# Retinal microstructual and microvascular changes in mucopolysaccharidoses

## TL;DR

This study shows that people with mucopolysaccharidoses (MPS) have significant eye problems, including worse vision and retinal changes, compared to healthy individuals.

## Contribution

The study provides the first quantitative OCT images in MPS III patients and identifies subtype-specific retinal and optic disc changes.

## Key findings

- MPS patients had significantly worse visual acuity and higher intraocular pressure compared to controls.
- OCT-A showed reduced capillary density in the retina of several MPS subtypes.
- Quantitative OCT images in MPS III patients revealed the most severe retinopathy.

## Abstract

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.

Depending on the subtype, MPS patients show different pathological changes in the posterior segment of the eye, including pigmentary retinopathy, and optic disc edema or atrophy.

Depending on the subtype, MPS patients show different pathological changes in the posterior segment of the eye, including pigmentary retinopathy, and optic disc edema or atrophy.

Both funduscopy and imaging revealed changes in the posterior segment of the eye, particularly in MPS type II, with significant thinning of the retina in the parafoveal and perifoveal regions.For the first time, quantitative OCT images were obtained in MPS III patients, who have the most severe form of retinopathy according to literature, providing a basis for further studies. In several MPS subtypes, OCT angiography showed a reduced capillary density and HMM images demonstrated a reduction of cone photoreceptors.

Both funduscopy and imaging revealed changes in the posterior segment of the eye, particularly in MPS type II, with significant thinning of the retina in the parafoveal and perifoveal regions.

For the first time, quantitative OCT images were obtained in MPS III patients, who have the most severe form of retinopathy according to literature, providing a basis for further studies.

In several MPS subtypes, OCT angiography showed a reduced capillary density and HMM images demonstrated a reduction of cone photoreceptors.