OCULAR HEMODYNAMIC-EFFECTS OF ACUTE ETHANOL INGESTION

Purpose: Because the protean biological effects of ethanol include acu te alterations in both cortical function and circulatory control, we i nvestigated the effect of acute alcohol consumption on retrobulbar hem odynamics and contrast sensitivity in healthy human volunteers. Subjec ts and Methods: Twelve young adults received orange juice with and wit hout ethanol in a double-masked fashion. The ethanol dose was sufficie nt to raise blood alcohol to 0.07 +/- 0.003 g/dl. Retrobulbar hemodyna mics were assessed at baseline and twice at elevated blood alcohol by color Doppler imaging. Results: Acute elevation of blood alcohol lower ed intraocular pressure from 13.0 +/- 0.7 to 10.7 +/- 0.7 mm Hg (p < 0 .05). In contrast, elevated blood alcohol left peak systolic velocity, end-diastolic velocity and the resistance index constant in three ret robulbar arteries (ophthalmic, central retinal and posterior ciliary). For example, in the central retinal artery, peak systolic velocity, e nd-diastolic velocity and the resistance index averaged 11.0 +/- 1.3 c m/s, 2.8 +/- 0.4 cm/s and 0.75 +/- 0.03 before ethanol, as compared wi th 10.5 +/- 1.0 cm/s, 2.9 +/- 0.3 cm/s and 0.72 +/- 0.03 after ethanol (all p = NS). Alcohol ingestion also failed to alter either visual ac uity or contrast sensitivity, as assessed under both photopic and meso pic conditions. Conclusions: Although ethanol has widespread cognitive and cardiovascular effects, at blood levels near legal definitions of intoxication we found it ineffective in altering either retrobulbar h emodynamics or contrast sensitivity.