the elucidation of the LVR sciences. METHODS: A PubMed search of the MEDLINE database was performed. Publications were identified according to preset criteria and search key words pertinent to various aspects of LVR sciences. Data were collected on the corresponding authors and their affiliations, type of journal and type of study performed, and reported outcome measures. RESULTS: Approximately 1500 papers were reviewed, and 131 that met the preset criteria were included in the study. Medical doctors published most papers (48.1%), followed by optometrists, those with PhDs, occupational therapists, and others; most of the papers (44.3%) were published in ophthalmology journals. Research was performed mainly at Canadian universities (84%), and the findings were published in the last 3 decades. The studies largely concentrated on rehabilitation services and other aspects of vision rehabilitation (55%), whereas studies focusing on the evaluation of tools used for assessment of either visual functions or functional vision were in the minority (45%). INTERPRETATION: The majority of research activity in Canada is university based and involves the medical profession in a leading role, thus affording LVR the appropriate medium for promotion and development of a multidisciplinary approach to outstanding research issues. Only a fraction of current research in LVR (12.2%) deals with outcome measures of the therapeutic interventions aimed at restoring functional vision.     

Vision Rehabilitation of Persons with Age Related Macular Degeneration

As the population of the United States ages, there is an increase in the number of persons with age related macular degeneration (ARMD). Even as new prevention and treatment techniques are developed, the vision loss associated with ARMD may lead to loss of independence and quality of life. Low vision is a rehabilitative process designed to improve visual function and restore independence. This paper is a review of the current research related to low vision in the areas of magnification, contrast and illumination, reading, training, driving and outcomes assessment.     

Low vision aid in exudative macular degeneration treated by photodynamic therapy and thermal laser photocoagulation

To determine the efficacy of low vision rehabilitation (LVR) in patients with age-related macular degeneration (AMD) treated by photodynamic therapy (PDT) compared to those treated by thermal laser photocoagulation (TLP). · METHODS: A retrospective study was performed examining the files of 42 patients (42 eyes) with AMD who had been treated either by TLP (Group 1) and PDT (Group 2). Once AMD was considered to be inactive they underwent visual rehabilitation in the LVR Unit in order to increase their ability for distant and near vision. · RESULTS: Eighteen eyes had received PDT and 24 had received TLP. Average corrected visual acuity after laser therapy was 0.14 in Group 1, and 0.16 in Group 2. No statistically significant differences were found between both groups before and after laser therapy. Both groups showed improvement after LVR; however, statistically significant differences between both groups were found only for near vision. · CONCLUSION: Our findings suggest that even though both PDT and TLP are associated to a decreased visual acuity after treatment, LVR may be more successful for near vision among patients treated by PDT     

白内障手术对年龄相关性黄斑变性的影响

年龄相关性白内障和年龄相关性黄斑变性(age-related macular degeneration,AMD)是导致老年人视力损害的重要眼病,而老年人常会同时患这两种年龄相关性眼病.早期研究认为白内障术后可促进AMD的进展.但随着对疾病的认识逐渐加深以及治疗策略的不断进步,白内障手术是否对AMD有较大影响尚存争议.本文将对两种疾病的发病率、白内障手术治疗与AMD进展的关系,以及如何在白内障手术后有效降低AMD的手术风险进行综述.     

白内障手术能使老年性黄斑变性病情加重吗？

目的调查研究白内障手术是否使早期老年性黄斑变性的病情加剧。方法确诊白内障合并湿性早期年龄相关性黄斑变性60例（60眼）,病例随机分为两组,均进行临床观察6个月。对照组30例观察6个月后行白内障手术;手术组30例,给晶状体超声乳化联合人工晶状体植入术后,与对照组一起观察6个月,观察项目包括：最佳矫正视力、荧光素眼底血管造影。结果在立即手术组中有1例手术眼在术后6个月观察期中出现了脉络膜新生血管（CNV）,对照组在观察期间未发现CNV的出现。手术组的矫正视力较术前平均提高了2.3行以上。结论本次研究中我们观察到：进行白内障手术没有导致湿性早期老年性黄斑变性病情加剧。