The Cleveland Clinic

Eye Tests and Exams

Here's a brief guide to the special eye tests your eye doctor may perform during an eye exam. In addition to a complete examination of your eye, your doctor may want to order one of the following eye tests.

Applanation Method

This eye test helps doctors diagnose glaucoma by measuring the amount of pressure needed to flatten a portion of the cornea. This is done by taking a thin strip of paper stained with the dye flourescein. This dye stains the front of the eye and enables a better eye exam by the doctor. The patient is then given a local anesthesia in the form of drops and the pressure is measured using a tonometer.

Corneal Topography

During this eye test, a computer is used create a "map" of the curvature of the cornea. The computer analysis will show any distortions of the cornea such as scarring, as well as conditions such as astigmatism . This eye test is used to screen patients before they undergo any refractive surgery , as well as for fitting contact lenses and corneal transplants.

This is an eye test used to evaluate the blood circulation in the retina. It is useful in helping diagnose diabetic retinopathy and retinal detachment . During this eye test, a special dye, called fluorescein, is injected into a vein in the arm. The dye quickly travels to the blood vessels inside the eye. Once it reaches the eye, a specialized camera equipped is used to photograph the fluorescein as it circulates though the blood vessels in the back of the eye. This will enable the doctor to diagnose any circulation problems, swelling, leaking or abnormal blood vessels.