This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: January 8, 2009 Anatomy of the Eyeball- On the back of the eye ball at the retinal layer is a depressed area known as the fovea centralis . o The region immediately surrounding the fovea centralis is the macula lutea- Medial to the fovea centralis , is the optic disc or blind spot where there are no rods or cones o This is the area where the optic nerve exits from the eyeball o Not consciously aware of this in most cases Pg. 584 • As you bring the page closer to the eye ball, the eye has to converge to focus on the edge, which shifts the image horizontally across the eye Convergence : the medial movement of the eyeball Viewing and Image- A vertical image will be upside down on the eye ball- A horizontal image will be viewed as if in a mirror- The brain centres in the cerebral cortex will rearrange the image to its appropriate orientation via association- The light rays must move through the lens of the eye and be refracted onto the area of the retina- Three ___ in focusing light rays on the fovea centralis o Refraction: the bending of light rays so that they strike the intended area of retina Accomplished by a number of structures • Cornea (as light passes through it will be bent by a certain degree or magnitude) o The cornea is more dense than air so it will bend the light rays according to a certain index o Refractive index is the relative speed at which the light moves through the cornea when compared to its speed in air o R.I > 1 • Anterior and posterior region to the iris is filled with a fluid substance known as the aqueous humor which has a refractive index as well • The rays will then strike the lens which will further bend the light • The posterior cavity of the eye (behind the lens and in front of the retina) has a substance known as vitreous humor , a thick gelatinous consistency, after the light passes through this the light will strike...
View Full Document
This note was uploaded on 10/23/2011 for the course BIOL 2125 taught by Professor Dr.park during the Winter '02 term at A.T. Still University.
- Winter '02