Welcome to Johns Hopkins Health Alerts!

"Johns Hopkins Health Alerts is an excellent site and I have recommended it to several of my friends. Thanks again, and keep up the good work!"
  • - D. Ambrosio


This free public service from Johns Hopkins Medicine helps keep you up to date on the latest breakthroughs for the most common medical conditions which prevent healthy aging.

Get the latest news sent straight to your inbox for FREE. Check all the boxes below for the topics that interest you.
We value your privacy and will never rent your email address

Johns Hopkins Health Alert

How Cataracts Affect Your Vision

Comments (0)

Sooner or later many of us will develop a cataract.  Here in brief is an explanation of how cataracts affect vision. 

Although the eyes are extremely complex organs, the principles of vision are quite simple: By adjusting, focusing and processing the light that reflects off objects, your eyes work in conjunction with your brain to allow you to see the world around you. 

As light rays enter the eye, they first pass through the clear, protective cornea. Muscles in the iris (the colored part of the eye) contract or expand the pupil to adjust the amount of light entering the eye. The lens (a transparent, elastic structure) focuses the light to produce a sharp image on the retina (the layer of nerves lining the back of the eye). When light hits the retina, it is transformed into electrical signals that travel through the optic nerve to the brain, which interprets these signals as a visual image. 

A cataract clouds the lens of the eye, interfering with clear vision. A healthy lens, which consists primarily of water and protein, is transparent. With age, however, changes occur in the lens -- including the clumping together of proteins and other chemical transformations -- that can lead to the development of a cataract. The resulting opacity scatters the light entering the eye, so that the light reaching the retina is diffuse rather than focused and precise. 

The extent of a cataract's effect on vision depends largely on its location. 

  • Cataracts covering the entire lens or those in the center of the lens (nuclear or posterior subcapsular cataracts, respectively) result in symptoms such as blurred vision, double vision and sensitivity to light and glare. 
  • Cataracts located on the outer edge of the lens may cause only slight visual disturbances that might not be noticed. 

Posted in Vision on May 27, 2011


Medical Disclaimer: This information is not intended to substitute for the advice of a physician. Click here for additional information: Johns Hopkins Health Alerts Disclaimer


Notify Me

Would you like us to inform you when we post new Vision Health Alerts?

Post a Comment

Comments

Health Alerts registered users may post comments and share experiences here at their own discretion. We regret that questions on individual health concerns to the Johns Hopkins editors cannot be answered in this space.

The views expressed here do not constitute medical advice, and do not represent the position of Johns Hopkins Medicine or Remedy Health Media, LLC, which has no responsibility for any comments posted on this site.


Post a Comment


Already a subscriber?

Login

Forgot your password?

New to Johns Hopkins Health Alerts?

Register to submit your comments.

(example: yourname@domain.com)

Customer Service

Registered Users Log-in:

Forgot Password?

Become a Registered User!
It's fast and FREE!
The Benefits of Being a Registered User

Johns Hopkins' Vision Bestsellers

Controlling Glaucoma to Prevent Vision Loss

Written by Harry A. Quigley, M.D., Director of the Dana Center for Preventive Ophthalmology at the acclaimed Wilmer Eye Institute at Johns Hopkins, Controlling Glaucoma to Prevent Vision Loss provides straightforward answers to your most important questions about managing glaucoma, a condition that affects an estimated 2.5 million Americans. Controlling Glaucoma to Prevent Vision Loss discusses everything you need to know about glaucoma: its possible causes, the current methods for diagnosing it, and the many options that you have to treat it, from eye drops to laser surgery. If you or a loved one has glaucoma, our new report will give you the information you need to make informed treatment decisions that could save your sight. Read more or order the INSTANT PDF DOWNLOAD

 


Johns Hopkins Vision White Paper 2013

2014 Vision White Paper
Written by Dr. Susan B. Bressler, professor of ophthalmology at the acclaimed Wilmer Eye Institute, and a team of top Johns Hopkins doctors, this comprehensive report is essential reading for anyone affected by a vision disorder, including low vision, cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy.
Read more or order now




Johns Hopkins White Papers

2014 Diabetes White Paper
The Diabetes White Paper teaches you how to manage Type 1 and Type 2 diabetes and avoid complications, such as nerve damage, heart disease, kidney failure, and retinopathy. This comprehensive report explains the basics of how your body metabolizes glucose and reviews the latest medications and tools for monitoring your blood glucose. Includes diagrams, glossary, and recent research.
Read more or order now

Health Topic Pages

  • Health Alert
  • Special Report

What is this?

XML