Retinal microstructual and microvascular changes in mucopolysaccharidoses

To analyse ocular manifestations of MPS in the posterior segment of the eye, in particular retinal and optic disc pathologies, compared to healthy controls.

This prospective study analyzed structural and functional posterior eye changes in 29 MPS patients (58 eyes) compared to 29 healthy, age- and gender-matched controls. Examinations included visual acuity testing, orthoptic status, intraocular pressure (IOP) measurement, visual field testing, slit-lamp examination and fundus examination, Spectral-Domain Optical Coherence Tomography (SD-OCT), OCT-Angiography (OCT-A) and High Magnification Module^® (HMM^®) imaging.

LogMAR visual acuity (p < 0.001) and IOP (p < 0.001) were significantly worse/higher in MPS patients. Visual field defects showed a concentric restriction pattern, resembling to pigmentary retinopathy. Fundus examination of 56 eyes revealed optic disc atrophy in two eyes (all MPS II), atrophic macula in two eyes (both MPS II) and pigmentary retinopathy in twelve eyes (6 MPS II, 6 MPS IV). Total retinal thickness was significantly reduced in the parafoveal (p < 0.001) and perifoveal (p < 0.001) macula area in MPS, especially in MPS II patients. Peripapillary retinal nerve fiber layer thickness correlated positively with IOP (p = 0,015) in the MPS group. OCT-A findings revealed reduced capillary density of the parafoveal and perifoveal retina in 8/22 eyes in the MPS group (2 MPS I, 4 MPS II, 2 MPS IV). Rarefaction of the photoreceptor mosaic was observed in some MPS patients on HMM imaging.

MPS patients exhibit impaired visual acuity and visual fields, higher IOP, and mircostructural and microvascular alterations of the optic disc and retina compared to healthy subjects.