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: https://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/cataract?sso=y. Accessed February 8, 2019.
Cataracts in adults. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T116240/Cataracts-in-adults. Updated August 16, 2018. Accessed February 8, 2019.
Facts about cataract. National Eye Institute (NEI) website. Available at: https://nei.nih.gov/health/cataract/cataract_facts. Updated September 2015. Accessed February 8, 2019.
Visual acuity test: performing. EBSCO Nursing Reference Center website. Available at: https://www.ebscoh.... Updated February 16, 2018. Accessed February 11, 2019.
What are cataracts? American Academy of Ophthalmology website. Available at: https://www.aao.org/eye-health/diseases/what-are-cataracts. Updated November 9, 2018. Accessed February 9, 2019.
Last reviewed December 2018 by EBSCO Medical Review BoardJames P. Cornell, MD
Last Updated: 2/8/2019

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