Lecture 13 3/31/25 Flashcards
What is an etiologic diagnosis?
description of what is causing the morphologic diagnosis
What is the only etiology for primary glaucoma?
goniodysgenesis
What are the characteristics of latanoprost?
-very potent and rapidly acting IOP-lowering agent
-though to reduce aqueous production and increase aqueous outflow
-typically works within 1 hour and can cause very dramatic drops in IOP
-also a very potent miotic/pupil constrictor
What are the characteristics of timolol?
-topical beta-blocker
-IOP lowering agent that works by reducing aqueous production
-not very potent
Why is a topical beta-blocker used in the “good” eye in patients with glaucoma?
use of a topical beta-blocker can delay the onset of glaucoma in the eye not presenting with clinical signs by about 2 years
Why should a patient be checked two hours after the start of glaucoma therapy?
-optic nerve damage is an event with temporal importance
-if the treatment has not lowered the IOP by the 2 hour mark, other therapies can be done to try and reduce pressure
-waiting longer for a recheck risks the patient’s vision permanently if the therapy happens to not work
What is the typical recheck schedule for a patient following glaucoma treatment and the start of therapy?
-2 hrs
-24 hrs
-48 hrs
-1 week
-2 weeks
-1 month
-quarterly
What is important regarding the when latanoprost can be used?
latanoprost can be used both as emergency therapy and as maintenance therapy in eyes that have already developed glaucoma
What is important to note regarding glaucoma relapse?
even on latanoprost/other therapy, it is possible to see a return of high IOP
What are the characteristics of a cupped optic nerve head?
-posterior depression of optic nerve head in response to elevated pressure
-indicates degree of chronicity
-occurs because of hydrostatic pressure on the nerve
-can turn into optic nerve atrophy with sustained high IOPs, at which point vision loss cannot be reversed
Why does pathology in the anterior segment cause elevated IOP in the region of the optic nerve?
due to Pascal’s Law; pressure change anywhere within a confined, incompressible fluid is transmitted throughout the fluid to cause the same change everywhere
What are the characteristics of mannitol?
-emergency therapy for glaucoma
-given slowly via IV
-osmotic diuretic that draws water out of the aqueous and vitreous humors and into the intravascular space
-emergency therapy only, NOT for maintenance
What are the characteristics of dorzolamide?
-carbonic anhydrase inhibitor; inhibits enzyme in the nonpigmented ciliary body epithelium that is essential for aqueous humor production
-reduces aqueous production
-very rapidly acting
-more potent than timolol, less potent than latanoprost
-often used in combo. with timolol
What are the characteristics of a glaucoma drainage valve?
-device that allows aqueous humor to bypass non-functional iridocorneal angle
-consists of a silicone straw with a plastic body attached
-plastic body is sutured directly to sclera
-hypodermic needle is used to create tunnel into anterior chamber to insert straw into
What are the characteristics of glaucoma drainage valve failure?
-can fail early on due to fibrin accumulation in the straw
-anti-fibrotic medications can be used to prevent the straw from clogging and break up clots
-can fail later due to scar tissue formation around the plastic body
-always fails, more a question of when
-typically works for about a year
What are the characteristics of buphthalmia?
-enlarged globe
-can only be caused by chronic glaucoma
-IOP must be high for a sustained period of time for this to occur
-by the time it occurs, the optic nerve has died
What are the characteristics of posterior lens luxation?
-buphthalmic globe leads to stretching and breaking of ciliary zonules
-breaking results in subluxation of the lens
-lens luxation secondary to primary glaucoma is always associated with chronic glaucoma and buphthalmia
-lens is typically behind the iris when a secondary luxation occurs
What are the options for providing comfort to a patient with buphthalmia?
-continued medical therapies
-enucleation
-evisceration with silicone prosthesis
-intravitreal gentamicin injection
