Spectral-domain optical coherence tomography reveals prelaminar membranes in optic nerve head pallor in eyes with retinitis pigmentosa

Purpose: To determine the relationship between prelaminar structural changes of the optic nerve head (ONH) and optic nerve waxy pallor in retinitis pigmentosa (RP) using spectral-domain optical coherence tomography (SD-OCT) and fundus photography. Methods: An observational cross-sectional case control study of patients with RP with and without ONH waxy pallor and controls. Subjects underwent clinical examination, fundus photography, and SD-OCT raster imaging of the ONH. Four independent specialists reviewed the images in a masked fashion. Results: Fifty-five eyes of 31 subjects with RP and 28 eyes of 14 controls were included. Optic nerve head waxy pallor was seen in 29 RP eyes (52.7 %) and none in controls. SD-OCT showed a hyper-reflective structure suggestive of a glial membrane-like structure on the surface of ONH in 16 of RP eyes (55.1 %). In the RP group, there was a significant positive correlation between the ONH pallor and the presence of a prelaminar structure (p = 0.006). Conclusions: There is a presence of glial membrane-like structures on the optic nerve head surface in eyes with RP compared to healthy eyes. As the presence of glial membranes correlated with the presence of ONH waxy pallor, in such cases these membranes might be responsible for ONH waxy pallor.