Pupil dilatation with tropicamide. The effects on acuity, accommodation and refraction.

The effect of pupil dilatation with tropicamide 1% on visual acuity and accommodation was assessed in 100 eyes of 52 consecutive patients attending the general ophthalmic outpatient clinic. Snellen visual acuity remained unchanged in 55 eyes and deteriorated by one line in 41 eyes. The remaining four eyes deteriorated by two lines. Tropicamide gave rise to a reduction in the amplitude of accommodation which tended to vary inversely with the age of the patient. However, all patients who wore reading glasses for presbyopia were still able to read when their pupils had been dilated.