Department of Optometry and Visual Science, City University London, London, United Kingdom.
PLoS One. 2010 Mar 16;5(3):e9710. doi: 10.1371/journal.pone.0009710.
Glaucoma is a progressive eye disease and a leading cause of visual disability. Automated assessment of the visual field determines the different stages in the disease process: it would be desirable to link these measurements taken in the clinic with patient's actual function, or establish if patients compensate for their restricted field of view when performing everyday tasks. Hence, this study investigated eye movements in glaucomatous patients when viewing driving scenes in a hazard perception test (HPT).
METHODOLOGY/PRINCIPAL FINDINGS: The HPT is a component of the UK driving licence test consisting of a series of short film clips of various traffic scenes viewed from the driver's perspective each containing hazardous situations that require the camera car to change direction or slow down. Data from nine glaucomatous patients with binocular visual field defects and ten age-matched control subjects were considered (all experienced drivers). Each subject viewed 26 different films with eye movements simultaneously monitored by an eye tracker. Computer software was purpose written to pre-process the data, co-register it to the film clips and to quantify eye movements and point-of-regard (using a dynamic bivariate contour ellipse analysis). On average, and across all HPT films, patients exhibited different eye movement characteristics to controls making, for example, significantly more saccades (P<0.001; 95% confidence interval for mean increase: 9.2 to 22.4%). Whilst the average region of 'point-of-regard' of the patients did not differ significantly from the controls, there were revealing cases where patients failed to see a hazard in relation to their binocular visual field defect.
CONCLUSIONS/SIGNIFICANCE: Characteristics of eye movement patterns in patients with bilateral glaucoma can differ significantly from age-matched controls when viewing a traffic scene. Further studies of eye movements made by glaucomatous patients could provide useful information about the definition of the visual field component required for fitness to drive.
青光眼是一种进行性眼病，也是导致视力残疾的主要原因。自动评估视野可以确定疾病进程的不同阶段：理想情况下，将这些在诊所中获得的测量结果与患者的实际功能联系起来，或者确定患者在执行日常任务时是否会补偿其视野受限的问题。因此，本研究通过在危险感知测试（HPT）中观察驾驶场景，调查了青光眼患者的眼动情况。
方法/主要发现：HPT 是英国驾驶执照考试的一部分，由一系列从驾驶员视角观看的各种交通场景的短片组成，每个场景都包含需要改变方向或减速的危险情况。考虑了九名患有双眼视野缺损的青光眼患者和十名年龄匹配的对照组患者的数据（均为有经验的驾驶员）。每个受试者观看了 26 个不同的电影，同时通过眼动追踪器监测眼动。编写了专用的计算机软件来预处理数据，将其与电影剪辑进行配准，并量化眼动和注视点（使用动态双变量轮廓椭圆分析）。平均而言，并且在所有 HPT 电影中，患者的眼动特征与对照组不同，例如，患者的扫视次数明显更多（P<0.001；平均值的置信区间为 9.2 到 22.4%）。尽管患者的“注视点”平均区域与对照组没有显著差异，但有一些明显的情况表明，患者在与他们的双眼视野缺损相关的情况下未能看到危险。
结论/意义：当观看交通场景时，患有双侧青光眼的患者的眼动模式特征可能与年龄匹配的对照组有很大的不同。对青光眼患者的眼动进一步研究可以提供有关适合驾驶所需的视野组成部分的定义的有用信息。
