Kearns-Sayre syndrome is a rare mitochondrial disorder. It had a triad of features, including progressive external ophthalmoplegia, pigmentary retinopathy, and an alteration of cardiac conduction. The ocular manifestations include bilateral ptosis, progressive external ophthalmoplegia, and atypical pigmentary retinopathy. We report the case of a 9-year-old Moroccan patient who has been diagnosed with Kearns-Sayre syndrome during an ophthalmologic school-based screening. This case highlights the interest of school-based screening in the diagnosis and management of a rare disease.