Ophthalmological manifestations in a cohort of Cowden syndrome patients in a large tertiary healthcare system What this study adds · In a large U.S. tertiary system (Mass General Brigham), the observed CS prevalence was 1.28 per 100,000— somewhat higher than other prior population-based estimates. · Among 77 confirmed CS patients, only 17 (22%) underwent ophthalmologic evaluation, and 4 patients (≈24% of those examined; 5% of the cohort) had ocular findings potentially related to CS. Visual acuity was mostly excellent and stable over a median ophthalmic follow-up of 4.5 years in this cohort · Potential CS-related ocular findings included retinal hamartomas, an eyelid capillary hemangioma, a trichilemmoma, and a stable peripapillary hamartoma-like lesion/old CNVM. Only one patient had complete multimodal retinal imaging (OCT, FA, OCTA), underscoring limited ophthalmic documentation and the need for standardized eye screening in CS. · Three of the four patients with ocular findings carried truncating PTEN variants, hinting at a possible genotype association that warrants larger, prospective studies. · No distinct ocular phenotype emerged from the cohort plus literature synthesis, reinforcing calls for multicentre prospective work to define ocular risk and screening guidelines in CS. #Cowden @HMSeye #retina #PTEN