Dr. Grossman’s Blog

Patients with the neurodegenerative disease referred to as Parkinson’s are often proscribed the drug amantadine to alleviate motor problems.    Amantadine treatment causes abnormal changes in the cornea in some Parkinson’s patients. Generally, these corneal reactions occur soon after starting the drug and disappear a few weeks after they stop taking. Occasionally, these issues arise after patients have been taking the drug for many years, and, in these cases, patients often do not recover even when amantadine is stopped.

A new study has been aimed at discovering  whether the effect of amandatine on corneal endothelial cells is dependent on the cumulative dose received. In a comparison study researchers found that patients with the highest cumulative amandatine intake and/or longest duration of treatment (up to 8 years) had the most significant reductions in endothelial cell density (ECD). Endothelial cells work to keep excess water out of the main body of the cornea. When there are too few endothelial cells, corneal edema (swelling) results and vision is impaired.

Study leader, Dr. Won Ryang Wee says: “Assuming other studies confirm these results, ophthalmologists and neurologists should consider evaluating a patient’s corneal endothelium at the beginning of treatment with amandatine and reassess at regular intervals if the drug is used long term, and additional monitoring would be needed for patients with other conditions that reduce ECD–such as recent cataract surgery or ongoing glaucoma, uveitis or Fuch’s dystrophy–because corneal edema could develop during treatment.”

Source: http://www.elements4health.com/long-term-parkinsons-drug-treatment-could-cause-vision-impairment.html