Physiology of vision
Convex lens, concave lens, lasik surgery, custom shape adjustment lens
Treatment to eye problems
Lasik surgery
Treats all problems by reshaping cornea in order to properly focus light on retina
Custom shape adjustment
Treats astigmatism
Convex lens
Treats farsightedness
Concave lens
Treats nearsightedness
Nearsighted vision (myopia)
Normal close up vision; blurry distant vision Eye is too long & the light waves focus in front of retina
Steps
1. Light waves collected by cornea 2. Waves transmitted through aqueous humor, pupil, lens, vitreous humor, retina 3. Visual information leaves eye via optic nerve 4. Sent to thalamus 5. Relayed to occipital lobe for integration
Presbyopia
Age related farsightedness because lens loses elasticity & cannot accommodate. Difficulty seeing in dim light & reading fine print
Astigmatism
Blurry vision at any distance due to irregular shape or cornea. It causes too much light to focus at multiple points
Pupil
Changes size to regulate the amount of light that enters the eye. Protects retina from sudden, intense light
Iris
Ciliary muscles that regulate pupil size
Automatic adjustment of lens
Clear vision relies on______ (aka accommodation) to bring an image to focus on the retina
Normal vision (emmetropia)
Correct shape to focus light waves on retina
Farsighted vision (hyperopia)
Normal distant vision; blurry close up vision Eye too short; light waves focus behind retina
Divergence
Eye movement laterally when viewing objects at a distance
Convergence
Eye movement medially when viewing objects up close
Vision
Perception of how light waves are integrated
Circular muscles
Produce constriction
Radial muscles
Produce dilation
Convex shape
Refracts (bends) light & focuses it at a specific point (focal point)
Distant vision
Requires a longer focal length to focus images directly on the retina (lens needs to become thin & flat)
Close vision
Requires a shorter focal length to focus images more directly on the retina (lens needs to become more round)
