Circumscribed outer foveolar defects in spinocerebellar ataxia type 7.

OBJECTIVE

To report circumscribed outer foveolar defects in a 40-year-old man with a history of spinocerebellar ataxia type 7.

METHODS

A 40-year-old man with genetically confirmed spinocerebellar ataxia type 7 presented with progressive vision loss and decreased color perception for 3 years. He underwent a full ocular examination, fundus photography, autofluorescence, spectral-domain optical coherence tomography imaging, and a full-field electroretinogram.

RESULTS

The patient's ocular examination and fundus autofluorescence were both normal except for mild temporal pallor of both optic discs. Spectral-domain optical coherence tomographic imaging showed foveal thinning with an outer foveolar defect because of focal loss of photoreceptors, disruption of the inner segment-outer segment junction but preservation of the external limiting membrane, and thinning of the outer plexiform layer in both eyes. Electroretinography showed severely reduced cone function with mildly reduced rod function.

CONCLUSIONS

Spinocerebellar ataxia type 7 should be included in the differential diagnosis for "outer retinal holes" or "foveal cavitation," which also includes solar retinopathy, juxtafoveal telangiectasia, Welder maculopathy, tamoxifen retinopathy, Stargardt disease, amyl nitrate abuse, and cone or cone-rod degeneration syndromes.