Angle-Closure Glaucoma Flashcards
What percentage of bilateral blindness in China is attributed to angle closure glaucoma?
91%
What percentage of presentation is acute/abrupt? Chronic and insidious?
20-30% of cases present acutely
70-80% of causes are asymptotic and insidious
What are the two varieties of angle closure glaucoma?
Primary= anatomical predisposition to angle closure Secondary= an identifiable anatomic cause that initiates the angle closure
What is the hallmark physical exam finding in angle closure glaucoma?
apposition or adhesion of the peripheral iris to the TM (either via rear push or forward pull mechanism)
What is the most common cause of angle closure glaucoma?
Pupillary block
What is pupillary block? When is angle closure maximum?
obstruction of the lens-iris interface that causes a pressure gradient b/w the PC and AC, which in turn causes the peripheral iris to bow anteriorly
angle closure is maximized when the pupil is mid-dilated
What is the leading cause of glaucoma worldwide?
angle closure
What is a general characteristic of eyes that are more susceptible to angle closure?
Hypertropic eyes, or eyes with axial length < 20 mm, are at increased risk for PACG
How does most angle closure present?
asymptomatic chronic disease without an acute attack
usually bilateral
If angle closure presents unilaterally, what other causes should be considered in the differential diagnosis?
- posterior segment mass
- zonular insufficiency
- ICE syndrome
What are RFs for angle closure?
- shallow AC (<2.5 mm)
- increased anterior curvature of lens
- short axial length
- small k diameter and radius of curvature
How does angle closure relate to age?
prevalence of angle closure increases each decade after age 40 2/2 increased thickness of lens and forward movement of iris, causing increased iridolenticular contact
Is there a gender prevalence for angle closure?
Woman are 2-4x more likely to suffer from angle closure 2/2 smaller AC and AC angle
If a myopic patient presents with angle closure, what should be considered as a part of the Ddx?
- microspherophakia
- plateau iris
- phacomorphic closure
What are s/sx of angle closure?
- increased IOP
- blurred vision/decreased central VA
- rainbow colored halos around lights
- n/v
- ocular pain
- shallow ac
- mild AC reaction (cell and flare)
How do you distinguish between appositional and synechial angle closure via physical exam?
Dynamic gonioscopy
If appositional, blockage will be reversible
If synechial, not reversible
Why do patients with angle closure present with blurred vision/visual symptoms?
K endothelial edema
What are glaucomflecken?
characteristic small anterior sub capsular lens opacities 2/2 ischemia
What is the definitive treatment of angle closure?
B/L LPI, or less commonly, surgical iridectomy
mild attacks may be broken with miotics (2/2 pulling peripheral iris away from TM)
How do mitotic agents work to decrease IOP?
They decrease IOP in angle closure by pulling peripheral iris away from TM
If an LPI cannot be performed, how can an attack of acute angle closure be broken?
laser iridoplasty (flattens peripheral iris) or laser pupilloplasty
What is subacute/intermittent angle closure?
characterized by episodes of blurred vision, halos, and mild pain 2/2 increased IOP
Often resolves spontaneously
sx more common at night
What is chronic angle closure?
gradual asymptomatic closure, which is the most common form
How is chronic angle closure managed?
LPI (unless significant lens opacity is present; then perform lensectomy)
if synechial angle closure: goniosynechiolysis
Why do chronic angle closure and POAG need to be considered in the differential diagnosis for patients presenting with increased IOP?
They both need to be considered b/c they usually are both asymptomatic, or present with initial modest IOP increase, progressive glaucomatous ON damage, and characteristic VF loss
What are the indications to perform an iridotomy?
- narrow angle with appositional/near appositional angle closure
- PAS
- increased TM pigmentation
- Hx of previous angle closure
- (+) provacative test results (>8 mm Hg increase in IOP)
- significant risk of angle closure (AC depth < 2mm, strong FamHx)
What is plateau Iris?
atypical configuration of the AC angle that may cause ACG; typically in young females
usually 2/2 anteriorly positioned ciliary processes that push the iris forward
What is the characteristic sign of plateau iris on ultrasound?
“Double Hump” sign
What is the treatment for plateau iris?
LPI (to remove pupillary block)
lensectomy (if cataract present)
How do plateau iris configuration and plateau iris syndrome differ?
plateau iris configuration may be treated with LPI
Plateau Iris Syndrome will not respond to LPI, needs to be treated with laser iridoplasty
What is phacomorphic glaucoma?
pathological narrowing of the angle related to acquired mass effect of cataractous lens itself
generally occurs slowly with formation of the cataract
What is the treatment for phacomorphic glaucoma?
Laser iridotomy followed by CE (in most cases, CE is definitive treatment)