Peripapillary Capillary Network in Methanol Induced Optic Neuropathy

To present the optical coherence tomography angiography (OCTA) findings of the radial peripapillary capillary (RPC) network in an individual with severe bilateral methanol-induced toxic optic neuropathy (MTON) in comparison to a normal subject and a patient with retinitis pigmentosa.

A 35-year-old man with severe bilateral MTON was referred to the neuro-ophthalmology clinic at the Labbafinejad Medical Center. The Angio Vue OCT 3D set of 4.5 × 4.5 mm was used to measure the disc and peripapillary vessel density. Two subjects were examined with the same protocol as controls to determine the effect on the RPC vessel density in multiple scenarios. One of the controls was a healthy individual with the prerequisite matches of age and sex while the second one was a known retinitis pigmentosa (RP) patient. RPC density was measured as 37.7 in the patient with MTON, 46.9 in the RP patient, and 54.7 in the healthy control.

The reduction in the RPC vessel density in a patient with MTON compared to that of a healthy individual and also a patient with RP may be due to the loss of capillaries secondary to the loss of nerve fibers and ganglion cells. Moreover, MTON can be considered an optic neuropathy with direct mitochondrial damage to the endothelial cells of the capillaries.