Rapid eye movements are reduced in blind individuals.
Journal of Sleep Research December 1, 2019 Julie A E Christensen, Sébrina Aubin, Tore Nielsen et al.
Rapid eye movements (EMs) during REM sleep are not necessary for visual dream imagery. Blind individuals, both congenitally blind and late blind, showed significantly less eye movement coverage during wakefulness and all sleep stages compared to sighted controls. Late blind subjects reported more visual dream elements than congenitally blind subjects, yet both blind groups had similarly low eye movement activity. The near absence of nocturnal eye movements in late blind subjects, despite preserved visual dream content, does not support the hypothesis that REM sleep eye movements reflect visual scanning of dream imagery. Results indicate a dissociation between eye movements and visual dream content in blind individuals.