Taylor Deanna J, Smith Nicholas D, Crabb David P
Division of Optometry and Visual Science, School of Health Sciences, City, University of London, London, United Kingdom.
Invest Ophthalmol Vis Sci. 2017 Mar 1;58(3):1887-1892. doi: 10.1167/iovs.16-21122.
Treatment success in clinical trials for AMD would ideally be aligned to measurable performance in visual tasks rather than imperceptible changes on clinical charts. We test the hypothesis that patients with dry AMD perform worse than visually healthy peers on computer-based surrogates of "real-world" visual search tasks.
A prospective case-control study was conducted in which patients with dry AMD performed a computer-based "real-world" visual search task. Participants searched for targets within images of everyday scenes while eye movements were recorded. Average search times across the images were recorded as a primary outcome measure. Comparisons were made against a 90% normative limit established in peers with healthy vision (controls). Eye movement parameters were examined as a secondary outcome measure.
Thirty-one patients and 33 controls with median (interquartile range) age of 75 (70-79) and 71 (66-75) years and logMAR binocular visual acuity 0.2 (0.18-0.31) and -0.06 (-0.12 to 0), respectively, were examined. Four, 18, and 9 patients were categorized as having early, intermediate, and late AMD, respectively. Nineteen (61%) patients exceeded the 90% normative limits for average search time; this was statistically significant (Fisher's exact test, P < 0.0001). On average, patients made smaller saccades than controls (P < 0.001).
People with dry AMD, certainly those with advanced disease, are likely to have measurable difficulties beyond those observed in visually healthy peers on "real-world" search tasks. Further work might establish this type of task as a useful outcome measure for clinical trials.
理想情况下，年龄相关性黄斑变性（AMD）临床试验中的治疗成功应与视觉任务中可测量的表现相关，而非临床图表上难以察觉的变化。我们检验了这样一个假设：干性AMD患者在基于计算机的“现实世界”视觉搜索任务替代指标上的表现比视力正常的同龄人差。
进行了一项前瞻性病例对照研究，干性AMD患者执行基于计算机的“现实世界”视觉搜索任务。参与者在日常场景图像中搜索目标，同时记录眼动情况。记录所有图像的平均搜索时间作为主要结局指标。与视力正常的同龄人（对照组）建立的90%正常范围进行比较。将眼动参数作为次要结局指标进行检查。
共检查了31例患者和33例对照，患者和对照的年龄中位数（四分位间距）分别为75（70 - 79）岁和71（66 - 75）岁，双眼最小分辨角对数视力分别为0.2（0.18 - 0.31）和 - 0.06（ - 0.12至0）。分别有4例、18例和9例患者被分类为早期、中期和晚期AMD。19例（61%）患者的平均搜索时间超过了90%正常范围；这具有统计学意义（Fisher精确检验，P < 0.0001）。平均而言，患者的扫视幅度小于对照组（P < 0.001）。
干性AMD患者，尤其是那些患有晚期疾病的患者，在“现实世界”搜索任务中可能存在比视力正常的同龄人更明显的可测量困难。进一步的研究可能会将这类任务确立为临床试验中一种有用的结局指标。
