Management of Primary Angle Closure Glaucoma

Primary angle closure is due to:

an anatomical predisposition

Secondary angle closure is due to:

a pathological process

A non-pupil block angle closure has which iris configuration

plateau iris

A pupil block angle closure has which iris configuration

iris bombe

Which 2 additional tests are performed on an acute angle closure pt along with ocular hx and comprehensive exam

- gonio

- UBM or AS-OCT

(T/F) Acute Primary Angle Closure is a severe threat to vision

TRUE

extremely elevated IOP leads to rapid and permanent blindness if not properly treated

(T/F) An acute angle closure attack is an ocular emergency

TRUE

(T/F) The longer the duration of an angle closure attack, the greater the damage to ocular structures

TRUE

List the 5 sx of Acute Angle Closure Glaucoma

• Pain

• Halos

• Visual loss

• Nausea

• Vomiting

Go read the clinical signs of Acute Angle Closure Glaucoma on slide 5 & 6

SOME KEY ONES:

• Intraocular pressure from 40-80mmHg

• Mid-dilated, unreactive pupil

• Ischemic iris

• Ciliary-conjunctival injection (ciliary flush)

• Corneal edema

• Cells in aqueous (but no keratic precipitates)

• Posterior synechiae

• Glaukomflecken

What is the first step after dx a pt with acute angle closure

initial medical treatment is started immediately upon diagnosis

- can refer to ER but you must begin to attempt to lower the pressures right away

How does the high IOP in acute angle closure impact the responsiveness to Pilocarpine

Pilocarpine is used to lower IOP by constricting the pupil and pulling the iris out of the angle to physically open it

when the IOP is so high it cuts off the blood supply to the iris, the iris will not receive any of the drug and therefore will not have the constriction response

What are the limitations with corneal haze that occurs in acute angle closure

corneal haze blocks your view into the eye... you are unable to view the angle through gonio and laser procedures cannot be performed when the angle cannot be visualized

(T/F) Lowering the IOP signifies that the angle closure attack is broken

FALSE

opening of the angle signifies that the attack is broke

What are the 2 definitive tx options for acute angle closure glaucoma

- laser

- incisional surgery

opening the angle short-term breaks the attack but this is not a definitive tx

Miotic drops are ineffective when IOP is higher than ____mmHg

higher than 40mmHg

List the 5 classes of drugs used to initially treat Acute Angle Closure Glaucoma (in the order that they would be used)

- CAIs (oral or IV)

- b-blockers (topical)

- a-agonists (topical)

- miotics (topical)

- osmotic agents (oral)

Why are PGAs not used in initial Acute Angle Closure tx

PGAs function by increasing outflow

but the angle is closed so outflow cannot be increased

we instead use the ABCs because they all decrease production

What is the mechanism of action of the CAIs for glaucoma tx

IOP-lowering effect is due to its reduction of aqueous production

What is the mechanism of action of the beta-blockers for glaucoma tx

IOP-lowering effect is due to its reduction of aqueous production

What is the mechanism of action of the alpha-agonists for glaucoma tx

IOP-lowering effect is due to its reduction of aqueous production

What is the mechanism of action of the miotics for glaucoma tx

parasympatholytic alkaloid acts on muscarinic receptors found on iris sphincter muscle → causes muscle to contract → miosis → pulls iris away from trabecular network

Which CAI is most widely selected for the emergency treatment ofangle-closure glaucoma

Acetazolamide

Give the oral dosage of Acetazolamide as an acute angle closure drug

2 x 250mg oral

additional full doses can be given 4 to 6 hours later to lower the IOP

Give the topical dosage of Prednisolone acetate as an acute angle closure drug

1% 1gtt q15-30 minutes 4x then q1h

Give the oral dosage of Glycerin as an acute angle closure drug

1-1.5g/kg of body weight of a 50% solution

Give the oral dosage of Mannitol as an acute angle closure drug

1 to 2 g/kg of body weight of a 50% solution

Give the IV dosage of Mannitol as an acute angle closure drug

2 g/kg of body weight of a 20% solution over 30 minutes

Which oral osmotic agent needs to be avoided in DM pt

Glycerin

Glycerin causes its max decrease in IOP ___-___ (min/hrs) after administration and may remain low for the following ___-___ (min/hrs)

30 to 90 minutes

5 to 6 hours

Mannitol causes its max decrease in IOP ___-___ (min/hrs) after administration and may remain low for the following ___-___ (min/hrs)

1 to 3 hours

3 to 5 hours

List the 3 contraindications of Glycerin

- DM pt

- elderly w renal failure

- elderly w cardiovascular disease

Which oral osmotic agent is safe to use in DM pt

Mannitol / Isosorbide

Give the IV dosage of Acetazolamide as an acute angle closure drug

500-mg bolus

additional full doses can be given 4 to 6 hours later to lower the IOP

_____________ is a topical CAI sometimes used in acute angle closure, but is less effective than oral/IV Acetazolamide

Dorzolamide (Trusopt) 2%

_____________ is a topical alpha agonist sometimes used in acute angle closure, but is less effective than topical Apraclonidine

