The effect of amantadine on corneal endothelium in subjects with Parkinson's disease.

OBJECTIVE

To evaluate the effect of amantadine on corneal endothelial cells in subjects with Parkinson's disease.

DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 169 subjects (169 eyes) taking amantadine orally for Parkinson's disease and the same number of age- and gender-matched controls.

METHODS

Endothelial indices were compared between the amantadine-treated and age-matched control groups. The amantadine-treated group was divided into 3 subgroups according to the cumulative dose and duration of treatment. Endothelial changes were compared between the amantadine group and the normal control group, and among subgroups.

MAIN OUTCOME MEASURES

Slit-lamp biomicroscopy, central corneal thickness (CCT), endothelial cell density (ECD), coefficient of variation, and hexagonality.

RESULTS

The amantadine group had significantly lower ECD (mean +/- standard error; 2662.47+/-29.06 vs. 2784.72+/-25.89, P = 0.002), lower hexagonality (56.94+/-1.07 vs. 60.97+/-0.87, P = 0.004), and greater coefficient of variation (35.59+/-0.57 vs. 32.66+/-0.52, P = 0.000) compared with the age-matched control group. Longer duration and higher cumulative dose amantadine therapy led to a greater reduction in ECD (P<0.05) compared with the normal age-matched control group.

CONCLUSIONS

Amantadine is more likely to have an effect on corneal endothelial cells in a dose-dependent manner when used long-term.