angle closure glaucoma, OHT & NTG

risk factors of angle closure

race: Chinese asians, inuits

gender: women

age

hyperopia

smaller axial length

first degree relative

causes of secondary angle closure

Marfan's syndrome

uveitis

neovascular

what is the most common form of primary angle closure

pupillary block

what causes pupillary block

forward bending of iris increasing resistance of flow of aqueous humor at pupil & anterior surface of lens

symptoms of acute angle closure glaucoma

ocular pain

nausea & vomiting

blurred vision

colored haloes around lights

loss of vision

signs of acute angle closure glaucoma

conjunctival & ciliary congestion

corneal edema

shallow peripheral anterior chamber with cells & flare

IOP > 40 mm HG

signs of prior attack of angle closure

iris atrophy

posterior synechiae

glaukomflecken

structural optic nerve damage: cupping or pale nerve

what happens if iris is against the angle for a long time

the angle will no longer open with iridectomy & trabecular outflow will be permanently affected

characteristics of corneal edema

IOP > 50 mm Hg

aqueous is forced into stroma causing stretching of collagen lamellae & epithelial edema

what is the cause of fixed mid dilated pupil

paralysis & ischemia of the pupillary sphincter caused by increase in IOP

when does venous congestion occur

when IOP exceeds that of episcleral veins

what causes the painful red eye in those with angle closure

iris & conjunctiva blood vessels become dilated

what causes iris atrophy

abrupt increase in IOP causes an interruption of the arterial supply to the iris resulting in ischemia which causes damage to the iris leaving behind patches of stromal atrophy

what causes aqueous flare

mild flare due to break down of blood aqueous barrier so there is protein in anterior chamber

what autonomic stimulation does angle closure glaucoma cause

nausea & vomiting

oculocardiac reflex produces bradycardia & profuse sweating

symptoms of subacute angle closure

similar to ACG but intermittent or lower intensity & may spontaneously disappear

signs of chronic angle closure glaucoma

peripheral anterior synechiae

increased IOP

cupping & vision field loss

asymptomatic until vision loss

predisposing factors of pupillary block

eyes with shallow anterior chamber

more anterior position of lens

greater anterior curvature of lens

eyes with thicker lens (aging increases thickness)

pupillary block mechanism of action

the greater area of contact of the lens with iris surface causes a pressure differential between the anterior & posterior chambers that causes forward bowing of the relaxed peripheral iris

what does plateau iris look like

anterior chamber depth appears to be normal, the iris plane remains flat but the angel looks narrow or closed because the iris drops abruptly in the far periphery making a narrow recess over the TM

what are the mechanisms that increase iridotrabecular contact

thicker iris

anterior iris insertion

anterior position of ciliary body

plateau iris caution

may have angle closure when pupil is dilated

how to treat plateau iris with relative pupillary block

peripheral iridotomy

what is plateau iris syndrome

whenever gonioscopy confirms angle closure in the presence of a peripheral iridotomy

when happens when performing indentation in plateau iris syndrome

the iris can be pushed posteriorly so it assumes a concave shape that follows the lens curvature but the peripheral iris remains elevated due to the position of the ciliary processes

treatment for plateau iris syndrome

argon or diode laser iridoplasty

what is the best medications for angle closure glaucoma but not the most practical?

IV meds

intravenous meds for angle closure glaucoma

acetazolamide 500 mg

mannitol

what is the ABC procedure of acute angle closure glaucoma

alpha 2 agonists: brimonidine

beta blocker: timolol or betaxolol

carbonic anhydrase inhibitor: dorzolamide

each med every 15 mins (3x)

contraindications of carbonic anhydrase inhibitors

sulfa allergy

oral meds for angle closure glaucoma

oral acetozolamide 250 mg 2 tablets

what are the take home meds for angle closure glaucoma

prednisolone acetate q1-6hrs

acetazolamide 500 mg BID

alpha agonists or beta blockers BID

pilocarpine QID

what is the order of medical therapy for angle closure glaucoma

1. ABC x3 + oral acetazolamide

2. check IOP after 1 hr

3. if <40: ABC x3 + pilo then when IOP is in 20s take home meds

4. if >40: ABC x3 then once <40 do step 3

treatment order for someone with open angle but high IOP

1. ABC x3 + oral acetazolamide

2. once IOP is in 20s send home with CAI, brimonidine

3. if there is inflammation give steroids

indications for iridotomy

occludable angle

contralateral eye of an acute ACG

narrow or closed angle in more than 180 degs with optic nerve damage & high IOP

acute ACG

indications for peripheral iridoplasty

plateau iris

in preparation for laser trabeculoplasty

after iridotomy if iris apposition is still present

before an iridotomy in cases of thick, inflamed or rubeotic irises

what was the conclusion of the ZAP trial

prophylactic LPI for angle closure suspects was not recommended

what is conclusion of the EAGLE trial

clear lens extraction after primary angle closure glaucoma showed greater efficacy & more cost effective than LPI

what is STAR II calculator

assesses risk and should only be used in untreated OHT patients

prevalence of ocular hypertension (OHT) in caucasians?

around 4%

what is the number of OHT treated patients needed to treat for only 1 person to not progress into glaucoma

20

what glaucoma does the Japanese population have a higher prevalence of?

normal tension glaucoma

clinical features of NTG

- damage present despite lower than statistically normal pressures

- higher prevalence of Raynaud phenomena, ischemia vascular disease, autoimmune disorder & coagulopathies

- progressive disorder

VF loss in NTG

progression is slow

defects focal, deeper & central

what could be the initial VF defect in NTG

dense paracentral scotoma encroaching on fixation

optic disc characteristics of those with NTG

thinner rim interiorly & inferiotemporally when compared to other glaucoma with similar total VF loss

senile sclerotic group

focal ischemic

what is a senile sclerotic group

shallow, sloping of NRR

what does focal ischemia look like

deep focal polar notching in the neuroretinal rim

what evaluations should you do if you have an atypical case where structure & function don't relate

neurological evaluation

1. auscultation & palpation of the carotid arteries

2. focus on blood flow

3. post chiasma investigation using CT & MRI