give up liao Flashcards
What is vision
To perceive and interpret their surrounding environment through their eyes
What are the dioptric system of the eye
Cornea, Aqueous humor, crystalline lens, vitreous humor
what are the different refractive errors
myopia, hyperopia, astigmatism, presbyopia
concave lens is used to correct?
myopia
convex lens is used to correct?
hyperopia
what are the causes of myopia
long axial length, steep corneal curvature, steep crystalline lens curvature
causes for hyperopia
short axial length, flat corneal curvature, flat crystalline lens curvature
what is simple myopic astigmatism
one of the principal meridian is formed on the retina while the other is formed in front of the retina
compound myopic astigmatism
both meridians are formed in front of the retina.
simple hyperopic astigmatism
one meridian is formed on the retina while the other is formed behind the retina.
mixed astigmatism
one meridian is formed on in front of the retina while the other is formed behind the retina
compound hyperopic astigmatism
both meridians are formed behind the retina
cataract
clouding of the crystalline lens which is often due to aging
glaucoma
increased pressure within the eye which could damage the optic nerve
AMD
cause blurred or distorted vision