What Are Eye Exams?
An eye exam is a checkup from a health care professional that looks at your vision and eye health. You should have regular eye exams even if you don't wear contacts or glasses. If you have certain medical conditions, such as diabetes, you may need to have your eyes checked more often.
Why Do You Need Eye Exams?
Many eye conditions don't have symptoms in their early stages. The best way to catch these problems is with an eye exam. If you get an early diagnosis and begin treatment, you'll probably have a better outcome.
With some conditions, early detection and treatment can prevent you from losing your eyesight altogether.
Vision problems can affect your life in many ways. Studies have shown that eye conditions can affect your mental health and keep you from engaging with your community. If your vision is poor, you're more likely to fall or have trouble getting around. When you have vision problems, your chances of having a car accident while driving increase.
Researchers have found that correcting vision problems can make people more productive at work and improve their overall quality of life.
A comprehensive eye exam includes several elements.
Visual Acuity Test
This measures how well you see at near and far distances.
The most common way to do this is using what's called a Snellen chart. The chart has larger letters or symbols at the top, and they get smaller as you move down the rows. When you think of having your eyes checked, the eye chart test may be the first thing that comes to mind.
What if your child isn't old enough to read and can't recognize letters? Doctors have special tests for children, including one using what's called LEA symbols. These are common objects your child should recognize, such as an apple, house, or circle.
The results of this test are written as a fraction, such as 20/20 -- the number for normal visual acuity. The top number represents 20 feet -- that's the standard distance in testing. The bottom number represents the smallest letter size you were able to read. If you have 20/40 eyesight, for instance, you have to get within 20 feet to be able to read a letter than someone with normal eyesight could see at 40 feet.
Visual Field Test
This exam checks your vision in various spots -- straight ahead and to the sides (peripheral vision). If you have blind spots or gaps in your vision, this test will help find them.
You’ll stare at an object in the center of your line of vision (like the doctor's eyes or a computer screen). As you look at the target, you’ll note when you see an object moving into your field of vision or, depending on the test, when the lighted spot appears. This test lets the doctor know if conditions like stroke or glaucoma have hurt your vision.
Refraction Test
This exam helps your health care professional determine your eyeglasses prescription. Problems such as nearsightedness, farsightedness, and astigmatism are called refraction errors. The lenses in your glasses correct these issues.
You'll look at a chart, usually 20 feet away, or in a mirror that makes things look like they’re 20 feet away, using a tool called a phoropter. Your health care provider will move lenses of different strengths in front of your eyes. You can tell them if things look clear or blurry. Your answers give them your prescription for your glasses or contact lenses.
Dilated Pupillary Exam
The doctor uses special drops to expand your pupils. They’ll call this dilation.
You'll need a dilated pupil exam every one to two years if you:
- Are older than 60
- Are an African-American person and older than 40
- Have a family history of glaucoma
Dilating your eyes allows more light in, which makes it easier for your health care provider to spot problems. Using an instrument called a ophthalmoscope, the doctor will look at the structures at the back of your eyes. This area includes your retina, nearby blood vessels, and optic nerve. It's called the fundus.
Among the conditions your doctor might find during a dilated pupil exam are:
- Diabetic retinopathy
- Glaucoma
- Age-related macular degeneration (AMD)
Slit-Lamp Exam
A slit lamp is a type of microscope. It has a very strong light that can be concentrated into a thin line.
For the test, you'll sit in a chair and rest your chin and forehead against supports on the machine. This keeps your head steady.
The bright light and microscope let your health care provider check your eyelids, cornea, conjunctiva, sclera, and iris. To check the cornea, they might use yellow dye (fluorescein). You might get the dye in an eye drop, or the doctor might touch a small strip of paper to your eye. When you blink, your tears will rinse the dye out.
Among the conditions this exam might find are:
- Cloudy lens (cataract)
- Cornea injuries
- Macular degeneration
- Detached retina
- Dry eye syndrome
- A degeneration of your retina caused by your genes (retinitis pigmentosa)
- Swelling or irritation of the middle area of your eye (uveitis)
Ophthalmoscopy
The slit-lamp test is one type of ophthalmoscopy. Other types are:
Direct ophthalmoscopy. You'll sit in a dark room while the doctor shines a ophthalmoscope at your eyes. The device has different lenses to make measurements.
Indirect ophthalmoscopy. For this test, your chair might be tipped back, or you might lie down. The doctor wears a device that looks like a headlamp. They'll hold your eye open while they check the back of your eye. The might apply pressure to your eye using a small probe. This test is often used to check for a detached retina.
Other reasons you might have your eyes checked with an ophthalmoscope include:
- Glaucoma
- High blood pressure
- Diabetes
Non-Contact Tonometry
You might hear this called an "'air-puff" test. It measures the pressure inside your eye, which is known as intraocular eye pressure (IOP).
The doctor uses a device to blow a small puff of air at your eye. Higher than normal pressure in your eye can be a sign of glaucoma.
