Many of the eye tests we perform seem odd to people, especially during your first few visits with an optometrist. Here is an explanation of some of the regular eye tests we administer.
Be sure to mention if you experience headaches, eye fatigue, double vision, tunnel vision, dry eyes, sensitivity to light or other problems.
To measure how clearly you see at a distance, you will be asked to identify letters of various sizes, typically positioned 20 feet away.
This test helps our doctors determine the right prescription for your glasses or contact lenses. You look into a mask-like device called a phoropter, which holds lenses of various strengths. As you focus on an eye chart, your doctor will flip two lenses into your view and ask if the letters are more or less clear. This allows your doctor to pinpoint the power that gives you the best possible vision.
Your doctor will shine a light into each pupil to see whether both pupils are the same size and contract normally. Pupil problems can be a warning sign of high blood pressure, multiple sclerosis, glaucoma or neurological issues.
As your eyes move up and down, the doctor checks whether your eyes are properly aligned. This test screens for a disorder in which eyes do not move together when focusing on an object.
There are several ways to test your peripheral vision, but they all involve covering one eye and staring straight ahead with the other. You may watch a screen as dots of light flash and you will press a button each time you see a dot, enabling a computer to map your field of vision. The test detects blind spots due to glaucoma, a stroke or other ailments.
A slit lamp is a microscope with a thin beam of light, used to examine the front of each eye under magnification, including your iris (colored portion), sclera (white area), eyelids, lens, and cornea. The test checks for cataracts, macular degeneration, diabetic complications, corneal scratches or infections and chronic dry eye.
This test looks at the smoothness of your cornea. Your doctor places a drop of orange dye on the surface of your eye and will then look at your eye with a microscope that emits blue light. This test can be given to someone who’s had an abrasion, an infection, dry eyes or blurred vision.
This test, also known as tonometry, gauges the pressure inside your eyes, which goes up if you have glaucoma. The doctor uses special drops to numb your eyes. Then, using a little probe on the slit lamp, the doctor gently presses on each cornea to measure eye pressure. It doesn’t hurt, and the drops wear off in about 20 minutes. (This is the test that used to be the “air puff” test.)
To better understand vision problems, eye diseases, and eye exams, it can be helpful to get an anatomy refresher. Here’s a quick overview of the different parts of the eyes: