Eye Examinations: What to Expect
An Overview of an Eye Exam
During an eye appointment several types of eye tests may be performed. In addition to a complete eye examination, your doctor may want to order one of the following special tests:
- Applanation tonometry: A test that helps doctors diagnose glaucoma by measuring the amount of pressure needed to flatten a portion of the cornea.
- Corneal topography: During this procedure, a computer is used to create a "map" of the curvature of the cornea. The computer analysis will show any distortions of the cornea (e.g., scarring) as well as conditions such as astigmatism.
- Fluorescein angiography: This is a test used to evaluate the blood circulation in the retina. It is useful in helping to diagnose diabetic retinopathy and retinal detachment.
- Pupillary dilation test: During this procedure, the eye doctor places special drops in the eye, causing the pupil to dilate (expand). By dilating the pupils, your doctor can examine your retina for any signs of disease.
- Refraction test: This test measures your ability to see objects at specific distances. It is often done by having the patient look at a chart at a fixed distance, usually 20 feet away.
- Slit-lamp exam: A test that looks at the front of the eye by shining a beam of light shaped like a small slit on the eye. The test can be used to help diagnose cataracts, retinal detachment, macular degeneration, injuries to the cornea and presbyopia.
- Tonometry: This is a procedure used to help diagnose glaucoma. In tonometry, a small, smooth instrument known as a tonometer is lowered onto the surface of the eye in order to measure the pressure in the eye.
- Ultrasound: An ultrasound uses sound waves to provide a picture of the eye’s internal structure. It is useful in evaluating ocular tumors and in evaluating the retina when it is being obscured by cataracts or a hemorrhage.
- Visual acuity testing: A test of your visual acuity, or ability to see sharply and clearly at near and far distances will be performed.
- Visual field test: A test used to measure peripheral (side) vision. When given this test, you will be asked to stare at an object in the center of your line of vision (either the doctor’s eyes, on a screen or using a computer program).