April 4, 2012

Why Dilate?

By James Wymore, M.D.
Eye Surgeons Associates

A trip to the eye doctor. It’s not always a favorite activity, and on top of that, one sometimes has to endure the annoyance of dilation. It lengthens the time in the doctor’s office, it makes the eyes sensitive to light, and it may blur at least the reading vision. Can’t the eye doctor examine your eyes and test for glasses without dilation? The answer is not completely.

There are visits that don’t necessitate dilation. Evaluation and treatment for eye infections like conjunctivitis, a follow-up intraocular pressure check for glaucoma, removing foreign bodies from the eye, and treating ocular allergies are some of the occasions that a patient escapes the clutches of dilation. These involve examination of the external portions of the eye, and drops are not needed to open the pupil further.

The most common indication for dilation is during the complete examination, either for a new patient or for regular eye checks (intervals for which are determined by age, race, family history, and presence of eye disease). By widening the pupil with dilation, the internal ocular structures, including lens, vitreous, retina, choroid, and optic nerve, are more easily scrutinized for ocular disease, symptomatic or not. The true refractive error (need for glasses) can be determined as well. The accommodative (focusing) ability of the human lens can mask the presence of significant farsightedness, or cause nearsightedness to be overestimated. Dilation can help paralyze accommodation, uncovering these problems.

Dilation allows almost the entire lens to be viewed. Presence and extent of cataracts can then be documented. Pseudoexfoliation, a “dandruff-like” appearance on the lens surface, which is associated with glaucoma, is another example of lens pathology more easily discovered with dilated pupils.

The central and back portions of the eye require dilation to be fully seen. Retinal tears and detachments fall into this category, occurring many times in the retinal periphery. Indirect ophthalmoscopy, or other means of observing the peripheral retina, is essential when a patient experiences flashes and floaters. One of the important facets of following glaucoma, evaluation of the optic nerve, is much more easily accomplished with dilation. Macular degeneration and diabetic retinopathy are other common retinal problems. A larger pupil facilitates the search for complications that can be corrected by medication or laser treatment.

Dilation, along with cycloplegia (paralyzing accommodation), can also be therapeutic. The pain of corneal abrasions or inflammation will be relieved with cycloplegic drops. Inflammation intraocularly (iritis or uveitis) is benefited in two ways. Pain is decreased, and scarring of the iris to the eye lens is avoided.

Dilation has its purposes. In spite of the temporary discomforts, it is indispensable for diagnosis and treatment of various ocular conditions, helping us to prevent vision loss.

Dr. Wymore, with Eye Surgeons Associates, is a board-certified general ophthalmologist. He is a member of the American Academy of Ophthalmology. Dr. Wymore practices at our offices in Bettendorf, Iowa and Rock Island and Silvis, Illinois. For more information, please see our website: www.esaeyecare.com.