Central Visual Attention in Primary Open-angle Glaucoma

Abstract

Significance To better understand the implication of a potential cognitive change in glaucoma, patients were stimulated in central visual areas considered functionally normal to discard an effect due to the loss of vision during an attentional task. The outcome might improve the follow-up on the impact of the pathology. Purpose This study aimed to evaluate the effect of primary open-angle glaucoma on the visual attention system by recording responses of behavioral and oculomotor strategies. Methods We included 20 individuals with primary open-angle glaucoma (62.1 ± 7.2 years old), 18 age-matched controls (58.4 ± 7.2 years old) and 20 young controls (25.7 ± 3.5 years old). The procedure consisted of visual (eye-tracking recordings) and manual detection of a target. All participants had to detect a square with a vertical bar within distractors (squares, triangles and circles with a horizontal or vertical bar) of identical size of 1.6x1.6° visual angle. The shapes were displayed concentrically on a radius of 5° of visual angle. All participants were tested to ensure that their visual field sensitivity was normal within ±5° central vision. Results In responding manually, glaucoma participants were slower than aged-matched controls ((1723 ± 488 ms vs 1263 ± 385 ms) p < .01). Eye-tracking recordings showed that glaucoma participants found the target within the same timeframe as age-matched controls. Compared to the young group, the scanpath length and average fixation duration on distractors were significantly longer for the glaucoma patients (+235 pixels, +104 ms) and the aged-matched control participants (+120 pixels, +39 ms). Impaired contrast sensitivity was correlated with longer response time, longer scanpath and longer fixation on distractors. Conclusions Glaucoma affects the manual response times in a visual attention task, but patients can visually detect the target as quickly as age-matched controls. Different clinical factors predicted the performances. The age of the patients was associated with longer scanpath. The visual field loss (mean deviation - MD) was linked with longer visual response time. The loss of contrast sensitivity predicted the behavioral change on fixation duration to the distractors, global response time, visual response time and scanpath length.”