Assessment of Macular Function in Fabry's Disease Patients With No or Minimal Evidence of Retinal Involvement

Abstract

Purpose: : To evaluate by focal electroretinogram (FERG) macular function in Fabry's disease patients with known genotype and no or minimal evidence of retinal involvement.

Methods: : 24 eyes of 12 Fabry's patients with no signs and symptoms of ocular disease, and 20 eyes of 20 age-matched control subjects were included in the study. Slit-lamp, ophthalmoscopic examination and best corrected visual acuity evaluation were performed. FERGs were recorded in response to 41 Hz sine-wave stimuli presented to the macular region (18 degrees) on a steady light-adapting background. The response fundamental component, isolated by Fourier analysis, was quantified in its amplitude and phase.

Results: : In 4 out of 12 patients, microvascular retinal abnormalities (tortuosity, microaneurysms) were found at ophthalmoscopy. The remaining patients had normal fundus. None of patients had vortex keratopathy ("cornea verticillata"). Mean FERG 41 Hz amplitude was significantly reduced, and mean phase was delayed, in patients compared to control values (p <0.001 - t-tests). All individual patients had mono-or-bilateral FERG abnormalities. No correlation with the presence of microvascular abnormalities was found.

Conclusions: : The results indicate a subclinical impairment of the macular system in visually asymptomatic Fabry's disease patients, supporting the use of FERG as an effective tool for detecting retinal dysfunction early in the disease progression.

Keywords: electroretinography: clinical • degenerations/dystrophies • retina