To diagnose keratoconus, your eye doctor (ophthalmologist) will review your medical and family history and conduct an eye exam. He or she may conduct other tests to determine more details regarding the shape of your cornea. Tests to diagnose keratoconus include:

  • Eye refraction. In this test your eye doctor uses special equipment that measures your eyes to check for vision problems. He or she may ask you to look through a device that contains wheels of different lenses (phoropter) to help judge which combination gives you the sharpest vision. Some doctors may use a hand-held instrument (retinoscope) to evaluate your eyes.
  • Slit-lamp examination. In this test your doctor directs a vertical beam of light on the surface of your eye and uses a low-powered microscope to view your eye. He or she evaluates the shape of your cornea and looks for other potential problems in your eye.

    The doctor may repeat the test after you've had eyedrops applied to dilate your pupils. This helps with viewing the back of your eye.

  • Keratometry. In this test your eye doctor focuses a circle of light on your cornea and measures the reflection to determine the basic shape of your cornea.
  • Computerized corneal mapping. Special photographic tests, such as optical coherence tomography and corneal topography, record images of your cornea to create a detailed shape map of your cornea's surface. The tests can also measure the thickness of your cornea.
Jan. 30, 2016
  1. Wayman LL. Keratoconus. http://www.uptodate.com/home. Accessed Nov. 24, 2015.
  2. What is keratoconus? American Academy of Ophthalmology. http://www.geteyesmart.org/eyesmart/diseases/keratoconus.cfm. Accessed Nov. 24, 2015.
  3. Keratoconus treatment. American Academy of Ophthalmology. http://www.geteyesmart.org/eyesmart/diseases/keratoconus-treatment.cfm. Accessed Nov. 24, 2015.
  4. van der Worp E, et al. Modern scleral contact lenses: A review. Contact Lens & Anterior Eye. 2014;37:240.
  5. Raiskup F, et al. Corneal collagen crosslinking with riboflavin and ultraviolet-A light in progressive keratoconus: Ten-year results. Journal of Cataract and Refractive Surgery. 2015;41:41.
  6. Jinabhai A, et al. Optical quality and visual performance with customised soft contact lenses for keratoconus. Opthalmic and Physiological Optics. 2014;34:528.
  7. Amayem AF, et al. Refractive and visual outcomes of penetrating keratoplasty versus deep anterior lamellar keratoplasty with hydrodissection for treatment of keratoconus. Cornea. 2013;32:e2.
  8. Keratoconus diagnosis. American Academy of Ophthalmology. http://www.geteyesmart.org/eyesmart/diseases/keratoconus-diagnosis.cfm. Accessed Nov. 24, 2015.
  9. Riggin EA. Allscripts EPSi. Mayo Clinic, Rochester, Minn. July 27, 2015.
  10. Keratoconus. American Optometric Association. http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/keratoconus?sso=y. Accessed Dec. 23, 2015.
  11. Keratoconus. Merck Professional Version. http://www.merckmanuals.com/professional/eye-disorders/corneal-disorders/keratoconus. Accessed Dec. 23, 2015.
  12. Yanoff M, ed., et al. Testing of refraction. In: Ophthalmology. 4th ed. Edinburgh, U.K.: Mosby Elsevier; 2014. https://www.clinicalkey.com. Accessed Oct. 30, 2014.
  13. Yanoff M, ed., et al. Keratoconus and other ectasias. In: Ophthalmology. 4th ed. Edinburgh, U.K.: Mosby Elsevier; 2014. https://www.clinicalkey.com. Accessed Oct. 30, 2014.
  14. Patel SV (expert opinion). Mayo Clinic, Rochester, Minn. Jan. 5, 2016.