What are they?

Some common vision tests are visual acuity tests, refraction, visual field tests, and colour vision tests.

Visual acuity (sharpness) tests

These tests are used:

• To see if your child needs glasses or contact lenses.
• To check for eye problems, such as a lazy eye (amblyopia) or misaligned eyes (strabismus).
• To monitor an eye problem that a child already has.
• To check an eye injury.

Visual field tests

These tests are used:

• To check for vision loss in any area of your child's range of vision.
• To screen for certain eye diseases.
• To look for nerve damage after a head injury, a stroke, or some other problem that could reduce blood flow to the brain.

Refraction and colour tests

• A refraction test is done to find the right prescription for glasses and contact lenses.
• A colour vision test is done to check for colour blindness.

How are these tests done?

Visual acuity test

For this test, your child:

• Covers one eye at a time.
• Reads aloud from a chart across the room. The chart may have letters or pictures on it.

For very young children, the doctor will test vision in other ways. For example, the doctor may check to see how well your child's eyes can track a face or other object as it moves.

Refraction

• Your child looks into a special device.
• The device puts lenses of different strengths in front of each eye to see how strong your child's glasses or contact lenses need to be.

Visual field tests

• The doctor may have your child look through special machines.
• Or the doctor may simply have your child stare straight ahead while the doctor moves a finger into and out of your child's field of vision.

Colour vision test

• Your child looks at pieces of printed test patterns in various colours. Your child says what number or symbol they see.
• The doctor may have your child use a pointer to trace the number or symbol.

How do these tests feel?

There is very little chance of having a problem from this test. If dilating drops are used for a vision test, they may make the eyes sting and cause a medicine taste in the mouth.