Effect of Phenytoin on the Ganglion Cell Layer in Patients With Optic Neuritis

Optic neuritis typically occurs in young (mean age, 32 years), female (77%) patients, and it presents as subacute monocular visual loss that develops over several days. As yet, treatment with intravenous corticosteroid for optic neuritis had no long-term beneficial effect on vision. There are a number of factors that contribute to nerve fibre damage including increased level of sodium, so blocking sodium entry could help to protect them against damage. The main objective of the study is determine whether phenytoin (which blocks sodium entry) can protect nerve fibre and improve final visual function after optic neuritis.