Optical coherence tomography and visual field findings in patients with Friedreich ataxia

Abstract

Background: To investigate the optical coherence tomography (OCT) and visual field findings in Friedreich ataxia (FRDA).

Methods: Ten eyes of 10 patients with genetically confirmed FRDA were included in this study. Twenty-two eyes of 22 age- and sex-matched volunteers served as controls. All eyes were examined with spectral domain OCT (Retinascan Advanced RS-3000; NIDEK) and Humphrey Field Analyzer (HFA II 750; Zeiss-Humphrey Systems).

Results: OCT measurements of the average peripapillary retinal nerve fiber layer (RNFL) thickness, average peripapillary retinal thickness (RT), and foveal RT showed a statistically significant reduction in patients with FRDA (P < 0.0001). There was no statistically significant difference in choroidal thickness. OCT measurements of horizontal cup-to-disc (C/D) ratio, vertical C/D ratio, and average cup area were significantly increased in patients with FRDA. Visual acuity was significantly correlated with age at onset (P = 0.021) and average RNFL value (P = 0.045). There was a significant correlation between foveal thickness and disease duration (P = 0.014). Mean RNFL thickness was significantly correlated with the severity of neurological involvement (P = 0.039). Visual field testing (VFT) revealed a generalized reduction of sensitivity in the patients.

Conclusion: Patients with FRDA may have a measurable degree of retinal thinning as determined by OCT and a generalized reduction of sensitivity in VFT. Combining structural and functional findings may be used in the follow-up of patients with FRDA.