Epilepsy Drug Protects Eyesight of Multiple Sclerosis Patients

Phenytoin helps to reduce damage to the nerve fiber.

Phenytoin helps to reduce damage to the nerve fiber.

A drug that prevents seizures in epilepsy may be able to protect the eyesight of multiple sclerosis (MS) patients, a recent study found.

In a study presented this week at the American Academy of Neurology's annual meeting in Washington, DC, researchers examined methods to protect damage that occurs to the optic nerve as a result of MS.

"About half of people with MS experience at some point in their life a condition called acute optic neuritis, in which the nerve carrying vision from the eye to the brain gets inflamed," said study author Raj Kapoor, MD, in a press release. "The condition can cause sudden total or partial blindness, foggy or blackened vision and pain. Even though eyesight can recover eventually, each attack still damages the nerve and the eye."

The researchers randomly selected 86 people with acute optic neuritis within 2 weeks of reporting symptoms to receive either the epilepsy drug phenytoin or a placebo for a duration of 3 months.

Medical imaging was used to measure retina thickness at the start of the study and after 6 months of treatment. The researchers also tested eyesight, including sharpness and color perception.

The results showed that patients in the phenytoin group had 30% less damage to the nerve fiber layer compared with patients in the placebo group. The volume of the most light-sensitive part of the retina, called the macula, was found to be 34% higher in the phenytoin arm than in the placebo arm.

Following a single attack, the vision of patients recovered and there were no significant differences found in long term visual outcomes between both treatment groups.

"Eyesight is key to many important aspects of life, such as working, driving and participating in social activities," Dr. Kapoor said. "If this finding is confirmed by larger studies, it could lead to a treatment that may prevent nerve damage and blindness in MS, and could help other attacks of MS, serving a major unmet need."

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