Longitudinal Study of the Ocular Phenotype in Mucopolysaccharidosis
Krishanthy A. Sornalingam, MBBS; Tariq Aslam, PhD, FRCOphth; Jane Ashworth, PhD, FRCOphth
Manchester Royal Eye Hospital
Manchester, England, United Kingdom
Introduction: The mucopolysaccharidoses (MPSs) are a heterogeneous group of lysosomal storage disorders. Ocular features include corneal clouding, retinopathy, glaucoma and optic atrophy. Treatments have greatly improved systemic outcomes, yet there is limited understanding of their effect on the eye. We aim to longitudinally study the ocular phenotype in MPS, using objective and clinical measures of eye disease.
Methods: Prospective observational cohort study, recruiting from Paediatric Ophthalmology clinics at a single tertiary referral centre. Participants underwent ocular examination including visual acuity, assessment of corneal clouding (Iris Camera Corneal Opacification Measure (COM) score, Pentacam densitometry), and retinal and optic nerve imaging (optical coherence tomography and wide-field fundus imaging). Data on delivered therapies was also collected. Patients were followed up at 4-12 month intervals.
Results: Follow up data within 13 months of the initial review was collected for 20 patients (12 MPSI, 4 MPSIV and 4 MPSVI). 12 patients were on Enzyme Replacement Therapy, 7 were post Haematopoietic Stem Cell Transplantation and 1 had no treatment. During this period, median visual acuity was found to decrease for MPSI and MPSVI groups, but improved in MPSIV. No significant change in IOP was seen. Median COM scores were found increase in all groups. Optos (n=2) and OCT (n=2) findings were stable over the follow-up period.
Discussion: The severity of corneal clouding increased over time in all subtypes of MPS and this was not influenced by systemic treatment.
Conclusion: Objective measurements of ocular phenotype in MPS over time will increase our understanding of the effect of systemic treatments on the eye.