The effect of phenylephrine on the accommodative process in man.

Accommodation was measured in a double-blind study on 10 healthy volunteers (22-29 years) before and after the instillation of 0.1%, 1.0% and 10% phenylephrine eye drops. Accommodation decreased exponentially with increasing concentration, reaching an average of 3 dioptres after one drop of 10% phenylephrine. The effect of adding phenylephrine to an atropinized eye was studied in 20 children (3-6 years). The children were randomized to placebo or phenylephrine treatment. The cycloplegic effect of atropine was unchanged in 8 out of 9 placebo-treated children, whereas 5 out of 11 phenylephrine-treated children showed a slight, but not significant, increase in hypermetropia.