Reduction of retinal nerve fibre layer (RNFL) thickness has been reported in neurodegenerative conditions, including inherited ataxias and hereditary spastic paraparesis. Mutations in SPG7 are increasingly identified as a common cause of spastic ataxia.

Spectral domain optical coherence tomography (OCT) was performed in 25 individuals (six females) with genetically confirmed SPG7-related spastic ataxia to quantify peripapillary RNFL thickness. Standardized examination included age of onset, mean: 40 years (range 12–61); disease duration, mean: 19.6 years (range 6–42 years) and disease severity as quantified with Scale for the Assessment and Rating of Ataxia (SARA), mean: 10.2/40 (range 3–29).

Abnormal RNFL thickness in comparison to controls was detected in 12/22 patients. 3/12 patients had disease duration of less than 10 years and demonstrated predominantly temporal inferior RNFL loss. There was no significant correlation between global RNFL thickness with disease severity (R=-0.13, p=0.75) or disease duration (R=-0.31, p=0.41).

RNFL abnormalities in patients with spastic paraparesis/ataxia may be suggestive of SPG7-associated disease. OCT, non-invasive and quick, should be considered part of the neurological assessment, especially in patients with late-onset spastic ataxias. Further longitudinal studies are needed to determine whether RNFL thickness could be used as a potential biomarker for disease progression in the SPG7 cohort.