PBL 1 Flashcards
what is glaucoma?
a group of eye diseases caused by intraocular hypertension which can damage the optic nerve and, if left untreated, can lead to blindness
at what age is glaucoma most common?
between 70s and 80s
what is considred a high intraocular pressure?
> 21mmHg
what are the 2 causes of increased intraocular pressure?
blocking of the aqueous humor drainage pathway or an increased aqueous humor production
what are symptoms of glaucoma?
peripheral vision loss
blurred vision
seeing rainbow coloured circles around bright lights
what are risk factors for glaucoma?
raised intraocular pressure being >60 family history being black, asian or hispanic corticosteroid use myopia (short sightedness) type 2 diabetes hypertension CVD
how is glaucoma diagnosed?
tonometry - assess intraocular pressure
visual field testing
imaging or directly observing for optic nerve damage (often see cupping of the optic nerve)
why do we often see cupping of the optic nerve in glaucoma?
as we get thinning of the outer rim of the nerve, givving it a cup shape
what are the 5 types of glaucoma?
open angle closed angle normal tension secondary congenital
what is congenital glaucoma?
a developmental glaucoma occurring before the age of three years due to an obstruction that prevents adequate drainage of aqueous humor caused by abnormal development of the trabecular meshwork (TM) and anterior chamber angle
what are some underlying eye conditions that can cause secondary glaucoma?
steroid use, eye injury, uveitis
what is normal tension glaucoma?
a form of glaucoma in which damage occurs to the optic nerve without eye pressure exceeding the normal range.
what is considered a normal pressure rnage for intraocular pressure?
12-22 mmHg
what is open angle glaucoma?
when the angle of the anterior chamber is open but the drainage system slowly becomes clogged over time so we get a gradual increase in intraocular pressure and therefore gradual damage to the optic nerve. This begins as atrophy of the outer rim of the nerve causing a decrease in peripheral vision but as pressre increases we get continued damage which eventually will lead to a loss of central vision too
what is closed angle glaucoma?
when the angle of the anterior chamber is too small so the aqueous humor outflow path is too narrow which leads to a rapid build up of pressure in the eye which can cause an abrupt onset of symptoms
what are symptoms of closed angle glaucoma?
abrupt onset of…
severe eye pain, eye redness, blurry vision, headaches, nausea, visual haloes, vision loss
outline the role of the autonomic nervous system on the intraocular pressure?
the parasympathetic system causes pupillary constriction, decreasing intraocular pressure
sympathetic system causes pupillary dilation which increases intraocular pressure
what are the 3 main treatment options for glaucoma?
topical prostaglandin analogues
topical beta blockers
carbonic anhydrase inhibitors
what are the 3 main treatment options for glaucoma?
topical prostaglandin analogues
topical beta blockers
carbonic anhydrase inhibitors h
what are the 3 main treatment options for glaucoma?
topical prostaglandin analogues
topical beta blockers
carbonic anhydrase inhibitors h
how do prostaglandin analogues work to treat glaucoma?
they increase the outflow of aqueous humor, decreasing intraocular pressure
what are side effects of topical prostaglandin analogues?
burning in eyes
darkening of eyelids
blurred vision
how do topical beta blockers work to treat glaucoma?
they decrease aqueous humor production by blocking adneylyl cyclase
how do carbonic anhydrase inhibitors work to treat glaucoma?
inhibiting CA causes decreases HCO3- production which leads to a decreased aqueous humor production
what are examples of topic prostaglandin analogues used in glaucoma?
latanoprost
travoprost
bimatoprost
tafluprost
what are examples of topical beta blockers used in glaucoma?
betaxolol
levobunolol
hydrochloride
timolol maleate
what are examples of carbonic anhydrase inhibitors used to treat glaucoma?
brinzolamide and dorzolamide
what are side effects of topical beta blockers?
hypotension
difficulty breathing
bradycardia
what are side effects of carbonic anhdrase inhibitors?
burning in eyes
metallic taste
increased urination
what are some non-medication treatment options for glaucoma?
laser treatments e.g. trabeculoplasty, iridotomy, destroying humor-producing cells, creating a new aqueous humor exit route
implants to shunt fluid from anterior chamber bypassing trabecular meshwork ans collecting system
what is a trabeculoplasty?
laser surgery that opens trabecular mesh netwrok
what is an iridotomy?
laser treatment that punches a small hole in the iris
what laser treatment is used to treat open angle glaucoma?
trabeculoplasty
what laser treatment is used to treat closed angle glaucoma
iridotomy
