purpose: the objective of this study was to determine the prevalence and severity of ocular complications in patients with mucopolysaccharidosis (mps). methods: twenty-nine patients with diagnosis of mucopolysaccharidosis were studied. age, gender, visual acuity, presence of strabismus, refractive error, fundus examination, intraocular pressure, central corneal thickness and ocular echography were assessed for each individual. results: there were three patients with mps i (12%), eleven patients with mps ii (37.9%), one patient with mps iii (3.4%) and fourteen patients with mps vi (48.3%). mean age was 9.5 years (ranged from 1.2 to 20 years, dp 5.5). refraction was available in 26 patients, from which 88.5% (23 patients) were hyperopic, and 53.8% (14 patients) presented astigmatism. best corrected visual acuity was available in 18 patients and the mean was 0.45 logmar (dp 0.68). the mean spherical equivalent was +3.57 d (sd 2.46) and intraocular pressure was 17 mmhg (sd 3.9). the most common findings were: eyelid thickening in 24.1% (7 patients); corneal opacity in 55.2% of cases (16 patients); optic nerve atrophy in 23.1% (6 patients); and radial folds in the retina in 24% (7 patients). the fundus was examined in 26 out of 29 patients because corneal opacity avoided the exam in 3 of them. the average thickness of the complex sclera-retina-choroid (src was 1.78 mm (sd 0.51). conclusion: the most prominent ophthalmologic findings were eyelid thickening, decreased visual acuity, high hyperopia, corneal opacity, perimacular radial folds in the retina and optic nerve atrophy.