Abstract
Purpose: :
To report spectral-domain optical coherence tomography (SD-OCT) findings in order to detect subclinical alterations of the afferent visual pathways in spinocerebellar ataxia 3 (SCA-3). To provide correlation between an anatomic marker, including retinal nerve fiber layer (RNFL) and macular thickness, and the scale for the assessment and rating of ataxia (SARA score) and the duration of the ataxia.
Methods: :
9 genetically confirmed patients (18 eyes) were evaluated with a complete ophthalmologic examination including visual acuity, colour vision, visual field test, and RNFL and macular thickness with SD-OCT. Neurological examination was performed and SARA score was determined.
Results: :
Mean RNFL thickness was 77,39 microns, standard deviation (SD) was +/-5,93. In 15 eyes (83,33%) mean RNFL thickness was lower than the population average considering age and sex. In 10 cases there was a reduction of the RNFL thickness in the superior sector, 8 in the inferior and 4 in the nasal. Temporal sector RNFL thickness was preserved in all eyes. Significant negative correlation was found between disease severity (SARA score) and RNFL thickness (r=-0,64, p=0,012). Mean macular thickness was 252,61 microns, SD +/-22,80. Significant negative correlation was found between disease duration and macular thickness (r=-2,79, p=0,032). In 4 patients (8 eyes) OCT studies were performed during a mean follow-up of 14,25 months (ranging from 9 to 24 months), and in 5 eyes (62,50%) there was a mild trend to a RNFL thickness decrease in this period.
Conclusions: :
A mild and progressive decrease in RNFL thickness, without clinical repercussion, can be observed in SCA-3 patients. Due to the significant negative correlation between RNFL thickness and SARA score, RNFL thickness could be considered as a possible marker of the disease severity.
Keywords: neuro-ophthalmology: optic nerve • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual impairment: neuro-ophthalmological disease