An eye exam isn't painful, but it can be intimidating, so the person you're caring for might appreciate your company and support. If he's becoming forgetful or fearful, he may be comforted by a brief explanation of what to expect, even if he's had many eye exams before.
During the exam, the doctor may:
- Ask about his health and any signs or symptoms of problems.
- Look at the outside of his eyes.
- Test how well he can see, using an eye chart of letters (called a Snellen chart) that get smaller as he moves down the chart. The doctor will ask him to read the chart -- which is usually placed 20 feet away -- out loud, first using one eye and then the other.
- Do a refraction assessment. This test examines how light waves are bent as they pass through the cornea and lens. Refractive problems can cause nearsightedness, farsightedness, astigmatism, and presbyopia. Some doctors use a computer to measure the angles, while others shine a light into the eye and take a measurement. Afterward, the doctor will ask a patient to look through a device while she flips through various lenses in front of his eyes, asking him to rate how he sees through them. When she does this, she's trying to find the best possible lens for his glasses. (If he has trouble telling which lens works better for him, that's fine -- he can just say so.)
- Test for peripheral (side) vision. There are several ways to do this. The doctor may use a computer that flashes lights to the right and left, or she may have him sit in front of a screen and stare at its center. In either case, the patient will be asked to say when he sees objects in his peripheral vision. Or the doctor may simply sit in front of him and cover one of his eyes while moving his hand in and out of his visual field. Looking at the doctor, he indicates when he can and can't see the moving hand.
- Test for color blindness, using pictures of multicolored dots that form numbers.
- Have him move his eyes in specific directions to evaluate his eye muscles.
- Examine the health of his eyes with a slit lamp. This magnifying machine gives the doctor a good look at the many parts of the eye, including the cornea, iris, retina, optic nerve, and macula. She may put an orange dye in his eyes during this part of the exam; this dye enables her to more easily detect tiny tears or scratches, infections, or foreign objects. Tears eventually wash the dye away.
- Examine the back of his eyes. To do this, the doctor may dilate them using eyedrops; this makes the pupils bigger to allow her a better look. She'll shine a light through the pupil to the back of the eye or use a bright light mounted on her forehead. She may also use the slit lamp to see more details. The patient may see afterimages when this exam is over, but that's perfectly normal. It's also normal for his vision to be blurry for several hours after his eyes are dilated.
- Test for glaucoma. To do this, the doctor needs to measure the pressure inside of his eye, using one of several methods, called tonometry. The most common is to use a puff of air to see how light reflections change as air hits the eye. For more about each method of testing for glaucoma, visit the National Library of Medicine.
- Give other tests as needed, depending upon the person's medical and eye history.
