Researchers evaluated 388 blind subjects and 44 sighted subjects by interview and questionnaire. Sleep disturbance was reported by 48.7% of blind subjects, with the prevalence and degree of problems being higher in those with no light perception than in those with light perception or better visual acuity. In the comparison group, 9.1% of people reported mild sleep problems.

The researchers suggest that treatment for insomnia may improve quality of life for these people.