cell biology :vision Flashcards
1
Q
where does light enter first?
A
cornea
2
Q
what a feautres of cornea?
A
limited blood supply , highly innervated , maintain most refractive component in the eye.
3
Q
what are features of the lens?
A
focus near and far objects , no nerves , no direct blood supply , good cellular organisation.
4
Q
what causes myopia(short sightedness)?
A
the cornea and lens together bend light too strongly , reults in image being focused before retina.
5
Q
how do u calculate lens power
A
1/v - 1/u = 1/f
6
Q
what causes long sightedness?
A
refracttuve suystem are too weak or eye is too short
7
Q
what causes presbyopia and how do you treat it?
A
elasticity is lost , cannot focus near or far objects rquire bifocal spectacles
