Assessment of tear amount in subjects under the effect of (inhaled) cocaine.

The topic of ophthalmic use of cocaine in clinical practice has a long history; nevertheless, the possible influence and pathways of action of inhaled cocaine in the human eye remain unknown. This study evaluates the effect of snorted cocaine in the eye tear of 22 occasional cocaine users using the Schirmer Test I (ST1). The tear amount without the subjects being under the effect of cocaine was (mean +/- standard deviation) 22.50 +/- 12.85 mm ranging from 5-55 mm. Under the effect of cocaine, 17 in 22 eyes had a decrease in the tear amount, averaging 16.52 +/- 10.13 mm ranging from 1-38 mm, representing a statistical significant decrease (paired t-test, one-tailed p = 0.0024) of about 27% between the previous conditions. The large majority of the subjects under the effect of cocaine present a decrease in ST1 determining a global statistical significant decrease in ST1. That suggests a relationship between snorted cocaine and a reduction in tear amount. The identification of the tear cocaine effect and the pathway of action cannot be overlooked in the research for a comprehensive characterization of inhaled cocaine action in the central and peripheral nervous system.