Lecture 13 - To drop or to chop

Question 1

What is better overal surgery or medication?

Answer 1

Medication

Question 2

What are the disadvantages of using drugs?

Answer 2

1. Maybe more expensive in the long run
2. Multiple drugs
3. Chronic drug use and its effect on future surgical outcomes
4. Increased chances of cataract formation (higher chance in surgery though)

Question 3

Which individuals who have a higher chance of post surgical scarring, less pigmented or higher pigmentation?

Answer 3

Higher pigmentations

Question 4

Older or younger are better suited for surgery?

Answer 4

Older. Younger individuals will heal faster and maybe harder to control

Question 5

When is surgery indicated?

Answer 5

Maximal medical therapy has been tried and failed

Question 6

Which three glaucoma drugs are treated differently than OAG?

Answer 6

1. Secondary glaucoma
2. Congenital glaucoma
3. Complete Angle closure

Question 7

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?

Answer 7

Mechanical tightening of TM and Macrophages migrate to the location

Note: The laser is called Argon Laser Trabeculoplasty

Question 8

What are the indications of Argon Laser Trabeculoplasty?

Answer 8

Open Angle
Require decrease in IOP
Both POAG and secondary like pseudoexfoliation or pigmentary

Question 9

Who are considered poor candidates?

Answer 9

1. Angle recession, uveitic glacuoma, aphakia, high IOP (35 or greater), high episcleral venous pressure
2. Very young individuals
3. Previous 360 degree ALT

Question 10

List the procedure for ALT?

Answer 10

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)

Question 11

What is the post-operative management?

Answer 11

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)

Question 12

What is the success rate for POAG after ALT?

Answer 12

75% to 80%

Note: Failure is usually seen in the first year

Question 13

What is the success rate for NTG after ALT?

Answer 13

50% to 70%

Question 14

Whats the biggest difference between ALT vs. SLT?

Answer 14

SLT does not scar

Question 15

What does SLT target?

Answer 15

Intracytoplasmic pigment granules and trabecular endothelial cells

Mechanism of Action:
5-8 fold increase in monocytes and macrophages in TM

Question 16

What is the procedure of SLT?

Answer 16

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

Question 17

What does SLT target in the TM?

Answer 17

Melanin pigment

Question 18

What are the post-operative considerations?

Answer 18

Anti-inflammatory medications - post SLT prophylaxis - NSAIDs or steriods

Question 19

What surgery do you use for Primary angle closure?

Answer 19

Peripheral Iridotomy

Question 20

What are the chances of the fellow eye getting Acute Primary Angle Closure, if one of the eyes already sufferred the attack?

Answer 20

50% chance

Question 21

What are the three contraindications for Peripheral Iridotomy?

Answer 21

1.Significant edema
Unable to visualize iris

2.Thick iris
Dilated pupil. bunched up iris

3.High risk of complications
Significant inflammation

Question 22

How does Laser Iridoplasty work?

Answer 22

1.Procedure to open an appositionally closed angle

2.Series of laser burns
Low power
Large spot
Longer duration
Extreme peripheral iris

3. This causes tightening of peripheral iris creates a space between anterior iris surface and trabecularmeshwork

Question 23

How does Trabeculectomy work?

Answer 23

1. Creates a fistula that allows aqueous from anterior chamber to subtenons space
2. Fistula guarded by scleral flap
3. The belb should not be fully vascularized neither completely avascular
4. Mytomycin C (alkylating agent) or other antimetabolites (example 5-flurouracil) prevents scarring and failure

Question 24

What are the indications of Glaucoma implants?

Answer 24

1. Uncontrolled glaucoma
2. Poor candidates for tabeculectomy
3. Neovascular glaucoma,
4. Penetrating keratoplasty or retinal detachments with glaucoma
5. ICE syndromes traumatic glaucoma, previously failed trabeculectomy