Most eye problems are diagnosed through a vision test. This is a standardized examination used to evaluate and monitor a child’s vision and to detect potential diseases or disorders that may affect the eyes. The exact nature of a vision test varies depending on the child’s age and any suspected vision problems.

A pediatrician, ophthalmologist (eye physician) or other trained eye specialist will regularly perform various tests of a child’s vision from the time a child is born until around the age of 5 years, with checkups every year or two years. These tests include:

• Visual acuity test. The child reads an eye chart that helps determine the strength of vision at various distances.
  
  
• Visual field test. Measures a child’s peripheral (or side) vision.
  
  
• Tonometry test. Uses a simple puff of air blown on the child’s eye to check the fluid pressure inside the eye.

Many eye problems – such as amblyopia, strabismus and refractive errors – are first detected during preschool vision screening, in which an acuity chart is used to test a child’s eyesight.

In other cases, parents may bring a child to a physician because of certain symptoms that are affecting the child. Parents who notice their child struggling with vision difficulties are urged to set up an appointment with a physician promptly. Early diagnosis of vision problems often can keep these disorders from becoming permanent.

A physician will conduct a physical examination. In addition to performing a vision test, the physician may observe a child’s eye motion, look for physical manifestations on the eyelids and test the reaction of pupils to light. Parents will be asked to provide information about the child’s medical history and list of symptoms. Parents who can present an accurate and complete account of a child’s symptoms will greatly aid in this process. This information is crucial to helping the physician distinguish the source of a condition.

In evaluating a newborn, a physician will ask the parent for a full prenatal history. Likely questions include those about developmental delays, maternal infections (e.g., herpes simplex virus, cytomegalovirus, chlamydia, human immunodeficiency virus), and any complications with delivery. Some medications given to infants at childbirth, including silver nitrate (an ophthalmic antiseptic used to treat chlamydial infection) and erythromycin (an antibiotic), also are known to cause eye irritation.