January 8 Lecture - January 8, 2009 Anatomy of the Eyeball-...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the 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.

Page1 / 6

January 8 Lecture - January 8, 2009 Anatomy of the Eyeball-...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online