26 Lens

Structures

• cornea sits on top of pupil

• lens sits behind pupil

• both work together

• elongated fiber cells perform anaerobic metabolism

Accommodation

Pathology

Presbyopia

Refractive errors

• corneal does most of refractions, has to bend lights to set on the retina

• sometimes while growing, corneal curvature isn't grown right

Myopia

• negative lens spreads light out

Hyperopia

• like a magnifying glass

Astigmatism

• normal cornea circular

• astigmatism: cornea shaped like football, horizontal focus different from vertical focus

Ectopic Lentis

Cataracts

• RA taking steroids

• Also diabetes and galactose deficiency

• Marfan a risk

Aldose Reductase

• aldose reductase found in lens of eye

• diabetes/galactose problem: lots of conversion to sorbitol/galactitol

• draw in fluid, increase lens osmolarity

Diabetes

Galactose