How Is a Cataract Diagnosed?

By Tina D. Turner, M.D.

An ophthalmologist or optometrist diagnoses a cataract by doing a comprehensive medical eye examination, which should include all of the following components:

A Health and Medication History

  • Your overall heath and that of your immediate family
  • The medications you are taking (prescription and over-the-counter)
  • Questions about high blood pressure (hypertension), diabetes, smoking, and sun exposure

A Vision History

  • How well you can see at present, including any recent changes in your vision.
  • Eye diseases that you or your family members have had, including macular degeneration and glaucoma.
  • Previous eye treatments, surgeries, or injuries
  • The date of your last eye examination

A Refraction, or Visual Acuity Testing

a phoropter
  • Distance and near vision acuity tests to determine the sharpness or clarity of your reading and distance vision
  • Testing your vision with different lenses (sometimes contained in a machine called a phoropter, pictured at right) to determine if your vision can be improved or corrected with regular glasses or contact lenses.

Visual Field Testing

  • To determine how much side (or peripheral) vision you have and how much surrounding area you can see.
  • The most common type of visual field test in a regular eye exam is called a confrontation field test, in which the doctor briefly flashes several fingers in each of the four quadrants of your visual field while seated opposite you.

An Eye Health Evaluation

  • An examination of the external parts of your eyes and your lens, using a special microscope called a slit lamp. Your doctor will look for a yellowing of the lens, clefts/fissures, or white opacities that indicate the presence of cataracts.
  • A dilated eye (or fundus) examination, which includes the use of an ophthalmoscope. Special eye drops, such as tropicamide, will dilate, or open, your pupil, which allows the doctor to observe the internal parts of your eye, including the retina and optic nerve.
  • A test of the fluid pressure (or aqueous humor) within your eyes.

Individuals who are over 40 should have a dilated eye examination from an ophthalmologist or optometrist at least every two years. African Americans and/or individuals with a family history of glaucoma who are over 35 should have a dilated eye examination from an ophthalmologist or optometrist every year.

Please note: While an ophthalmologist or optometrist can diagnose a cataract, only an ophthalmologist is qualified to perform cataract surgery.

Personal Stories

  • Paul and Dorothy Johnson: A Daughter's Story
    Read Paul and Dorothy Johnson's story, written by their adult daughter. Dorothy had cataracts and Paul had macular degeneration and diabetes. Learn how the Johnsons and their daughter made the decision to live together.

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