Evaluation of scleral canal diameters at optic nerve head in patients with nonarteritic anterior ischemic optic neuropathy using optical coherence tomography

To evaluate the clera canal diameters at optic nerve head in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography (OCT) and compare the results with fellow eyes and control group. In a prospective study, optic nerve head OCT was performed in acute phase of NAION. Horizontal and vertical diameters of the scleral canal at optic disc i.e. the termination of the retinal pigment epithelium, were recorded. The data was compared with fellow eyes and an age- and sex-matched normal control group. Thirty eyes of 30 patients and 20 eyes of 20 normal subjects were studied. Scleral canal diameters were the same for normal fellow eyes, optic atrophy fellow eyes and control eyes. Scleral canal diameters of NAION eyes were significantly greater than control and normal fellow eyes (P<0.001), however, the difference was not significant for optic atrophy fellow eyes. Although in the acute phase, the scleral canal diameters were greater in NAION eyes, no significant difference was found between normal fellow eyes and control eyes.