Lecture 13 - To drop or to chop Flashcards
What is better overal surgery or medication?
Medication
What are the disadvantages of using drugs?
- Maybe more expensive in the long run
- Multiple drugs
- Chronic drug use and its effect on future surgical outcomes
- Increased chances of cataract formation (higher chance in surgery though)
Which individuals who have a higher chance of post surgical scarring, less pigmented or higher pigmentation?
Higher pigmentations
Older or younger are better suited for surgery?
Older. Younger individuals will heal faster and maybe harder to control
When is surgery indicated?
Maximal medical therapy has been tried and failed
Which three glaucoma drugs are treated differently than OAG?
- Secondary glaucoma
- Congenital glaucoma
- Complete Angle closure
Even though the exact mechanism isn’t known for increasing outflow using a laser, what does the mechanical theory state and what laser induced cellular changes have occurred?
Mechanical tightening of TM and Macrophages migrate to the location
Note: The laser is called Argon Laser Trabeculoplasty
What are the indications of Argon Laser Trabeculoplasty?
Open Angle
Require decrease in IOP
Both POAG and secondary like pseudoexfoliation or pigmentary
Who are considered poor candidates?
- Angle recession, uveitic glacuoma, aphakia, high IOP (35 or greater), high episcleral venous pressure
- Very young individuals
- Previous 360 degree ALT
List the procedure for ALT?
Anesthetic and goniolens with coupling fluid
Clear view is a must
Ideal lens Ritch lens (good view, optics most suitable and least collateral damage)
Recommended spot size is 50 micro meter and 0.1 second duration
Power 0.5 W to1.0 W
Ideally tissue should blanch or small bubble should form
Eight (8) burns per clock hour
Location of burn- junction of non-pigmented and pigmented meshwork
50 burns per session (two sittings ideal)
or 100 burns per 360 degrees of meshwork (that is total)
What is the post-operative management?
Remain in office for 1 hour at least
Monitor IOP
1% apraclonidine immediately after procedure
Topical CAI or pilocarpine may be considered or oral hyperosmotic agents
Steroid use for 4 days
Prednisolone acetate 1% 4 times a day for 4 days
Continue IOP lowering medications if already on it
Follow-up schedule 1,4 and 8 weeks (approx 2 months)
Note: If IOP still high
Consider doing other 180 degree if option (4 weeks later)
What is the success rate for POAG after ALT?
75% to 80%
Note: Failure is usually seen in the first year
What is the success rate for NTG after ALT?
50% to 70%
Whats the biggest difference between ALT vs. SLT?
SLT does not scar
What does SLT target?
Intracytoplasmic pigment granules and trabecular endothelial cells
Mechanism of Action:
5-8 fold increase in monocytes and macrophages in TM
What is the procedure of SLT?
Frequency doubled Q-switched Nd:YAG laser
532 nm
Pulse 3 nanosecond
Spot size 400 micro meter
Beam focused over pigmented TM Standard therapy 50-100 adjacent non-overlapping spots over 180-360 degrees Power 0.8mJ (0.2 to 1.7mJ) Heavily pigmented eyes – lower power Endpoint- tiny “champagne” bubbles
What does SLT target in the TM?
Melanin pigment
What are the post-operative considerations?
Anti-inflammatory medications - post SLT prophylaxis - NSAIDs or steriods
What surgery do you use for Primary angle closure?
Peripheral Iridotomy
What are the chances of the fellow eye getting Acute Primary Angle Closure, if one of the eyes already sufferred the attack?
50% chance
What are the three contraindications for Peripheral Iridotomy?
1.Significant edema
Unable to visualize iris
2.Thick iris
Dilated pupil. bunched up iris
3.High risk of complications
Significant inflammation
How does Laser Iridoplasty work?
1.Procedure to open an appositionally closed angle
2.Series of laser burns Low power Large spot Longer duration Extreme peripheral iris
- This causes tightening of peripheral iris creates a space between anterior iris surface and trabecularmeshwork
How does Trabeculectomy work?
- Creates a fistula that allows aqueous from anterior chamber to subtenons space
- Fistula guarded by scleral flap
- The belb should not be fully vascularized neither completely avascular
- Mytomycin C (alkylating agent) or other antimetabolites (example 5-flurouracil) prevents scarring and failure
What are the indications of Glaucoma implants?
- Uncontrolled glaucoma
- Poor candidates for tabeculectomy
- Neovascular glaucoma,
- Penetrating keratoplasty or retinal detachments with glaucoma
- ICE syndromes traumatic glaucoma, previously failed trabeculectomy
