Taylor John, Bambrick Rachel, Dutton Michelle, Harper Robert, Ryan Barbara, Tudor-Edwards Rhiannon, Waterman Heather, Whitaker Chris, Dickinson Chris
Faculty of Life Sciences, The University of Manchester, Manchester, UK.
Ophthalmic Physiol Opt. 2014 Sep;34(5):558-72. doi: 10.1111/opo.12149. Epub 2014 Aug 13.
To describe the study design and methodology for the p-EVES study, a trial designed to determine the effectiveness, cost-effectiveness and acceptability of portable Electronic Vision Enhancement System (p-EVES) devices and conventional optical low vision aids (LVAs) for near tasks in people with low vision.
The p-EVES study is a prospective two-arm randomised cross-over trial to test the hypothesis that, in comparison to optical LVAs, p-EVES can be: used for longer duration; used for a wider range of tasks than a single optical LVA and/or enable users to do tasks that they were not able to do with optical LVAs; allow faster performance of instrumental activities of daily living; and allow faster reading. A total of 100 adult participants with visual impairment are currently being recruited from Manchester Royal Eye Hospital and randomised into either Group 1 (receiving the two interventions A and B in the order AB), or Group 2 (receiving the two interventions in the order BA). Intervention A is a 2-month period with conventional optical LVAs and a p-EVES device, and intervention B is a 2-month period with conventional optical LVAs only.
The study adopts a mixed methods approach encompassing a broad range of outcome measures. The results will be obtained from the following primary outcome measures: Manchester Low Vision Questionnaire, capturing device 'usage' data (which devices are used, number of times, for what purposes, and for how long) and the MNRead test, measuring threshold print size, critical print size, and acuity reserve in addition to reading speed at high (≈90%) contrast. Results will also be obtained from a series of secondary outcome measures which include: assessment of timed instrumental activities of daily living and a 'near vision' visual functioning questionnaire. A companion qualitative study will permit comparison of results on how, where, and under what circumstances, p-EVES devices and LVAs are used in daily life. A health economic evaluation will provide results on: the incremental cost-effectiveness of p-EVES compared to optical magnifiers; cost-effectiveness; and cost-utility.
The evidence base in low vision rehabilitation is modest and further high quality clinical trials are required to inform decisions on healthcare provision. The p-EVES study findings are anticipated to contribute to this broader evidence requirement, with the methodological issues evident here being relevant to other trials within the field.
描述p-EVES研究的研究设计和方法，该试验旨在确定便携式电子视力增强系统（p-EVES）设备和传统光学低视力辅助器具（LVA）对低视力患者近距任务的有效性、成本效益和可接受性。
p-EVES研究是一项前瞻性双臂随机交叉试验，旨在检验以下假设：与光学LVA相比，p-EVES可以：使用时间更长；可用于比单一光学LVA更广泛的任务范围和/或使使用者能够完成他们使用光学LVA无法完成的任务；使日常生活中的工具性活动执行得更快；以及阅读速度更快。目前正在从曼彻斯特皇家眼科医院招募100名成年视力障碍参与者，并随机分为第1组（按AB顺序接受两种干预措施A和B）或第2组（按BA顺序接受两种干预措施）。干预措施A是使用传统光学LVA和p-EVES设备的2个月时期，干预措施B是仅使用传统光学LVA的2个月时期。
该研究采用混合方法，涵盖广泛的结局指标。结果将从以下主要结局指标中获得：曼彻斯特低视力问卷，获取设备“使用”数据（使用了哪些设备、使用次数、用途和使用时长）以及MNRead测试，除了测量高对比度（约90%）下的阅读速度外，还测量阈值印刷字体大小、临界印刷字体大小和视力储备。结果还将从一系列次要结局指标中获得，包括：对日常生活中定时工具性活动的评估和一份“近视力”视觉功能问卷。一项配套的定性研究将比较关于p-EVES设备和LVA在日常生活中的使用方式、地点和情况的结果。一项健康经济评估将提供以下结果：p-EVES与光学放大镜相比的增量成本效益；成本效益；以及成本效用。
低视力康复的证据基础有限，需要进一步开展高质量的临床试验，为医疗保健提供决策提供依据。预计p-EVES研究结果将有助于满足这一更广泛的证据需求，此处明显的方法学问题与该领域的其他试验相关。