Brimonidine 0.2%

Give the topical dosage of Timolol as an acute angle closure drug

0.5% Timolol administered twice at a 30-minute interval as part of the initial treatment

drop may be repeated 4, 8, and 12 hours later

Give the topical dosage of Pilocarpine as an acute angle closure drug

2% or 4% Pilocarpine every 15 minutes for four doses, then after 1 to 2 hours, every 30 minutes

Timolol reaches a high concentration and activity in the posterior chamber ____-____ minutes after topical application

30 to 60 minutes

Timolol reduces IOP by around ____-____% within 1 hour of instillation

20% to 30%

What is the name and % of the Alpha Agonist most commonly used in angle-closure glaucoma in conjunction with other medical therapy

Apraclonidine (Iopidine) 1%

Apraclonidine reduces IOP by around ___% within 2 hours after topical application

26%

Apraclonidine reduces IOP by around ___% within 5 hours after topical application

34%

Pilocarpine likely does not work until IOP drops below ___-___ mmHg, but can still give immediately upon diagnosis

40-50 mmHg

Pilocarpine is ineffective in an attack longer than ___-___ hours

1 or 2 hours

If the etiology of the angle closure is pupil block, which class of drug should be avoided and why

miotics

the mechanism of these drugs is to constrict the pupil, this action may cause more pupil block and lead to an increase in IOP rather than a decrease

(T/F) Topical steroid are used during an acute angle closure attack

FALSE

very important to not use steroids during an acute angle closure attack because it will make it worse

used as tx to help inflammation AFTER!!! IOP under control

Why are topical CAIs not included in the acute angle closure tx regmine

tend to aggravate corneal edema, making the corneal haze even worse

Why are topical PGAs not included in the acute angle closure tx regmine

they have no effect unless the angle is at least partially oopen

technically could still be used and have some benefit if the pt isnot experiencing 100% angle closure, however the lowering effect will not be as good as you would expect in a regular pt

(T/F) In the case of an acute angle closure, a strong miotic should be used for best miotic IOP lowering effect

FALSE

stronger miotics show no advantage over low dose

(4% vs 1% pilocarpine have the same effect)

Brimonidine has neuroprotective properties but is not the first alpha-agonist of choice when it comes to acute angle closure tx.... why

because Aproclonidine has a stronger lowering effect

AND

the neuroprotective properties have only been proved in long term, chronic therapy... not short term acute use

Give the 4 steps of a sample ER acute angle closure medical protocol in order of importance

- lower IOP

- alleviate inflammation

- reduce pain

- reduce nausea

(read slide 18 for full protocol)

(T/F) Once intraocular pressure lowering or miosis of the pupil is achieved, topical medical therapy can be stopped

FALSE

topical medical therapy should be continued until definitive surgical treatment is performed or reopening of the angle is assured

How is gonioscopy used off label as a method of IOP lowering

indentation gonioscopy, by pushing the central aqueous to the periphery, may open an appositionally closed angle

Indentation gonioscopy would not work as temporary angle closure relieve in eyes when the reason for the angle closure is due to _______

PAS

(T/F) Indentation gonioscopy may be tried as a therapeutic means to break an angle-closure attack and the pt will not longer need surgical therapy

FALSE

even if successful in reopening the angle, indentation gonioscopydoes not replace the use of definitive treatment: peripheraliridotomy

Give the full drug list and dosage that makes up a suggested regimen for an angle closure kit kept in office

• Acetazolamide 500 mg po initially (IV if patients are nauseated)followed by 250 mg q 6 h

• Timolol 0.5% one drop q 30 min for 2 doses

• Apraclonidine 0.5 to 1% one drop q 30 min for 2 doses

• Pilocarpine 2 to 4% on drop q15 min for the first 1 to 2 hours

The suggested regimen of drugs in the angle closure kit is not effective at IOP >___mmHg

>40mmHg

(T/F) Regardless of the appearance of the angle on gonioscopy, all eyes that have suffered a primary acute angle-closure attack should have LPI or iridoplasty

TRUE

List 2 possible side effects of systemic medications used to releive acute angle closure attacks

• Metabolic acidosis

• Electrolyte disturbance

What is Anterior Chamber Paracentesis

surgical treatment option (NOT PERFORMED BY ODs) that involves poking the cornea and physically release some aqueous from the anterior chamber

______________ is considered the definitive treatment of acute PAC with pupil block

Laser Peripheral Iridotomy

When is Surgical Iridectomy indicated as acute PAC tx

indicated only when laser treatment can not be accomplished

(laser/surgical) tx of acute PAC is much safer, why

laser is much safer

opening the globe for a surgicaliridectomy in a patient with high IOP greatly increases the riskof suprachoroidal hemorrhage

