Glaucoma Flashcards
What is glaucoma?
eye condition that causes progressive degeneration of the optic nerve
-loss of nerve tissue –> gradual, irreversible vision loss –> blindness
What are the types of glaucoma?
primary open-angle glaucoma
angle-closure glaucoma
secondary glaucoma
normal-pressure glaucoma
What is secondary glaucoma?
occurs as a result of an injury, infection, or tumor in or around the eye that causes increased fluid pressure
What is normal-pressure glaucoma?
optic nerve becomes damaged despite normal eye pressures
-unclear why this happens ?sensitive optic nerve or insufficient blood supply
What is primary open-angle glaucoma?
increased production or decreased drainage of aqueous fluid within the eye –> increased IOP –> damage to optic nerve
Describe the typical development of primary open-angle glaucoma.
develops gradually and painlessly - in early stages, can only be diagnosed by eye exam
-by the time vision is impaired, damage is irreversible
Which type of glaucoma is most common?
primary open-angle glaucoma
-accounts for > 90% of cases
What are the risk factors for open-angle glaucoma?
elevated IOP (> 21 mmHg in at least one eye)
older age
family history
African descent
myopia
hypertension
diabetes
migraines
previous intraocular surgery
blunt or penetrating eye trauma
corticosteroids (systemic > ophthalmic > inhaled or intranasal)
What is the only modifiable risk factor for open-angle glaucoma?
elevated IOP
What is angle-closure glaucoma?
occurs when the iris bulges forward to block the drainage angle formed by the cornea and iris
-aqueous fluid cannot drain –> acute, severe increased IOP –> optic nerve damage
-much less common
What should be done if a pharmacist identifies a case of angle-closure glaucoma?
refer to ER or ophthalmologist for urgent care
medical emergency
What is the treatment for angle-closure glaucoma?
eye drops/oral medications acutely to lower IOP
ASAP - laser surgery to widen the drainage angle
What are the signs and symptoms of angle-closure glaucoma?
severe eye pain
eye redness
blurred vision, halos around lights
nausea and vomiting
headache
What are the risk factors for angle-closure glaucoma?
increased age
female
positive female or family history
Asian or Inuit descent
hyperopia
proliferative diabetic retinopathy
topiramate use
What is the caution that many anticholinergics carry regarding eyes? Who is this warning important for?
to avoid in individuals with “glaucoma”
-this is only important for patients with acute angle-closure glaucoma
-not relevant with open-angle glaucoma or those surgically treated with angle-closure glaucoma
What are the goals of therapy for glaucoma?
prevent, halt or slow vision loss
preserve the structure and function of the optic nerve
improve or maintain functional vision
acute angle closure: eliminate pain and other associated symptoms
What does the treatment of open-angle glaucoma focus on?
reducing intraocular pressure
How is target IOP determined?
extent of glaucomatous damage
-amount of disc cupping
-vision loss
the estimated IOPs associated with that damage
the burden of therapy to achieve the desired IOP
target IOP further reduced if damage to optic disc or visual field progresses
What are the different classes of topical agents to treat open-angle glaucoma?
prostaglandin analogues
beta-blockers
alpha-2 adrenergic agonists
carbonic anhydrase inhibitors
cholinergic agonists
What are examples of prostaglandin analogues?
latanoprost
travaprost
bimatoprost
What is the MOA of prostaglandin analogues?
prostaglandin F2-analogues which increase aqueous humor outflow
What is the first line therapy for open angle glaucoma?
prostaglandin analogues
Which class is most effective for lowering IOP?
prostaglandin analogues
-lower 31-33%
What should be done if a prostaglandin analogue is not tolerated or not effective?
try another within the class
Are prostaglandin analogues convenient?
yes, single drop per day
What are the side effects of prostaglandin analogues?
mild conjunctival hyperemia
thicker eyelashes
possible iris darkening (rare)
generally well-tolerated, few systemic AE
What are examples of topical beta-blockers?
betaxolol
levobunolol
timolol
What is the MOA of topical beta-blockers?
decrease production of aqueous humor
Which patients should avoid topical beta-blockers?
patients with syncope or bradycardia
Which patients should we cautiously use topical beta-blockers in?
use with caution in asthma/COPD
-avoid in severe disease
-monitor for worsening of these conditions
Which topical beta-blocker is cardioselective?
betaxolol
What is an example of a alpha-2 adrenergic agonist?
brimonidine
What is the MOA of brimonidine?
decrease production of aqueous humor and increase outflow
How is brimonidine typically used?
primarily used as adjunctive therapy
What is the con of brimonidine?
higher rate of conjunctival hyperemia and ocular allergy than prostaglandins or beta-blockers
What are examples of topical carbonic anhydrase inhibitors?
dorzolamide
brinzolamide
What is the MOA of topical carbonic anhydrase inhibitors?
inhibition of carbonic anhydrase decreases production of aqueous humor
What is the efficacy of topical carbonic anhydrase inhibitors compared to oral carbonic anhydrase inhibitors?
less effective than oral carbonic anhydrase inhibitors at decreasing IOP
How are topical carbonic anhydrase inhibitors typically used?
2nd line in people unable to use topical beta-blockers
What is an example of a topical cholinergic agonist?
pilocarpine
What is the MOA of topical cholinergic agonists?
stimulates muscarinic receptors –> constricts the ciliary muscle –> increased aqueous humor outflow
What are the adverse effects of topical cholinergic agonists?
poor tolerability
-miosis –> poor night vision
-nearsightedness
-ciliary spasms
-rare: rectal detachment
How do the different classes of eye drops compare in terms of approximate IOP reduction?
prostaglandin analogues: 31-33%
beta-blockers: 23-27%
alpha2-adrenergic agonists: 20-30%
carbonic anhydrase inhibitors: 17-21%
cholinergic agonists: 20-30%
Why are topical glaucoma medications highly concentrated?
to increase intraocular penetration
What can be done to decrease systemic absorption of glaucoma medications?
occlude the nasolacrimal drainage system or close eyes for 1-3 minutes after instilling drops
How long should you wait between administering different types of eye drops?
5 minutes
How long you should wait to apply contact lenses after instilling eye drops?
15 minutes
What is the most common preservative in eye drops?
benzalkonium chloride
-up to 6% of people are allergic
What kind of side effects can benzalkonium chloride cause?
prolonged exposure can cause superficial eye irritation –> itching, burning, irritation
may also contribute to or worsen dry eyes
What are some potential alternatives for patients allergic to benzalkonium chloride?
travaprost or brimondine have alternative preservatives
some drops are available in preservative-free, single dose units
