The influence of a social dose of alcohol on the central visual field.

The influence of a socially acceptable dose of alcohol (mean blood alcohol level approximately 90 minutes after ingestion 69.5 mg%; SE 6.20 mg%) on the central visual field as determined by automated static perimetry was investigated in 17 female subjects (17 eyes) trained in automated perimetry (mean age 22.5 years, SE 1.29 years). Central visual field examination was undertaken on the right eye with program 30-2 (stimulus size III) of the Humphrey Field Analyser 630, using a simple cross-over placebo design. Alcohol produced a small (1.0 dB) but statistically significant decrease in the mean deviation (P = 0.002) and small increases (0.6 dB) in the pattern and corrected pattern standard deviations (P = 0.003 and P = 0.046, respectively). The number of stimulus presentations increased by 6% (P = 0.006) and the number of false-negative responses also increased (P = 0.019), indicating impaired patient response. Attenuation of sensitivity as a result of alcohol increased with the increase in eccentricity (P = 0.046) independently of the meridian (P = 0.068) from a mean of 0.8 dB at 3 degrees eccentricity to 1.84 dB at 27 degrees.