anatomy final - vision Flashcards
(11 cards)
Accommodation
Rounding of lens for near vision
Refraction
Bending of light rays (necessary for focus) from air, cornea, aqueous humor, lens, vitreous humor.
Myopia
Nearsightedness - eyeball is too long, so image focuses in front of fovea.
Hyperopia
Farsightedness - eyeball is too short and image focuses behind fovea.
Presbyopia
Failure of lens to accommodate. Lens remains flat for far vision. It loses elasticity. This is what happens for old farts.
Constriction of pupil
Improves depth of field.
Convergence
Focusing both eyes on same object. Improves depth perception.
Rods
Photoreceptors for dim, black and white vision. Located all over retina except fovea.
Dark adaptation
Adjustment to change from bright light to dim light.
Cones
Photoreceptors for detailed color vision. Most concentrated in macula lutea.
Light adaptation.
Adjustment to change from darkness to light.