Effects of dopamine antagonists in human eye accommodation

The purpose of this study was to evaluate the effects of dopamine antagonis ts in accommodation of the human eye. The dopamine antagonist drugs used in this experiment include 0.5% metoclopramide and 0.25% droperidol. Eighteen healthy subjects were enrolled; they were randomly assigned, in double-mas ked fashion, to receive topical administration of a single drop of either 0 .5% metoclopramide or 0.25% droperidol in one eye, with the fellow eye rece iving isotonic saline as control. The accommodative abilities of both eyes were measured before instillation, and also at 3 and 6 hr after instillatio n of drugs, respectively. We studied the latency of reaction, the rate of a ccommodation, the average accommodative power, the rate of recovering and t he total recovering time as the five parameters for evaluating the accommod ative ability of each eye. The results showed that there were significant changes in two parameters: t he rate of accommodation and rate of recovering, whereas there were no sign ificant changes in the other three parameters: latency of accommodation, av erage power of accommodation and total recovering time. In conclusion, the dopamine antagonists may have some effects on the rate of accommodation but not the degree of accommodation. Further studies with higher concentration s of these dopamine antagonists on dose-response relationships are needed b efore exact drug efficacy carl be drawn.