The Effects of a Single Intramuscular Injection of Atropine Sulphate on Visual Performance in Man

Abstract

The effects of a single intramuscular injection of 2 mg atropine sulphate on visual function were studied in volunteer subjects. The well-known effects of increased heart rate, dryness of the mouth, ncreased pupil diameter and reduced accommodative range were confirmed. Visual acuity, stereoacuity, red-green colour balance and reaction time to a visual stimulus were unaffected by atropine, while extraocular muscle balance (horizontal heterophoria and cyclophoria) underwent a transient change. There was no significant change in contrast sensitivity measurements to stationary sinusoidal grating patterns of spatial frequencies 1-30 c/deg; however contrast sensitivity o moving grating patterns of spatial frequencies 1-5 c/deg showed a sustained reduction which was ,till present at 6 h post-injection. It is concluded that atropine adversely affects movement letection but not stationary visual function.