Periodic eye exams are an important part of preventive health care. Many eye and vision problems have no obvious symptoms, so you might not know a problem exists. Early diagnosis and treatment of eye and vision problems can help prevent vision loss.

The American Optometric Association recommends that a child’s first eye exam be done at six months of age with another eye exam every year or two afterwards throughout his or her life.

A comprehensive eye exam includes …

  • A patient history
  • Visual acuity measurements to determine how clearly each eye is seeing
  • A look at the eye’s health, such as side vision; how pupils respond to light; and how the eyes focus, move and work in unison
  • A test to measure the curve of the cornea
  • A look at the optic nerve to test for the presence of glaucoma
  • A look at the retina for signs of problems, such as macular degeneration
  • Refraction tests to determine the lens power a patient will need to compensate for any refractive error – nearsightedness, farsightedness and astigmatism (blurred vision)
  • Other tests, based on the results of the previous tests  
  • (See videos, below, about comprehensive eye exams.)

More on visual acuity

The results of visual acuity testing are written as a fraction, such as 20/40. The top number in the fraction is the standard distance at which testing is done (20 feet). The bottom number is the smallest letter size you were able to read. A person with 20/40 visual acuity would have to get within 20 feet to see a letter that should be seen clearly at 40 feet. Normal distance visual acuity is 20/20. (See video, below.)

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