glaucoma

Question 1

What are the clinical findings in glaucoma?

Answer 1

increased intraocular pressure
increased cup:disc ratio (enlarged cup)
visual field defects

Question 2

What is the pathway of aqueous humor?

Answer 2

Production and secretion from the ciliary body -> flow into the posterior chamber -> flow into the anterior chamber ->
principle pathway: trabecular meshwork -> canal of Schlemm -> lacrimal duct
uveoscleral pathway: seeps through, around, and between tissues of the ciliary muscle and sclera

Question 3

What are the two main approaches to decreasing intraocular pressure/treating glaucoma?

Answer 3

decrease aqueous humor production

increase aqueous humor outflow (uveoscleral pathway or canal of Schlemm)

Question 4

What drugs increase aqueous humor outflow through the uveoscleral pathway? What drugs increase aqueous humor outflow through the Canal of Schlemm?

Answer 4

uveoscleral pathway - prostaglandin agonists (e.g. latanoprost)
Canal of schlemm - cholinergic agonists (e.g. carbachol, pilocarpine)

Question 5

What drugs decrease aqueous humor production?

Answer 5

beta blockers - timolol
alpha2 agonists - brimonidine
carbonic anhydrase inhibitors - dorzolamide

Question 6

Why do cholinergic agonists increase aqueous humor outflow?

Answer 6

Contraction of the ciliary body pushes AH through the trabecular network, facilitating aqueous humor outflow through the canal of Schlemm. The ciliary body is controlled by parasympathetics nerves which release ACh from post-ganglionic nerves.