Vision Screening

What is vision screening?

A vision screening (also called an eye test) checks how well you can see things up close and far away. It usually involves reading letters or identifying pictures or symbols on an eye chart.

A vision screening can also tell you if you need a comprehensive (complete) eye exam, which looks not only at how well you see but also at your overall eye health. This full exam looks for signs of serious eye disorders that may not have symptoms, such as glaucoma.

Children usually have vision screening tests as part of routine health checkups or at school. For infants and toddlers, health care providers use different screening tests to check the health of the child's eyes and whether the eye muscles are working correctly.

Adults may have their vision screened during routine health checkups. But usually, their vision is screened as part of a complete eye exam from an eye care specialist. The two main types of specialists are:

• Ophthalmologists, who are medical doctors able to diagnose and treat all types of vision and eye disorders.
• Optometrists, who are trained to diagnose and treat certain types of vision and eye disorders and prescribe eyeglasses or contact lenses.

While vision screening can identify some common vision problems, it may miss other types of eye disorders. Because of this, it's important for you or your child to get regular, comprehensive eye exams.

Other names: eye test, vision test

What is it used for?

For infants and children: Your child's provider will use special vision screening tests to look for signs of common eye conditions that need early treatment. These eye conditions include:

• Amblyopia (or "lazy eye"), which causes poor vision in one eye due to a problem with how the brain and eye work together. This is the most common cause of vision loss in children.
• Strabismus, which causes each eye to look in a different direction. One or both eyes may turn in ("cross-eyes") or turn out ("walleyes"). If strabismus isn't corrected, it can cause amblyopia and permanent eye damage.

For children starting at about age 3, screening for problems with near and far vision is used to help find common vision problems that can be corrected with eyeglasses or contact lenses. In certain cases, eye surgery may also be an option. These conditions include:

• Nearsightedness (myopia), a condition that makes far away things look blurry
• Farsightedness (hyperopia), a condition that makes close-up things look blurry
• Astigmatism, which causes generally blurry vision and makes it hard to see at night

For adults, vision screening can help to find any of the above vision problems. The results of a screening test can also lead to a referral to an eye care specialist who can identify vision changes related to aging, diabetes, or neurological conditions. This includes:

• Presbyopia, a condition that makes it hard to see things up close. It's a normal part of aging that makes the lens of the eye less flexible. This condition often begins around age 45.
• Glaucoma, a group of diseases that can damage the optic nerve of one, or both, of your eyes. This damage can lead to vision loss.
• Cataracts, which is a clouding of the lens in your eye. Cataracts affect your vision and are very common in older people.

Vision screening tests may also be used in specific settings, such as for driver's license exams.

Why do I need vision screening?

Babies and children need regular tests to check the health of their eyes. Once your child is over the age of three, they will usually start getting regular vision screening. This helps find and correct vision problems before they affect learning or cause permanent vision loss. Ask your child's provider how often your child should have vision screening tests. They may need them more often if they:

• Were born prematurely
• Have signs of eye disease
• Have a family history of childhood eye disease

In general:

• Newborns should be checked for eye infections and signs of other eye disorders.
• At 6 months to a year, eyes and vision should be checked during a regular well-baby visit. These tests are needed to check for early signs of strabismus.
• At 3 to 5 years, screening for near and far vision may begin for children who are able to describe what they see on an eye chart. This screening can be used with other tests to check for signs of amblyopia. All children should have at least one vision screening during this time.

If your child has symptoms of an eye disorder, a vision screening may help decide if an exam from an eye care specialist is needed.

For babies under a year old, symptoms include:

• After 3 months: Not being able to follow a moving toy or other object with their eyes.
• After 4 months: Eyes that don't look properly lined up. Before 4 months, it's normal if your baby's eyes briefly look in different directions from each other.

For older children, other symptoms of vision problems include:

• Squinting or frowning
• Closing or covering one eye
• Trouble reading and/or doing close-up work
• Complaining that things are blurry
• Blinking more than usual
• Crankiness when using close-up vision, such as looking at books
• One or both eyes that are watery, red, swollen, or crusted

For adults, vision screening helps to find out whether you need a complete eye exam from an eye care specialist. If you have vision screening as part of a complete eye exam, the test will show how well you're seeing at different distances, including with corrective lenses (eyeglasses or contact lenses). You may need this test if you notice any changes in your vision or if you start having difficulties reading or seeing things in the distance.

Adults may also need more frequent eye exams if they have a condition that often affects eye health. These conditions include:

• Diabetes
• High blood pressure
• Inflammatory conditions such as Crohn's disease, lupus, and multiple sclerosis

What happens during vision screening?

There are several types of vision screening tests.

Vision screening for infants includes checking:

• How well your baby's eyes can follow a moving object, such as a toy
• How your baby's pupils (the black center part of the eye) respond to a bright light
• Whether your baby blinks when a light shines in the baby's eye
• Whether both eyes focus together

Vision screening for children and adults includes:

• Distance vision test. This test is also called a "visual acuity" test. It checks how well you can see things far away. Usually, you'll read rows of letters off a wall chart or a video monitor. Each row of letters is smaller than the one before it. To take the test, you usually stand 20 feet from the chart and cover one eye. You read the letters one row at a time until you get to a row with letters that are too small for you to see. Each eye is tested separately. Some eye charts use a capital E that points in different directions. Special charts for young children may use pictures or symbols.
• Close-up vision test. For this test, you hold a small card about 14 inches away from your face. The card has several lines of printed text that get smaller and smaller. You read the text out loud while using both eyes at the same time. This test checks for farsightedness in children and adults, and for presbyopia in adults.
• Color blindness test. Color blindness means you see colors differently than most people. You may also have trouble telling certain colors apart. Children are usually tested once for color vision. They're shown a picture of colored numbers or symbols in a background of multicolored dots. If they can't see the numbers or symbols, they are color blind.

Will I need to do anything to prepare for vision screening?

If you or your child wears glasses or contact lenses, bring them with you to the screening. Your provider may want to check the prescription.

Are there any risks to screening?

There is no risk to a vision screening.

What do the results mean?

If vision screening shows a possible vision problem or eye disorder, you or your child will likely be referred to an eye care specialist for a more complete eye exam and treatment. This may include getting corrective lenses, vision therapy, or surgery.

Learn more about laboratory tests, reference ranges, and understanding results.