Why It Is Done

Visual acuity tests may be done:

• As part of a routine eye exam to screen for vision problems. How often you should have routine eye exams changes as you age. For more information, see:
  • Eye exams for adults.
  • Eye exams for children and teens.
• To monitor an eye problem, such as diabetic retinopathy.
• To determine if you need glasses or contact lenses to improve your vision.
• After an injury to the eye.
• When you obtain or renew your driver's license or for some types of employment.

Refraction is done:

• To determine the correct prescription for eyeglasses or contact lenses.

Visual field tests may be done:

• To check for vision loss in any area of your visual field.
• To screen for eye diseases, such as macular degeneration and glaucoma, which cause gaps in the visual field.
• To look for damage to the nerves of the eye following a stroke, head injury, or other condition that causes reduced blood flow to the brain.

Color vision tests may be done:

• As part of a routine eye exam.
• To screen for or diagnose color blindness.
• To screen applicants for jobs in which color perception is important, such as truck driving, electronics, or the military.