Glaucoma Flashcards
- glaucoma
- define (1)
- what is normal intraocular pressure
- the pathological rise in intraocular pressure sufficient enough to damage vision
- normal is below 21mmHg. most pts have around 16
-types of glaucoma
- primary open angle glaucoma most common
- normal pressure glaucoma - similar to primary open angle but press within normal limits. similar mx
- acute angle closure glaucoma less common, makes up 5%
- secondary glaucoma do not need to know details - can be due to vascular disease, uveitis, trauma, tumours, iatrogenic
- congenital glaucoma
primary open angle glaucoma
-aetiology/risk factors -background (2) pmh(2) fh (1)
Myopia = short-sightedness
Hypermetropia = long-sightedness
aetilogy/risk factors
>bg- older age, african desent. pmh - diabetes, high myopia, diabetes, Fuch’s corneal endothelial dystrophym, retinitis pigmentosa. fh - glaucoma
primary open angle glaucoma
- sx (1) signs (3) course
- bilateral or unilateral. course untreated (2) treated(1)
- most pts do not notice visual field changes
- signs - riased introccular pressure, cupping of optic disc, visual field loss
- nearly always bilateral but disease often begins in one eye
- in untreated pt chronically raised pressure leads to progressive damage to optic nerve and eventual blindness.
- can be arrested by treatment
primary open angle - stages in pathophysiology(4)
-pathophysiology
>inadequate drainage of aqueous humour
>increased intraoccular pressure
>causes impaired circulation of optic disc
>nn fibre become ischaemic and atrophied
primary open angle - optic disc cupping
- stages of optic cupping (2)
- the bend in the blood vessels corresponds to what (1)
- image shows cupping of optic disc*
-stages of optic cupping. see image (top one is normal disc)
>cup becomes enlarged with long axis arranged vertically
>notching of the neuroretinal rim of optic disc esp in inferotemporal and superotemporal regions common
-the bend in the blood vessels correspond to the edge of the optic disc cup
-in some eyes the area of pallor can correspond to cup, in others the cup is larger than area of pallor
prim open angle - vis field loss
- what is location of physiological blind spot
- pt with early glaucoma has what sort of visual field loss
- if untreated how canthis progress
- location of blind spot - about ten degrees lateral and slightly below level of fixation
- pt with early glaucoma has what visual field loss extending in arcuate manner above and below fixation. this is because early cupping is superior and inferior as mentioned before. eg superior arcuate scotoma see image (scotoma = an area of vis field loss)
- if untreated scotoma extends around periphery of visual field and centrally
prim open angle glaucoma
- topical glaucoma medications (5) applied as drops
- surgery is an option in treatment resistance (2)
- prostaglandins - first line
- beta blockers -second line
- cholinergics
^in practice used in combination
-carbonic anhydrase inhibitors useful adjunct
-adrenergic agonists can supplement in
-poss surgeries inc trabeculectomy and laser treatment
prim open angle - mx
- prostaglandins. eg (1) moa (1) se(2)
- bblockers eg(4) moa(1) se(3) ci in pts(5)
- cholinergics/miotics. eg(2) moa(1) pilocarpinese(4)
- miosis = constriction*
- Mydriasis = dilation*
- prostaglandins. eg latanoprost . moa increased aqueous humour drainage. se slight conjunctivial congestion (hyperaemia), increased iris pigmentation in some pts
- bblockers. eg timolol, betaxolol, levubunolol, carteolol . moa reduce aqueous production . se bronchospasm, reduce cardiac contractility, bradycardia . ci in asthma, copd, heart block, bradycardia, low bp
-cholinergics eg pilocarpine (a parasymathomimetic), phospholine iodide (an anticholinesterase). moa increase drainage. pilocarpine se small pupil, dimming vision, aching over brow, blurred vision.
prim open angle - mx
adrenergic agonists. eg(2) moa (1) se(3)
carbonic anhydrase inhibitors eg (2) moa (1)
- adrenergic agonists. eg adrenaline and prodrug, brimonidine (this one is a2 selective so does not have resp se). moa decrease production of aqueous humour. se chronic dilation of conjunctivial vessle,s deposition of pigment in conjunctivia, subconjunctivial fibrosis.
- carbonic anhydrase inhibitors eg dorzolamide, acetazolamide (this one is the only mx given orally se inc paresthesia of hands and feet, gastic upset, lethargy). moa reduce aqueous production
acute angle closure glaucoma
-aetiology/risk (2)
nb Myopia = short-sightedness
and Hypermetropia = long-sightedness
-younger age group, predisposed due to eye shape (shallow anterior chamber and hypermetropia)
acute angle closure
-pathophysiology(4)
-pathophysiology
>shallow ant chamber and hypermetropia predispose
>lens grows gradually with age contributing to risk
>dilating pupil can precipitate attck
>raised intraoccular pressure occurs due to occlusion of angle
acute angle glaucoma - sx
subacute attacks easily missed
pcs(2). macrotiming (1). exac(1) relievers(1) assx(1)
acute attacks site threatening if untreated
pcs (3) assx (3) pmh (1)
subacute attack
-pcs - pain over eye, blurred vision due to cornea becoming oedematous. macro timing - may have several attacks and go undiagnosed. exac - acute rise in pressure triggered by dilation of pupil eg at night relievers - relieved by constriction eg on going to bed assx - headache
acute attack
-pcs - eye pain, red eye, severely blurred vision. assx headace, sometimes nausea and vomitting. pmh subacute attacks in past
acute angle closure glaucoma - signs (6)
- corneal oedema resulting in poor visual acuity
- shallw anterior chamber
- ciliary injection resulting in red eye
- semidilated oval pupil caused by iris ischaemia
- tenderness of globe
- hard eye
acute angl glaucoma - mx(4)
emergency. sooner treated better result. can be site threatening
-on admission to control pressure
>intensive miotic drops eg pilocarpine every 5 min
>acetazolamide iv then oral
-then surgery this is cure
>irodotomy or irodectomy
-then prophylaxis for other eye
