A cataract is a clouding of the eye's lens that causes decreased vision. The lens of the eye focuses light rays onto the retina (the light-sensitive tissue at the back of the eye) where an image is recorded. This allows us to see things clearly. The lens of the eye comprises mostly water and protein. The protein is arranged in a way that keeps the lens clear and lets light pass through it. A cataract develops when some of the protein clumps together and starts to cloud an area of the lens. A cataract won't spread from one eye to the other, although many people develop cataracts in both eyes.
As the cataract matures and gets cloudier, it may become difficult to read and do other normal tasks. Some people with “ripe” cataracts describe their vision as “trying to see through a waterfall.” Many people are not aware that their vision is blurry as cataracts usually progress slowly. That is just one reason why regular comprehensive eye examinations are important.
The exact cause of this clouding is not known. However, a number of factors are known to contribute to the formation of cataracts, including, but not limited to:
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 May 10, 2017.
Cataracts in adults. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T116240/Cataracts-in-adults. Updated November 28, 2016. Accessed May 10, 2017.
Cataracts. Patient website. Available at: https://patient.info/health/cataracts-2. Updated November 20, 2015. Accessed May 10, 2017.
Facts about cataract. National Eye Institute (NEI) website. Available at: https://nei.nih.gov/health/cataract/cataract_facts. Updated September 2015. Accessed May 10, 2017.
What are cataracts? American Academy of Ophthalmology website. Available at: https://www.aao.org/eye-health/diseases/what-are-cataracts. Updated November 15, 2016. Accessed May 10, 2017.
What is a cataract? NIH Senior Health website. Available at: https://nihseniorhealth.gov/cataract/whatisacataract/01.html. Accessed May 10, 2017.
Last reviewed May 2017 by EBSCO Medical Review Board Michael Woods, MD, FAAP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.