Effects of routine pupillary dilation on functional daylight vision.

The visual acuity of 100 patients between the ages of 16 and 66 years, seen for routine ophthalmologic examination, was measured before and after dilation. All patients had a predilation visual acuity of 20/40 or better. Postdilation binocular visual acuity using the patients' usual correction was measured first in the office and then outdoors, both with the patient's back to and the patient facing the sun, with and without the aid of postmydriatic sunglasses. Twelve percent experienced disabling photophobia even with the use of postmydriatic sunglasses, with 3% having significant objective visual loss defined as 20/50 or worse. No objective visual loss was found in 30 controls examined outdoors before dilation, without sunglasses. We recommend that patients who have experienced significant photophobia with dilation in the past, or who have never before undergone dilation, make arrangements for transportation after a dilated examination.