Objective quantification of changes in corneal clouding over time in patients with mucopolysaccharidosis

PURPOSE. We determine objective changes in corneal opacification levels over time in patients with mucopolysaccharidoses (MPS) treated with enzyme replacement therapy or hematopoietic stem cell transplant. A prospective cohort study was done of 9 patients with MPS I (Hurler) or VI (Maroteaux-Lamy). METHODS. Quantification of corneal clouding using the Iris camera and full ophthalmic examination, including subjective assessment of corneal clouding, was done in 2011 and repeated in 2015/2016. Patients also had assessment of biomarkers, including dermatan sulfate/chondroitin sulfate (DS/CS) ratio. Change in corneal opacification were measured by Iris camera corneal opacification measure (COM) score during a mean of 60 months followup. RESULTS. A total of 5/17 (29%) eyes had a deterioration in COM score, indicating increased corneal clouding. There was no significant change in COM score in 10/17 (59%) patient eyes. One patient (2/17 eyes) demonstrated significant improvement in corneal clarity and this was associated with improved biomarker levels. CONCLUSIONS. Assessment of COM scores using the Iris camera are an objective means of monitoring corneal opacification over time in patients with MPS. Corneal opacification may potentially be reversed with intensive treatment demonstrated by impact on biomarkers.