Decreased retinal sensitivity and loss of retinal nerve fibers in multiple system atrophy

In a previous study, retinal nerve fiber layer thickness (RNFLT) loss was shown as part of the neurodegenerative process in multiple system atrophy (MSA). Here, we investigate in a larger cohort of MSA patients whether the RNFLT loss translates into respective visual field defects.

Spectral domain optical coherence tomography was performed in 20 MSA patients (parkinsonian subtype = 12, cerebellar subtype = 8) to quantify peripapillary RNFLT. Visual field (90°) was analyzed by automated static perimetry to investigate retinal structure/function relationship. Eight data sets did not meet stringent quality criteria, and only 12 data sets were further analyzed.

Compared to healthy controls, MSA patients demonstrated a significant reduction of RNFLT in the nasal sectors (p ( nasal-superior ) = 0.02, p ( nasal ) = 0.03, p ( nasal-inferior ) < 0.01), while changes in temporal RNFLT measures (p ( temporal-superior ) = 0.42, p ( temporal ) = 0.34, p ( temporal-inferior ) = 0.25) were not statistically significant compared to healthy controls (ANOVA). MSA patients featured a significant global mean deviation (2.74 dB; p < 0.01) without predominant peripheral visual field defects. Statistical analysis of mean defect in the central (0-30°), peripheral (30-90°) or global (0-90°) visual field revealed no significant correlation (r (2) (central) = 0.11, r (2) (peripheral) = 0.04, r (2) (global) = 0.07) with nasal RNFLT in MSA patients.

MSA patients feature significant reduction in nasal RNFLT and global mean deviation when compared to healthy controls, consistent with the multi-systemic nature of this neurodegenerative disorder. This finding provides first evidence for two independent deteriorations of the visual system in MSA.