Background: Mucopolysaccharidoses (MPSs) are a class of rare lysosomal storage disorders marked by the accumulation of glycosaminoglycans in numerous organs and tissues. These patients frequently experience ocular disorders, including the optic nerve, retina, trabecular mes-hwork, cornea, and sclera. Objectives: Assessment of the incidence of ophthalmic manifestations in cases with MPSs and the effect of enzymatic replacement on the ophthalmic manifestations among those patients. Methods: All patients under 18 years old with any type of MPSs demo-nstrated by the enzymatic assay and attended to the Outpatient General Clinics or the Metabolic Unit of Assiut University Children Hospital during the study period were enrolled in the current study. The results of ophthalmologic examinations were recorded, including visual acuity, lens opacity, refractive errors (such as astigmatism, myopia, and hyperopia), and, if feasible, intraocular pressure (IOP) measurement. Results: Among 30 MPSs confirmed patients, 43.3% of those with MPS I, 16.7% with MPS II, 33.3% with MPS Ⅳ, and 6.7% with MPS Ⅵ. The majority of the studied cases (73.3%) suffered from the error of refraction, mainly hypermetrope, 83.3% had corneal affection, and the ciliary body and iris were affected in almost all studied cases (93.3%). High intraocular pressure was observed in 30.0%, and the eye lens in the form of cataract was affected in ten cases (33.3%). However, the posterior segment was free in all cases except one case that suffered from glaucomatous cupping. Conclusion: Patients with MPS frequently experience ocular problems that result in a marked decline in visual acuity.