Purpose.Maroteaux–Lamy syndrome is one of the mucopolysaccharidoses caused by enzyme deficiency (arylsulfatase B) that leads to incomplete degradation and storage of dermatan sulfate. We report a case of mucopolysaccharidosis type VI (MPS VI; Maroteaux–Lamy syndrome) with corneal involvement and introduce ultrasound biomicroscopy (UBM) as an examination with which to follow disease progression in relation to deposition in cornea, angle, and iris.Methods.We describe a 11-year-old boy with a clinical and laboratorial diagnosis of MPS VI who developed increasing bilateral corneal opacification and decreased visual acuity. He underwent two seriate UBM (50-MHz transducer) evaluations.Results.UBM examination showed diffuse and homogeneous stromal hyper-reflective deposit in both eyes and an increase in peripheral corneal thickness throughout time.Conclusion.High-frequency ultrasound documentation of corneal deposit and anterior segment involvement in a patient with Maroteaux–Lamy syndrome is unique, and follow-up revealed thickening of the corneal periphery, which may be related to the progression of the disease (continuous mucopolysaccharide deposits in corneal stroma). UBM was used to locate and document the deposit, as well as to accompany the deposit's evolution, characterizing corneal changes and angle structure involvement.