Dilated Eye Exam

The full retinal view through widened pupils

Overview

A dilated eye examination is an eye examination performed after eye drops have widened the pupils, allowing a much more complete view of the lens, vitreous, retina, and optic nerve than is possible through an undilated pupil. Commonly used drops include tropicamide, which blocks the muscle that constricts the pupil, and phenylephrine, which stimulates the muscle that dilates it. Once the pupils are dilated, the examiner uses a slit lamp with handheld lenses and an indirect ophthalmoscope to inspect the retina out to its periphery. Dilated examination can reveal diabetic retinopathy, macular degeneration, retinal tears and detachments, optic nerve disease, tumors, and signs of systemic conditions such as hypertension. Dilation temporarily causes light sensitivity and blurred near vision for several hours. Ultra widefield retinal imaging can capture much of the retina with or without dilation and is used in screening, but dilated examination remains a standard part of comprehensive eye care. Rarely, dilation can precipitate acute angle closure in eyes with narrow drainage angles.