OPTH Lec03 Flashcards
What are the characteristics of glaucoma?
Characterized by arcuate visual field defects that correspond to optic nerve damage. Involves elevated IOP (but IOP CAN be normal)
What is normal IOP?
8-21 mmHg
What is the normal course of aqueous in the eye?
Aqueous is produced by the ciliary body percolates through the conules over the lens, across the pupil into the AC and exits through the trabecular meshwork into the canal of Schlemm into episcleral veins
What causes glaucoma?
When the flow of aqueous is altered
What is the most common form of glaucoma?
open angle
What does Acute narrow angle glaucoma do?
Causes sudden elevated IOP by mechanical blockage of flow. Medical emergency
What is angle closure glaucoma?
When the canal of schlemm is occluded and the aqueous cannot flow out.
What are characteristics of optic nerve problems?
PAIN, colored halos around lights, red eye with tearing and steam cornea, mid fixed and ciliated pupil, nausea, vomiting, chest pain, firm eye to palpation
What is the path of the optic nerve?
Nerve fibers will begin as retinal ganglion cells and become a nerve fiber layer gathering at the optic nerve. They will travel retro orbitally to and through the sphenoid optic canal, cross in the optic chiasm and end in the lateral geniculate body
What can cause damage to the optic nerve?
interruption of blood flow to nerve fibers at the optic nerve head or mechanical pressure pushing the nerve fibers against the lamina cribrosa which will interrupt axoplasmic flow
What are risk factors of glaucoma?
over 40 years of age, black race, family history, chronic steroid us, cup to disc ratio of 0.5 or more, asymmetry
What do you examine when assessing for glaucoma?
optic nerve but unless there is extreme visual loss will not be found on confrontation VF
What is this?
Enlarged chronic nerve due to glaucoma
What is cataracts associated with?
age related, congenital, traumatic, nutritional, environmental or systemic