Affiliations: [a] Laboratory of Vision, Attention and Action, École d’optométrie, Université de Montréal, Montreal, Quebec, Canada
| [b] Département de psychologie, Université de Montréal, Montreal, Quebec, Canada
| [c] Centre interdisciplinaire de recherche sur le cerveau et l’apprentissage, Université de Montréal, Montreal, Quebec, Canada
Correspondence:
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Corresponding author: Aarlenne Zein Khan, École d’optométrie, 2nd floor, 3744 Rue Jean Brillant, Montreal, QC, H3T 1P1, Canada. Tel.: +1 514 343 6111 #4571; E-mail: aarlenne.khan@umontreal.ca.
Abstract: Background:Central vision loss, such as in the case of age-related macular degeneration (AMD), has a a major negative impact on patients’ quality of life. However, some patients have shown spontaneous adaptive strategies development, mostly relying on their peripheral vision. Objective:This study assesses eye movement and eccentric visual function adaptive behaviors of a healthy population in the presence of simulated central vision loss. We wished to determine how central vision loss affects eye movements, specifically the foveal-target alignment. Methods:Fifteen healthy participants (7 females, M = 21.69, SD = 2.13) discriminated the orientation of a Gabor relative to the vertical located at 12 deg of eccentricity to the right of fixation, in the presence of a gaze-contingent artificial central scotoma either visible or invisible. The artificial central scotoma was 4° diameter in order to simulate an earlier stage of degenerative disease while still impairing foveal vision. The target’s orientation varied between 10° counter-clockwise and 10° clockwise. Each participant performed four blocks of 75 trials each per day over 10 days, the first day being a baseline without scotoma. Results:We found changes in the endpoints of the 1st saccade over the practice days. The most common pattern was a gradual upward shift. We also observed a significant increase in discrimination performance over the 9 days of practice. We did not find any difference linked to the scotoma types. Conclusions:These findings suggest that the presence of an artificial central scotoma combined with a challenging discrimination task induces both changes in saccade planning mechanisms, resulting in a new eccentric-target alignment, and improvements in eccentric visual functions. This demonstrates the potential of this research paradigm to understand and potentially improve visual function in patients with central vision loss.
Keywords: Age macular degeneration, preferred retinal locus, attentional shift, central vision loss, vision loss adaptation
