Background: 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. Method: The cross-sectional survey included visual acuity testing, cycloplegic refraction, strabismus evaluation, slit-lamp biomicroscopy, tonometry, and retinal exams. Results: 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. Conclusion: Early ocular screening and targeted interventions are crucial to reduce VI risk in adults with intellectual disabilities.