Gameiro Ricardo Ramos, Jünemann Kristin, Herbik Anne, Wolff Anika, König Peter, Hoffmann Michael B
Institute of Cognitive Science, University of Osnabrück, Osnabrück, Germany.
Visual Processing Lab, Ophthalmic Department, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
J Vis. 2018 Nov 1;18(12):10. doi: 10.1167/18.12.10.
Retinitis pigmentosa (RP) is an inherited disease that causes progressive peripheral visual-field loss. In this study, we investigated how such loss affects visual exploration of natural images. Individuals with varying degrees of visual-field loss and healthy control participants freely observed images of different sizes while eye movements were recorded. We examined whether visual behavior differed when the scene content was shown in various extents of the visual field, and investigated the spatial bias, saccade amplitudes, and number and duration of fixations. We found that the healthy control group showed a central spatial bias during image viewing. The RP group showed similar biases on the group level, but with reproducible individual exploration patterns. For saccade amplitudes, the healthy control group and the RP group showed similar behavior throughout all image sizes. The RP group with severe loss of peripheral vision thus tended to target saccades toward blind areas of their visual field. The number of fixations did not change between the two groups, although fixation durations decreased in the RP group. In conclusion, the RP group scanned the images surprisingly similarly to the healthy control group; however, they showed individual idiosyncratic explorative strategies when the observed scene exceeded their visible field. Thus, although RP leads to a severe loss of the visual field, there is no general adaptive mechanism to change visual exploration. Instead, individuals rely on individual strategies, leading to high heterogeneity in the RP group.
视网膜色素变性（RP）是一种遗传性疾病，会导致周边视野逐渐丧失。在本研究中，我们调查了这种视野丧失如何影响对自然图像的视觉探索。不同程度视野丧失的个体和健康对照参与者在记录眼动的同时自由观察不同大小的图像。我们检查了当场景内容在视野的不同范围内呈现时视觉行为是否存在差异，并研究了空间偏差、扫视幅度以及注视次数和持续时间。我们发现健康对照组在观看图像时表现出中央空间偏差。RP组在群体水平上表现出类似的偏差，但具有可重复的个体探索模式。对于扫视幅度，健康对照组和RP组在所有图像大小上都表现出类似的行为。因此，周边视力严重丧失的RP组倾向于将扫视目标指向其视野的盲区。两组之间的注视次数没有变化，尽管RP组的注视持续时间减少。总之，RP组对图像的扫描方式与健康对照组惊人地相似；然而，当观察到的场景超出其可见视野时，他们表现出个体特有的探索策略。因此，尽管RP会导致严重的视野丧失，但没有普遍的适应性机制来改变视觉探索。相反，个体依赖于个体策略，导致RP组存在高度异质性。
