Angle Closure Glaucoma Flashcards
Risk factors for angle closure glaucoma
Chinese Asians more common, Eskimo’s higher prevalence compared to caucasians
- women 70%; shallow chamber, smaller axial length
- older people
- hyperopia
- smaller axial length
- fellow eyes of an individual at risk
- first degree relatives of an angle closure patient
Precipitating factors for angle closure glaucoma
Factors that produce dialtion (dim illumination, emotional stress, drugs)
Factors that produce miosis (Rare)
Primary angle closure
180 degrees or less of TM visible, IOP normal, disc normal
Secondary angle glaucoma
Secondary to systemic problem
Pupillary block and angle closure
- most common form of primary angle closure
- initiating event-increased resistance of the flow of aqueous humor at pupil and anterior surface of lens
- forward bending of iris
- closure of angle
Symptoms of angle closure glaucoma (acute)
Acura pain Nausea and vomiting Blurred vision Colored halos around lights Loss of vision
Signs of acute angle closure glaucoma
- conjunctival and ciliary congestion
- corneal edema
- shallow peripheral anteiror chamber with cells and flare
- intraocualr pressure usually exceeds 40mmHg
Signs of prior attack of angle closure
Iris atrophy
Posterior synechiae
Glaukomflecken
Structural optic nerve damage-cupping or pale nerve
Glaucomfleckin
Specific cataract to acute angle closure attack
More signs of acute closure glaucoma
- severe corneal edema
- dilated, unreactive, vertically oval pupil
- ciliary injection
- shallow anterior chamber
- complete angle slower (Shaffer grade 0)
Why do we use minimal light in gonio when checking the angle for angle closure glaucoma
Make sure you do not use bright light, because it will cause the pupil to constrict some and make the angle appear to more open than it actually is
Iris synechiae
- iris is in contact to the peripheral cornea and the TM
- during the first few hours of an acute attack snechiae
- longer the iris is against the angle, the risk of anterior synechiae formation is higher and almost certain
- once this happens, the angle will not longer open with an I ride Tony and TM outflow will be permanently affected
Causes of halos in angle closure glaucoma
Epithelium edema of the cornea
Stenopic slit and halos
◦ Slit in the trial lens
◦ Halos 360 in glaucoma
◦ Halos only in certain spots in cataracts
Corneal edema and halos
- IOP is very higher, 50mmHg or higher
- aqueous that is forced into the corneal stroma causing stretching of collagen lamellae and, eventually, epithelial edema
Mid dilated unreactive pupil in glaucoma
- paralysis and ischemia of the pupillary sphincter, caused by the increase in IOP
- causing a fixed mid dilated pupil
Cilinary and conjunctival vessels congestion
- venous congestion: this occurs when the IOP exceeds that of episcerla veins
- iris blood vessels become dilated and also the veins in the conjunctiva, given the patient a painful red eye
Iris atrophy
-the 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
Aqueous flare and acute angle closure
Mild flare due to break down of BAB so there is protein in AC
Signs of postcongestive angle closure
- folds in descemets
- stromal iris atrophy with spiral like configuration
- psoteiuror synechia
- fine pigment on iris
- fixed dilated pupil
- glauckomfleckin
Autonomic stimulation and angle closure
- nausea and vomiting may accompany the acute angle closure attack
- the oculocardiac reflex produces bradycardia (slow heart rate) and there is often profuse sweating
Sub acute angle closure
-symptoms in subacute ACG may be similar to those in acute angle closure glaucoma, but of intermittent or lower intensity, and my spontaneously disappear
Chronic angle closure glaucoma
- peripheral anteiror synechiae (PAS)
- increased IOP
- pateitn asymptomatic until vision loss
Signs of chronic angle closure glaucoma
- similar to POAG with cupping and field loss
- easily missed unless routine gonioscopy performed
- variable amount of angle closure
Combined mechanism glaucoma
- open angle and angle closure mechanisms at work
- diagnosis-IOP elevated post angel closure and successful iridotomy and open angle
Pupillary block
- eyes with shallow AC
- more anterior position of the lens
- greater anterior surface curvature of lens, increases the area of contact of the posterior iris surface to the lens
- this causes a facilitating a pressure differential between the AC and PC that causes forward bowing of the relaxed, peripheral iris
Antomical mechanism of angle closure
Lens size and position
Eyes with a thicker and anteriorly positioned lens tend to have shallower AC
Aging increases lens thickness
Mechanism of plateau iris and angle closure
- the AC depth appears to be normal
- the iris plane remains flat
- but the angle looks narrow or closed due to the shape of the peripheral iris
- iris drops abruptly in the far periphery, making a narrow recess over the TM
- th meachnisms that increase iridotrabecular contact are thicker iris, anteiror iris insertion, anterior position of the CB
The mechanisms that increase iridotrabecular contact are
Thicker iris
Anteiror iris insertion
Anterior position of the CB
Plauteau iris caution
- eyes with plateau iris configuration may have angle closure when the pupil is dilated
- iridotrabecular apposition
Plateau iris with relative pupillary block treatment
-treatment is with peripheral iridotomy
Plateau iris syndrome
- whenever gonio confirms angle closure in the presence of a patent iridotomy
- when performing indentation in these cases 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 these cases should be argon or diode laser iridoplasty
Medical treatment for angle closure
- pilocarpine
- hyperosmotic agents
- CAI
- A agonists
- Prostaglandin analogs
- BBlockers
Laser treatments for angle closure
- argona laser peripheral iridotomy
- argon laser iridoplasty
- argon laser iridotomy
- Nd:YAG iridotomy
Surgical treatment for angle closure
- AC paracentesis
- Iridectomy
- lens/cataract extraction
- filtering surgeries
- cyclodestructive surgeries
Goals of medical treatment for angle closure
- lower IOP
- alleviate pain
- clear cornea
- prevent synechiae
IV meds and ACG
- acetaxolamide 500mg IV
- IV mannitol
- best therapy is hot always available in clinic
Treatment protocol-ACG-ABC procedure
- A2 agonist-brimonidine
- BBlocker-timolol (caution in asthamatics) or betaxolol
- CAI-dorzolamide (caution sulpha allergy contraindications)
Each med given every 15 minutes
Oral meds and ACG
- oral CAI
- two tablets of 250mg acetozolamide (caution sulpha allergies contraindication)
Works good when patient can retain medication-vomitting common with ACG
How to bring IOP down in office
Give the meds suggested
- check IOP after 1 hour if lower
- add pilocarpine every 15 minutes for 45 minutes and repeat the procedure
- seek OMD opinion-refer patient
Take home meds to ACG
- prednisone acetate 1% q1-6 hours (approximately every 3 hours)
- acetaxolamide 500mg sequel BID
- AAgonist or BBlocker BID
- pilocarpine 2% QID
Indications of iridotomy
- occludalbe angle
- contralateral eye of an acute ACG
- narrow or closed angle in mroe than 180 degrees with optic nerve damage with high IOP
- acute ACG
Indications of 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 rubeosis irises
Why is IV medication the best for ACG
Acetaxolamide
Mannitol
Bypasses first pass metabolism
This will also prevent nausea and vomiting