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Diagnosis of Cataracts

The only way to find a cataract is with an eye exam. A doctor who treats eyes will look at your 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 you see at distances. Your eyesight may also be tested under low contrast or glare.
  • Dilated eye exam—The doctor gives you special eye drops to widen your pupil. 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: Accessed February 8, 2019.
Cataracts in adults. EBSCO DynaMed Plus website. Available at: Updated August 16, 2018. Accessed February 8, 2019.
Facts about cataract. National Eye Institute (NEI) website. Available at: Updated September 2015. Accessed February 8, 2019.
Visual acuity test: performing. EBSCO Nursing Reference Center website. Available at: Updated February 16, 2018. Accessed February 11, 2019.
What are cataracts? American Academy of Ophthalmology website. Available at: Updated November 9, 2018. Accessed February 9, 2019.

Revision Information

  • Reviewer: EBSCO Medical Review BoardJames P. Cornell, MD
  • Review Date: 12/2018
  • Update Date: 02/08/2019
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