Sense of sight
Vision occurs when light is processed by the eye and interpreted by the brain. Light passes through the transparent eye surface (cornea). The pupil (the black opening in the front of the eye) is an opening to the eye interior. It can get larger or smaller to regulate the amount of light entering the eye. The colored portion (iris) is really a muscle controlling the pupil size. The inside of the eye is filled with a gel-like fluid. There is a flexible, transparent lens that focuses light so it hits on the back of the eye (the retina). The retina converts light energy into a nerve impulse that is carried to the brain and then interpreted.
Last reviewed 11/10/2012 by David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.
- The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
- A licensed medical professional 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.
Any duplication or distribution of the information contained herein is strictly prohibited.