Visual impairment (VI) is common among people with intellectual disabilities, with rates up to 19%. This study assessed the prevalence and risk factors for ocular disorders in 341 institutionalised adults with intellectual disabilities in Taipei City from January 2016 to December 2017. The cross-sectional survey included visual acuity testing, cycloplegic refraction, strabismus evaluation, slit-lamp biomicroscopy, tonometry, and retinal exams. Most participants were aged 20-39 years (72.9%), and 57.6% were male. VI or blindness was found in 19.7%, with strabismus (28.0%) and high myopia (23.6%) as key risk factors. Logistic regression indicated strabismus and high myopia significantly increased VI risk (OR 2.32 and 4.86). In participants with Down syndrome, the strabismus-VI association was stronger (OR 4.83 vs 1.73 without DS), with an interactive effect increasing VI risk sixfold. Early ocular screening and targeted interventions are crucial to reduce VI risk in adults with intellectual disabilities.