Neuroretinal structure changes in infantile nephropathic cystinosis

Area of Science:

• Ophthalmology
• Genetics
• Metabolic Diseases

Background:

• Cystinosis is a lysosomal storage disease characterized by cystine crystal accumulation.
• Ocular manifestations of cystinosis are well-documented, particularly corneal crystal deposits.
• The neuroretinal structure in cystinosis has not been extensively investigated.

Purpose of the Study:

• To investigate the neuroretinal structure in patients with cystinosis.
• To analyze optic disc and macular changes using optical coherence tomography (OCT).
• To compare ocular findings in cystinosis patients with healthy controls.

Main Methods:

• Retrospective cross-sectional analysis of 40 cystinosis patients and 30 healthy controls.
• Optical coherence tomography (OCT) was used to measure peripapillary retinal nerve fiber layer (pRNFL), optic disc volumes, prelaminar depth, and macular ganglion cell layer (mGCL) volumes.
• Measurements were compared between the cystinosis group and an age- and spherical equivalent (SE)-matched control group.

Main Results:

• All cystinosis patients showed pronounced optic disc crystal deposition in a pearl-string pattern.
• The cystinosis group exhibited a significantly thicker pRNFL (839.7 ± 151.0 μm vs. 775.7 ± 79.6 μm, p=0.004).
• A significantly smaller mGCL volume was observed in cystinosis patients (0.25 ± 0.03 mm³ vs. 0.35 ± 0.03 mm³, p=0.036).

Conclusions:

• Cystinosis causes early and pronounced optic disc crystal accumulation, suggesting glial localization.
• Thicker pRNFL and increased positive prelaminar depth in OCT scans contribute to optic disc crowding in cystinosis.
• Significant retinal neurodegeneration, evidenced by GCL thinning, occurs in cystinosis patients, potentially due to metabolic factors.