Anti-epileptic drug protects eyesight of MS patients
Researchers have found that people with multiple sclerosis can be protected from the effects of an associated eye condition, acute optic neuritis, with a drug commonly taken to prevent seizures in people with epilepsy.
Acute optic neuritis is an inflammation of the nerve that carries visual information from the eye to the brain. Half of people with multiple sclerosis (MS) experience this condition at some point in their lives. It causes sudden total or partial blindness, foggy or blackened vision and pain. Each attack still damages the nerve and the eye, though eyesight can recover eventually. It is treated with steroid medications to hasten vision recovery. However, these do not improve its final extent. Thus there is a need for therapy to prevent further disability caused by MS relapses.
The study was centred on phenytoin, an anticonvulsant, or antiepileptic, drug that is used to control seizures by slowing down impulses in the brain that are responsible for them. A group of 86 participants with acute optic neuritis were randomly prescribed either phenytoin (4 mg/kg/day) or a placebo within 2 weeks of having symptoms, for a period of 3 months.
Using optical coherence tomography, the researchers measured the thickness of the retina both at the beginning of the study and 6 months afterward. In addition, they also assessed the participants’ eyesight, including color perception and sharpness.
The findings revealed that 30% less damage to retinal nerve fiber was experienced by those who received phenytoin. They also had 34% more volume of the macula, the most light-sensitive part of the retina. As expected, all the participants’ vision returned to normal after the episodes of acute optic neuritis had resolved. No significant differences in long-term visual outcomes between the group that received phenytoin and the control group were observed.
With the further research and larger studies to confirm the findings, a treatment to prevent nerve damage and blindness in MS could be developed. It could help other attacks of MS as well. These findings may set in motion studies that could have real positive implications for people with this debilitating inflammatory disease.
