Home > Medical Reference > Encyclopedia (English)

Toggle: English / Spanish

< Back
External and internal eye anatomy

The cornea allows light to enter the eye. As light passes through the eye the iris changes shape by expanding and letting more light through or constricting and letting less light through to change pupil size. The lens then changes shape to allow the accurate focusing of light on the retina. Light excites photoreceptors that eventually, through a chemical process, transmit nerve signals through the optic nerve to the brain. The brain processes these nerve impulses into sight.
  • Review Date: 3/5/2007
  • Reviewed By: Daniel Kantor, M.D., Director of the Comprehensive MS Center, Neuroscience Institute, University of Florida Health Science Center, Jacksonville, FL. Review provided by VeriMed Healthcare Network.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2007 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

adam.com
     
Physician Directory

Physician Specialties

Medical Glossary

Guide for Patients

Guide for Visitors

    
About Us     ·     Contact Us     ·     Phone Listing     ·     Residency Programs     ·     Site Map     ·     Site Search     ·     Links     ·     FAQs

© 2008 Maryland General Hospital, All Rights Reserved   ·   827 Linden Avenue,   Baltimore, MD 21201   ·   410-225-8000
Commitment to Compliance   ·   Privacy Policy   ·   Terms and Conditions of Use   ·   Disclaimer   ·   JCAHO Public Notice