[Anterior segment changes in mucopolysaccharidoses]

Mucopolysaccharidoses (MPS) are rare lysosomal storage disorders in which the accumulation of undegraded glycosaminoglycans leads to progressive multiorgan and ocular changes. The anterior segment of the eye is particularly affected, with type-specific, distinct corneal and chamber angle alterations. The aim of this study was to characterize anterior segment changes in different MPS types based on structural and functional examinations using clinical and imaging parameters.

In a clinical cross-sectional study, patients with MPS (types I, II, III, IV, VI) were compared with an age-matched control group. Data collection included general ophthalmic and orthoptic examinations, slit-lamp findings, anterior segment Scheimpflug imaging with the Oculus Pentacam® HR, optical biometry using the IOLMaster 700 and the anterior segment module of the SPECTRALIS® OCT (AS-OCT) for chamber angle assessment.

A total of 58 eyes from 29 MPS patients and 58 eyes from healthy controls were analyzed. The MPS group was predominantly male patients (72.4%), whereas the control group was predominantly female (65.5%). The median age was 21 years (interquartile range, IQR 14-32) and 23 years (IQR 13-34), respectively. Best-corrected visual acuity was significantly reduced in MPS patients (median: 0.3 logMAR vs. -0.1 logMAR; p < 0.001). Stromal corneal opacities were observed in 44.8% of MPS eyes, predominantly in types I, IV and VI. Intraocular pressure was elevated (median: 16 mm Hg vs. 12 mm Hg; p < 0,001) without glaucomatous visual field defects or optic nerve head changes. The anterior chamber depth was significantly reduced (median: 3.0 mm vs. 3.5 mm; p < 0.001), as were anterior chamber angle parameters (ACA/AOD; both p < 0.001), particularly in MPS types I, II and VI.

Anterior segment morphology in MPS patients shows distinct type-specific pathological changes. Pentacam, IOL Master, and AS-OCT are suitable tools for detecting structural changes. Structured ophthalmological examinations can detect typical alterations in patients with MPS and enable early identification of changes.