The prevalence and causes of visual impairment among the male homeless population of Montreal, Canada

Abstract

Clinical relevance: Homeless populations have lower health indicators, including in eye care. Few data exist on the levels and causes of visual impairment in Canadian homeless populations, and none in Montreal.

Background: This study aims to characterise the causes and levels of visual impairment, as well as eye care services utilisation among the Montreal homeless.

Methods: Using random sampling, five homeless shelters were selected. In each shelter, 20 participants were randomly selected. After obtaining informed consent, participants completed an ocular examination, which included: presenting visual acuity (pinhole as needed), intraocular pressure, confrontation visual field, dilated fundus examination, post-dilation autorefraction and questionnaire on social determinants of health.

Results: A total of 95 participants were examined, of which 97.9% were male. The median age was 49 years old (interquartile range 38-56.5). The age-adjusted prevalence of visual impairment (presenting visual acuity <6/12) was 23.6% (95% CI 15.1-32.9) compared to 6.0% in the Canadian population (Z = 77.9, p < 0.0001). With pinhole correction, the prevalence of visual impairment dropped to 5.8% (95% CI 1.7-11.8). Prevalence was 8.2% (95% CI 3.7-15.9) for cataracts, 11.4% (95% CI 5.9-19.7) for glaucoma or suspects and 4.7% (95% CI 1.7-11.9) for diabetic retinopathy. Lastly, 18.9% of participants had an ocular examination within the last year compared to 41.4% in Canada (Z = -4.5, p < 0.0001) and 13.7% had never had a comprehensive eye examination.

Conclusions: This sample population shows a prevalence of visual impairment which is four times that of the general Canadian population, with highly prevalent uncorrected refractive error, while accessing primary eye care twice less often.

Keywords: Canada; Health services utilisation; homeless persons; refractive errors; visual impairment.