Laser Therapy For Angle Closure Glaucomas Flashcards
Indication for LPI
Any form of angle closure glaucoma that has pupillary block as a component
Pupillary block
Restriction of aqueous flow format the posterior chamber to the anterior chamber as it moves between the posterior surface of the iris and the anterior surface of the lens
Iris bombe: bowing forward of the iris
Relative pupillary block
Functional, or partial restriction of flow
Most common mechanism
Absolute pupillary block
Posterior synechiae completely binds down itis
LPI indications
AACG Malignant glaucoma Pigment dispersion syndrome and glaucoma Phacomorphic glaucoma Eyes with occludable angles
Acute angle glaucoma
Urgent but uncommon dramatic symptatomic event with blurring of vision, painful red eye, headache, nausea, vomitting. Diagnosis is made by noting high IOP, corneal edema, shallow anterior chamber, and a closed angle on gonio. Medical or surgical therapy is directed at widening the angle and preventing further angle closure. If glaucoma has developed, it is treated with therapies to lower IOP
History and exam for AACG
Key factors for AACG
- presence of risk factors (hyperopia, thick cataractous lens)
- Halos around lights
- aching eye or brow pain
- HA
- nausea, vomitting
- reduced VA
- eye redness
- closed angle on gonio
- extremely elevated IOP
- corneal edema
- engorged conjunctival vessels
- fixed dilated pupil
What do we do in office to treat AACG
Put whatever OHTN drops you have in their eye and get the pressure below 40, put pilo in and do an LPI
Narrow angles and occludable angles
Narrow angles are just arrow
- may watch and consider other risk factors for the development of glaucoma
- intermittent IOP spikes
- intermittent eye pain
Narrow angle glaucoma
-indication for LPI
Malignant glaucoma
After any type of surgery for angle closure glaucoma, it is possible for the anterior chamber to become shallow OT flattened and for the IOP to become elevated. Aqueous humor flow can be forced backward into the vitreous by ciliary body apposition to the lens and/or vitreous
Occludable angle
Less than 20%=probable
Less than 10%=likely
Definitive treatment for malignant glaucoma
Vitrectomy
Difference between iris bombe and malignant glaucoma
The lens is being shoved forward in malignant glaucoma
Malignant glaucoma and LPI
Unsuccessful in treatment, although is useful if differentiating from pupillary books
-ant seg OCT very valuable
What’s the difference between PI configuration and syndrome
IOP
Configuration: anatomical anomaly but not causing pupillary block commenting causing increased IOP
If it doesnt cause IOP spike its sybdrome
Both have anteirorly placed CB
Plateau iris
Double hump on indentation gonioscopy
LPI in pigmentary dispersion syndrome
LPI: iris is bowed backwards and rubbing pigment. The fluid coming from the posterior cant get to the angle in bombe, but the physics are the same here. You equalize the pressure between the anterior and posterior and you get the iris to flatten, this decreases the amount of rubbing on the lens, which decreases the amount of pigment and decreases the stopping up of the TM, which decreases IOP
This only works if their iris is concave. There are some people that don’t have concave iris. These people would not benefit from an LPI.
When is LPI indicated for PDS
If they have concavity on iris
Spaeth
Complicated system involving he location of the insertion of the iris, the angle it formes with schwalbes line. The iris configuration, and pigment level
Importance of ant segment OCY
CYA when you do a LPI
Work up of peripheral iridotomy
Comprehensive exam, diagnosis, DFE
Pre op for LPI
- VA< IOP, Med/allergy check, vitals
- brimonidine, iopidine
- pilo
- informed consent
Vitals before a LPI
BP, temp, pulse, oximetry
If you do a procedure without informed consent
It’s considered assault and battery
Lens for LPI
Abraham
-66D
Can also use Wise
- 103D
- easy to get lost
Why use a lens on LPI
- magnifies iris with good depth of field
- concentrates laser energy
- speculum
- heat sink to minimize corneal damage
- control the eye
- focus energy of laser, less to retina (increases cone angle)
Lasers for LPI
Nd:YAG
-3-6mL
Argon (or green diode)
-600mW
Thermal YAG
Argon, green diode
- reduces risk of bleeding
- may require more energy
LPI with a YAG
-generally most accepted method, especially light eyes
LPI, thermal or YAG?
Some advocate pre treat with thermal, esp dark irides and then finish with YAG
Treatment location for an LPI
Conventional wisdom
-11 or 1 o’clock
Paradigm shift
3 or 9 o’clock
NEVER 12 O’CLOCK
Size for LPI
About 1.5mm
Hemorrhage in LPI
Just push on it
-gentle pressure with laser lens for a few seconds will tamponade the hemorrhage
IOP spike in LPI
Elevation >10mmHg in the first 3 hours occurs in ab out 25%
Most are transient, and respond to topical medications
Transient uveitis after LPI
- mild uveitis occurs in virtually 100% of iridotomy patients
- responds well to topical steroids
Diplopia and glare with LPI
- Placement is crucial
- specialty contacts with opaque periphery in very rare cases
Iridotomy closure after LPI
Confirmation of patency can be challenging, transillumination may fool you
Post op care for LPI
- Check IOP about 1 hour post procedure
- topical pred acetate 1% QID
- recheck in 5-7 days (global period is 10 days)
LPI summary
- confirm Dx with gonio
- perform with YAG, green or both
- pre treat with pilo, brimonidine
- consider temporal placement
- post is pred QID/re check in a week
Iridoplasty
Thermal laser to pull iris away from the TM
Rarely performed
- most useful in PI
- multiple burns placed concentrically close to iris insertion; more burns=more contraction