Why do surgeons typically avoid the 12 o'clock position for Laser Peripheral Iridotomy aperture

in case gas bubble forms from procedure and floats superior and blocks aperture

Why do surgeons commonly avoid the 1 & 11 o'clock position for Laser Peripheral Iridotomy aperture

more intense optical aberrations due to tear prism at lid margin causes base-up prism optical effect

The iridotomy site should be in the peripheral 1/__ of the iris just (anterior/posterior) to any arcus

peripheral 1/3rd

just anterior to any arcus

Why is a crypt or a thinned area of the iris is recommended for iridotomy location

there is less tissue to have to burn through in these areas and the we want to use the lowest amount of energy on the laser to decrease adverse effects

Fellow eye has a ___-___% chance of developing an acute attack within 5-10 years

40-80%

(T/F) A prompt prophylactic LPI is recommended in the contralateral eye when one eye has had an acute PAC

TRUE

fellow eye has a 40-80% chance of developing an acute attack within 5-10 years

Laser Peripheral Iridoplasty (gonioplasty) is typically used for which iris configuration

plateau iris

Describe the mechanism of how gonioplasty worse

• series of laser burns perpendicular to the extreme peripheral iris

• scars over and physically contracts the iris stroma

• tightening of the peripheral iris mechanically creates space between the anterior iris surface and the TM

• Iris contracture and flattening of the surrounding iris pulls the iris away from the cornea.

IOP usually lowers how long performing a Laser Peripheral IridoPLASTY procedure

within 1 hr

(T/F) An acute attack can be broken with Iridoplasty alone, without medication

TRUE

(T/F) Recent study showed anti-glaucoma medications are safer and more effective than Gonioplasty

FALSE

gonioplasty safer and more effective

(T/F) Iridoplasty breaks acute PAC attack and is used as a definitive tx

FALSE

Iridoplasty only breaks the attack and does NOT fixpupillary block

laser peripheral iriDOTomy should be performed subsequently as the definitive treatment

_____________ is the most appropriate long-lasting therapy for subacute (intermittent) angle-closure glaucoma

laser iridotomy

List the 3 subacute (intermittent) angle-closure glaucoma tx methods in order of which should be attempted first

-iridotomy

- iridoplasty

- filtration surgery

Give 3 complications risks that com with laser iridotomy

• cataract formation

• post operative corneal or lenticular burns

• progressive corneal edema

Tx with LPI does not always prevent closure.... 1/___ STILL have appositional angle closure due to another pathologic mechanism going on

1/5

According to studies, ___% of PAC suspects progress into acute angle closure

3-6%

According to studies, ___% of PAC suspects progress into chronic angle closure

13%

Eyes with extensive PAS respond (well/poorly) to LPI, why

poorly

unlikely LPI will break longstanding PAS

Laser iridotomy is only indicated in eyes with:

appositional closure

_____________ is the first step in the treatment of chronic primary angle-closure glaucoma

laser iridotomy

(unless due to PAS)

(T/F) Plateau iris will persistent with appositional closure despite a patent iridotomy

TRUE

(iridotomy/iridoplasty) is the best option for a pt with plateau iris

iridoplasty

(iridotomy/iridoplasty) is the best option for a pt with chronic angle closure

iridotomy

(iridotomy/iridoplasty) is the best option for a pt with intermittent angle closure

iridotomy

(iridotomy/iridoplasty) is the best option for a pt with acute angle closure

iridotomy

List the 3 beneficial effects Gonioplasty has on a plateau

• flattens the plateau iris configuration

• opens the appositionally closed angle

• there is good long-term effectiveness

List the 2 ways lens extraction helps prevent angle closure

- decreases risk of pupillary block

- deceases crowding of the anterior chamber

The (narrower/wider) the preoperative angle, the greater the postoperative widening

narrower

(has more potential of opening the more closed off it starts)

Lens extraction is the definitive tx for which type of glaucoma

phacomorphic glaucoma

Give the name and results of the EAGLE study

Effectiveness in Angle-Closure Glaucoma of Lens Extraction

results:

tested clear lens extraction vs laser peripheraliridotomy for first-line treatment of PACG and PAC

found better IOP lowering, more cost effective and greater quality of life in lens extraction group

this could shift the current standard first line tx from meds and laser but has not reached that point yet

Up to ____% of patients with acute PAC have persistent IOP elevation requiring glaucoma medications following laser iridotomy

60%

Post-operative IOP control depends on which 2 things

• Amount of TM damage

• Extent of PAS

(T/F) Irreversible damage to the TM will occur if the PAS remains untreated

TRUE

logical approach is to eliminate the PAS and restore normal TM function

Goniosynechialysis (GSL) is an effective procedure designed to:

strip the PAS from the angle wall and restore trabecular outflow

Goniosynechialysis is ____% effective in eyes with PAS for.. how long

80% effective

<1year