Distant visual acuity in chronic psychiatric patients. A pilot study

Background: There is a paucity of systematically collected data on visual impairment in patients with chronic psychiatric disorders. The aim of this pilot study was to estimate the magnitude of impairment of distant visual acuity (DVA) including refractive and non-refractive errors in institutionalized psychiatric patients awaiting resettlement in the community in Hong Kong. Method: DVA was tested using the Snellen method in a randomly selected cohort of 428 institutionalized psychiatric patients from the four long-stay rehabilitation units in Hong Kong. The pinhole method was employed to differentiate between refractive and non-refractive impairment of DVA. Results: Seventy-five percent of the sample had impaired DVA; 39 % of the subjects had refractive error (myopia). Only a small percentage of patients wore spectacles and had adequately corrected vision. Patients with impaired DVA were significantly older than those with normal DVA. Conclusion: While the frequency of myopia corresponds to that found in the general population in Hong Kong, the nature of non-refractive impairment needs further investigation including systematic eye examination, and examination of medication and life-style factors. Periodical eye examinations should be part of comprehensive health assessment for chronic psychiatric patients. Accepted: 27 May 2002