Background: To estimate the prevalence of visual impairment, and identify its causes and associated factors among adults aged 40 years and over, attending for eye examination at a Riyadh public hospital in Saudi Arabia. Methods: This was a retrospective cross-sectional study conducted among 195 consecutive older adults who attended the outpatient ophthalmology clinic of King Abdul-Aziz University Hospital between 1 February and 30 June 2018. All participants underwent comprehensive ophthalmic examination: visual acuity, refraction (objective and subjective), fundus photography and automated visual field assessment. Classification of visual impairment was based on the World Health Organization criteria: mild visual impairment if best-corrected distance visual acuity < 6/12-6/18 in the better eye; moderate visual impairment if bestcorrected visual acuity < 6/18-6/60 in the better eye; and severe visual impairment if bestcorrected visual acuity < 6/60-3/60. Regression analysis was used to identify the factors associated with visual impairment. Results: The study participants included 107 (54.9 per cent) females, and the mean (SD) age was 61.1 AE 10.9 years. The overall prevalence of visual impairment (14.9 per cent, 29 cases), consisting of severe (0.5 per cent), moderate (9.7 per cent) and mild (4.6 per cent) forms, correlated significantly with age (R 2 = 0.023, p = 0.04). The main causes of visual impairment were glaucoma (48.3 per cent), cataract (31.0 per cent), refractive error, and diabetic retinopathy (24.1 per cent each). The odds of having visual impairment increased by 22 per cent and eight per cent respectively in participants who had diabetic retinopathy (adjusted odds ratio 1.22, 95% confidence interval [CI] 1.05, 1.95) and glaucoma (1.08, CI 1.02, 1.40). Conclusions: The prevalence of visual impairment among older adults attending the ophthalmology clinic in Riyadh city was high and driven by the high rate of diabetic retinopathy and glaucoma in this region. As part of their routine checks, there is need to make dilated fundus examination and intraocular pressure measurement mandatory tests in addition to refraction and visual acuity testing, when examining Saudi adults attending the hospital eye clinics in Riyadh province.