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Diagnosis of Cataracts

  • Cynthia M. Johnson, MA
Publication Type:

Condition InDepth

Diagnosis of Cataracts

The only way to find a cataract is with an eye exam. A doctor who treats eyes will look at a person's lens. Other tests look at the structure and health of the eye. A full eye exam will have:

  • A visual acuity test—This eye chart test measures how well a person can see at distances. Eyesight may also be tested under low contrast or glare.
  • Dilated eye exam—Special eye drops are given to widen the pupils. This lets the doctor see the lens and the structures of the back of the eye.
  • Slit lamp exam—This is an exam of the eye using a microscope that magnifies the eye.
  • Tonometry—This is a test to measure fluid pressure inside the eye (too much pressure may be a sign of glaucoma).


  • Cataract. American Optometric Association website. Available at: https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/cataract?sso=y. Accessed May 2, 2022.
  • Cataracts. National Eye Institute website. Available at: https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/cataracts. Accessed May 2, 2022.
  • Cataracts in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/cataracts-in-adults. Accessed May 2, 2022.
  • What are cataracts? American Academy of Ophthalmology website. Available at: https://www.aao.org/eye-health/diseases/what-are-cataracts. Accessed May 2, 2022.


  • James P. Cornell, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.