When you have glaucoma, the increased pressure in your eyes damages your optic nerves. This can lead to blindness.
Applanation Tonometry
This is another way to measure your intraocular pressure (IOP).
The doctor touches a small instrument, called a tonometer, to your eye. You might receive numbing eye drops first, so that you don't feel the device against your eye.
Retinal Tomography
This computerized test can give a remarkably detailed image of the retina and all of its layers.
You'll probably receive numbing eye drops before the test.
For the test, you'll sit in a chair and rest your chin on a bar and your forehead against the machine. Your health care provider will make sure the camera is in the right spot, then start taking images of your eye. They'll photograph one eye at a time. You might have to concentrate on a green light, which can cause mild discomfort.
The test takes 5 to 10 minutes.
Among the problems this exam can detect are:
- Macular edema caused by diabetes
- Damage to your retina caused by diabetes
- Cancer
- Glaucoma
- Detached retina
- Problems with your retinal vein
- Damage to your macula
Ultrasound
This type of test uses sound waves to map the structure of the eye. The sound waves travel through your eye, and the echoes form a picture.
You'll get numbing eye drops before the exam, and the ultrasound wand is placed against your eye. Most people have this test sitting up, with their chin and forehead resting on a support. But it's sometimes done with the patient lying down.
Doctors use this test before cataract surgery to determine the right strength of a lens implant. They also can use this test to check for problems with your retina or to see tumors.
Corneal Topography
This computerized test maps the curve of your cornea. It can show problems with your eye’s surface, such as swelling or scarring, or conditions such as astigmatism or diseases like keratoconus. You might have it before you have surgery, a cornea transplant, or a contact lens fitting.
For the exam, you'll be seated in front of a device that looks like a bowl with lighted circles inside. You'll rest your chin and forehead against the supports. You concentrate on a fixed spot in the bowl while the images are taken. The test takes only a few seconds, though you might have to repeat it to get the best images.
Nothing touches your eyes during the exam, so you won't feel anything.
Fluorescein Angiogram
This lets the doctor see how well blood moves in your retina. It helps diagnose diabetic retinopathy, retina detachment, and macular degeneration.
First, you'll get eye drops to dilate your pupils. Then you'll have a special dye, called fluorescein, injected into a vein in your arm. The dye travels quickly through your body, and in 20 seconds or so, it will reach the blood vessels in your eye. They will fluoresce, or light up, for a special camera.
The camera takes pictures of the dye as it goes through the blood vessels in the back of your eye. This helps doctors spot circulation problems, swelling, leaking, or abnormal blood vessels.
How Often Should You Get Eye Exams?
Experts recommend you follow this schedule for eye exams, unless you have a condition that puts your eye health at risk:
| Age | Frequency |
| Birth through age 2 | Exam at 6-12 months |
| Ages 3-5 | At least one exam during this period |
| Ages 6-17 | Exam before entering first grade, annually as needed |
| Ages 18-39 | Exam at least every 2 years |
| Ages 40-64 | Exam at least every 2 years |
| Age 65 or older | Every year |
Conditions that might prompt children to be tested more often include:
- Low birth weight, premature delivery, or supplemental oxygen after birth
- Family history of eye problems
- Infection during delivery
- Strabismus (crossed eyes)
- Academic problems
- Neurodevelopmental disorders
- Eye surgery or eye injury
- Taking medicine known to affect the eyes
Conditions that might prompt adults to be tested more often include:
- Family history of eye disease
- Work that is known to strain the eyes or be dangerous to vision
- Taking medicine known to affect the eyes
- Eye injury or surgery in the past (including LASIK, PRK, or SMILE)
Takeaways
Comprehensive eye exams are a way to monitor your eye health. Regular eye tests are important because vision is key to how you function in the world. During an eye test, your health care provider will check how well you can see (acuity) and whether you have gaps or blind spots in your vision. They'll also check the pressure in your eyes and use devices that help them see the structures of your eye better, including your retina, optic nerves, and blood vessels. These tests will help spot potential problems such as glaucoma, cataracts, and macular degeneration. Early diagnosis and treatment can protect you against vision loss.
Eye Exams FAQs
How often should I get an eye exam?
This depends on many factors, including whether you already wear glasses, how old you are, and whether you have a condition that affects your vision. If you have no problems and are younger than 65, you should probably have your eyes checked every one to two years.
What happens during a comprehensive eye exam?
Your health care provider will check how well you can see. If your eyesight needs correction, they'll use a tool to determine what strength lenses you need. They'll also check for signs of glaucoma, cataract, and macular degeneration. This includes using a bright light to look at the structure of your eyes and testing your intraocular pressure.
Why are eye tests important for overall health?
Studies have linked vision problems to poorer quality of life. If you have a vision problem, you may be more likely to fall, have trouble getting around, or be involved in a car accident. Your eye health also can have an impact on your mental health.
