Anatomy of the Eye By: Kaitlyn Stevens, Nicole Morgan, Cayla Campbell, Blake Rogers, Megan Simpson

Parts of the Eye http://www.medicinenet.com/image-collection/eye_anatomy_detail_picture/picture.htm

Parts of the Eye Explained Retina- light-sensitive inner lining of the back of the eye Cornea- clear front surface of eye, part of the eye that primarily focuses light Iris- functions like diaphragm of a camera, controls amount of light reaching the back of the eye by adjusting the size of the pupil Anterior Chamber- space between cornea and iris Lens- located directly behind the pupil and focuses light Posterior Chamber- region behind the iris

Parts of Eye Continued Ciliary body- controls ciliary muscle, controls shape of lens and ciliary epithelium Aqueous humor- slightly alkaline liquid that occupies the anterior and posterior chambers of the eye Suspensory ligaments- ligament that supports a body part Vitreous humor- transparent, colorless, gelatinous mass that fills the space between the lens of the eye and the retina lining the back of the eye

Parts of Eye Continued Choroid coat- vascular layer of the eye lying between the retina and the sclera Sclera- “white part of eye”, fibrous, protective, outer layer of eye made of collagen and elastic fibers Optic disc- raised disk on retina at point of entry of optic nerve, lacks visual receptors and creates a blind spot

Function of Eyelid Eyelids protect eye from dirt, dust, bright light, and foreign matter Eyelids also help spread tears over surface of eye Lacrimal Apparatus produces tears http://marineyes.com/anatomy/eyelid.html

Structures of the eye Light rays enter the eye through the cornea, the clear front “window” of the eye. The cornea’s refractive power bends the light rays in such a way that they pass freely through the pupil the opening in the center of the iris through which light enters the eye.

Function of Extrinsic Eye Muscles Some of the fastest contracting and most precisely controlled skeletal muscles in the human body Function as Agonist & Antagonists pairs to move the eyeball

Accommodation Lens helps the eye automatically focus on near and approaching objects, like an autofocus camera lens.

Refraction change in direction of propagation of any wave as a result of its traveling at different speeds at different points along the wave front. •measurement of the focusing characteristics of an eye or eyes.

Refractive Disorders Eyeglass lenses correct refractive errors by focusing light directly on the retina. The type of lens depends on the type and severity of the refractive error. The strength of a lens (i.e., its refractive power) is measured in optical units called diopters. This measurement indicates how much refractive power the lens must have to focus images directly on the retina. The higher the diopter, the stronger the lens.

Structure of the Retina Retina contains visual receptors called photoreceptors (rods and cones) 3 layers Outer- Photoreceptors (rods & cones) Middle-Bipolar neurons Inner-Ganglion cells (axons join & form optic nerve) Light passes through ganglion and bipolar neurons before reaching photoreceptors Rods are abundant in the periphery of the retina whereas cones are found more frequently in the central areas Phototransduction is conversion of light stimuli into neural signals 1. Photopigment absorbs light & breaks down to 2 components 2. Hyperpolarizes rods/cones 3. Decrease in release of inhibitory neurotransmitter Fibers partially cross over in optic chiasm- Right half of brain interprets image from left eye and vice versa

Optical illusions http://www.illusions.org/ http://www.michaelbach.de/ot/

Sources Bogi, Stephen. "Human Eye Anatomy: Parts of the Eye." All About Vision. N.p., Feb. 2014. Web. 12 Apr. 2016. "Anatomy of Your Eye ." Clarkson Eyecare . Clarkson Eyecare, 2014. Web. 12 Apr. 2016 Dahl, Andrew. "Anatomy of Eye:Eyelids and Eyelaashes ." emedicinehealth . Ed. William C. Shiel. N.p., 7 Apr. 2016. Web. 12 Apr. 2016. http://www.healthcommunities.com/refractive-errors-and-vision/refractive-errors- correction-overview.shtml#sthash.nE5Xsrr7.dpuf Moresea’s Powerpoint