Eyes And Vision Flashcards
What are the structures that make up the outer fibrous layer of the eye?
-sclera and cornea
What structure makes up the middle vascular layer of the eye?
-choroid
What structure makes up the inner layer of the eye?
-retina
The exit area on the retina is called?
-optic disk
Why is the optic disk called the blind spot?
-contains no photoreceptors to detect light
What is myopia?
- elongated eye
- image falls before retina
- nearsightedness
-corrected with concave lens
What is hyperopia?
- eyeball is shortened
- image falls behind retina
- farsightedness
-corrected with convex lens
What is emmetropia?
-normal visual acuity
What test is used to examine visual acuity?
-Snellen eye chart
What is astigmatism?
- irregular shape of cornea or lens
- corrected using uneven or cylindrical lenses
What are the muscles of the eye (2)? And what are their functions
- outer radial muscle (dilates eye;sympathetic)
- inner circular muscles (constricts eye;parasympathetic)
What is trichromatic color vision?
- provided by the stimulation of three types of cones, designated blue, green, red.
- colors refer to the region of visible spectrum in which each cones pigment absorbs light best