Angle-closure, pupil dilatation, and pupil block

Abstract

Pupil-dilating eye-drops fall into two main groups-the tropine-like and the adrenaline-like drugs. For eyes with shallow anterior chambers and narrow angles there are different conditions for preferring one group or the other. In the presence of intact irides, the mild tropine-like drugs are best for dilating pupils. Although pupil-dilatation glaucoma is more likelywith thetropine group, the risk of pupil-block is less than with the adrenaline group. Further, the effects of the less potent tropine drugs (''Tropicamide'') are more readily reversed by miotics, than the effects of the adrenaline group. After peripheral iridectomy the risk of pupil-block is removed, and drugs of the adrenaline group (10 per cent. phenylephrine) are preferred because they will not close narrow angles, whereas the tropine group will close some angles despite open peripheral iridectomies. Following exterior filtering operations, a strong tropine drug (atropine) is necessary in the presence of flat anterior chambers. Explanations are given for these different effects.