Neurological Testing A series of tests will be performed to determine how the nervous system (brain) works with the eyes. Tracking of the eyes into six different directions, peripheral vision, and pupil function are all part of a simple set of tests done during an eye exam. These tests help your Optometrist determine how well your eyes communicate with the brain. It can help check for a number of serious conditions such as brain tumor, aneurysm, concussion, and stroke.
Visual Acuity Test This test measures how clearly you can see from a distance and while reading. Your doctor will ask you to identify different letters of the alphabet printed on a chart (Snellen chart) positioned usually 20 feet away. The lines of type get smaller as you move down the chart. You cover one eye and read aloud, then cover the other eye and read aloud.
Refraction Assessment Refraction refers to how light waves are bent as they pass through your cornea and lens. A refraction assessment helps your doctor determine a corrective lens prescription that will give you the sharpest vision. Your doctor may start with a computerized refractor to measure your eyes and estimate the prescription you need to correct a refractive error. Or he or she may use a technique called retinoscopy. In this procedure, the doctor shines a light into your eye and measures the refractive error by evaluating the movement of the light reflected by your retina.
Your eye doctor fine-tunes this refraction assessment by having you look through a Phoroptor, a mask-like device that contains wheels of different lenses, to judge which combination gives you the sharpest vision. By repeating this step several times, your doctor finds the lenses that give you the greatest possible acuity.
Slit-lamp Examination A slit lamp is a microscope that enlarges and illuminates the front of your eye with an intense line of light. Your doctor uses this light to examine the cornea, iris, lens and anterior chamber of your eye.
When examining your cornea, your doctor may use eye drops containing fluorescein (flooh-RES-ene) dye. The orange dye spreads across your eyes to help your eye doctor detect tiny cuts, scrapes, tears, foreign objects or infections on your cornea. Your eyes' tears eventually wash the dye away.
Retinal Examination A retinal examination — sometimes called ophthalmoscopy or fundoscopy — examines the back of your eye, including your retina, optic disk and the underlying layer of blood vessels that nourish the retina. The retinal examination takes only a few minutes, but if you're given eyedrops to dilate the pupils, their effects may not wear off for several hours. Your vision will likely be blurry, and you may have trouble focusing your eyes. If you're particularly sensitive to light, you may need to wear dark glasses (or sunglasses) for a short time. You may not be able to drive, so make sure you have another way back to work or home. Depending on your job, you might not be able to work until the effects of the eyedrops wear off.
Tonometry The most common type of tonometry is the dreaded "air puff" test. This is a test that measures the pressure inside your eyes and is a screening test for glaucoma. It does not require the use of any eye drops in the eye, however, it can be startling to you — especially for first-timers. If you prefer, there are other methods for acquiring this measurement. Applanation tonometry is a less-startling method of measuring eye pressure, but does require a short-acting numbing drop in each eye. You can always request applanation tonometry, if you do not like the "air puff".
Besides these basic evaluations, you may need more specialized tests, depending on your age, medical history, family history, or if any of the tests above are abnormal.