Retinal inner nuclear layer microcystic changes in optic nerve atrophy: a novel spectral-domain OCT finding

Optic atrophy constitutes the final stage in the evolution of optic neuropathy. The aim of this study was to describe the presence of macular microcystic changes or pseudocysts in patients with advanced optic atrophy.

The medical records of 24 patients who had retinal pseudocysts in association with optic atrophy have been analyzed. All patients underwent a complete neuro-ophthalmologic assessment; peripapillary retinal nerve fiber layer thickness and macular screening with spectral-domain optical coherence tomography and optical coherence tomography "en face" imaging analysis were also performed.

A total of 36 eyes were included in the study. Patients' mean age was 37 years. The major cause of optic atrophy was glaucoma (12 cases). The retinal pseudocysts were observed as hyporeflective lesions in the internal nuclear layer. Infrared images revealed a hyporeflective circular or semilunar shape corresponding to the location of the pseudocysts in all cases. In eyes with pseudocysts, mean thickness of the peripapillary retinal nerve fiber layer was statistically significantly less than that of fellow eyes (P = 0.0003), whereas macular thickness was statistically significantly higher compared with fellow eyes (P < 0.005).

The presence of pseudocystic lesions always associated with severe optic nerve fiber loss is reported. The reason why pseudocystic lesions develop within the retina is not well understood. They might constitute the translation of degeneration of Muller cells in severe optic nerve fiber loss. Recognizing these pseudocysts is crucial because they may be confused with cystoid macular edema. Their prognostic value and role in the therapeutic process need to be further evaluated with prospective studies and molecular experiments in vivo.