Retina

Eye

The eye is the organ of sight, a nearly spherical hollow globe filled with fluids (humors). The outer layer or tunic (sclera, or white, and cornea) is fibrous and protective. The middle tunic layer (choroid, ciliary body and the iris) is vascular. The innermost layer (the retina) is nervous or sensory. The fluids in the eye are divided by the lens into the vitreous humor (behind the lens) and the aqueous humor (in front of the lens). The lens itself is flexible and suspended by ligaments which allow it to change shape to focus light on the retina, which is composed of sensory neurons.

Definition

The retina is the light-sensitive layer of tissue at the back of the inner eye. It acts like the film in a camera -- images come through the eye's lens and are focused on the retina. The retina then converts these images to electric signals and sends them via the optic nerve to the brain.

The retina is normally red due to its rich blood supply. An ophthalmoscope allows a health care provider to see through your pupil and lens to the retina. If the provider sees any changes in the color or appearance of the retina, it may indicate a disease.

Anyone who experiences changes in sharpness or color perception, flashes of lights, floaters, or distortion in vision should get a retinal examination.

References

Fay A. Diseases of the visual system. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 449.

See also:

Review date:
May 21, 2009
Reviewed 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 David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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