Surgical Management of Glaucoma

Question 1

When is surgery the primary treatment modality for glaucoma?

Answer 1

ACG with pupillary block

Primary congenital glaucoma

Question 2

What does the CIGTS study show?

Answer 2

initial surgical treatment of glaucoma achieves better IOP control than Rx

However, patients have an increased risk of cataract formation

initial surgery also lead to decreased % of VF progression compared to Rx (except in patients with DM)

Question 3

What is laser trabeculoplasty?

Answer 3

application of laser energy to the TM in discrete spots, causing increased outflow

decreases IOP by 20-25%

Question 4

What are the indications for laser trabeculoplasty?

Answer 4

POAG
Pigmentary Glaucoma
Exfoliation Syndrome
Steroid-induced Glaucoma

Angle must be open for procedure to be effective

Question 5

What are contraindications for laser trabeculoplasty?

Answer 5

Inflammatory Glaucoma
ICE Syndrome
NV Glaucoma
Synechial Angle Closure
Developmental Glaucoma

Question 6

How is laser trabeculoplasty performed?

Answer 6

50uM laser is focused through a goniolens at the junction of pigmented and non pigmented TM

Question 7

How does SLT differ from ALT?

Answer 7

in SLT, there is selective absorption of laser energy by pigmented TM cells, causing less thermal damage to adjacent cells/tissues

Question 8

How successful is laser trabeculoplasty?

Answer 8

80% of patients experience an IOP decrease for 6 months s/p procedure

50% maintain IOP decrease for 3-5 years

Question 9

When is incisional surgery indicated for management of glaucoma?

Answer 9

in OAG when non-surgical modalities fail to maintain IOP at adequately low level

Question 10

What are the different types of filtering surgeries?

Answer 10

Creation of fistulas
Creation of filtering blebs
Re-Routing of aqueous drainage

Question 11

What are contraindications to incisional glaucoma surgery?

Answer 11

NLP (peform CB ablation instead)
Advanced anterior segment NV
Active Iritis
Rubeosis Iritis
CL dependent patients
Patients with decreased conjunctiva

Question 12

What is a trabeculectomy?

Answer 12

a partial thickness filtering procedure in which a block of peripheral corneoscleral tissue is removed beneath a scleral flap

anti-fibrotic agents can be used as well

Question 13

Where is the flap in a trabeculectomy usually located?

Answer 13

usually positioned superiorly at 1200, 8-10 mm posterior to limbus

Question 14

What is the MOA for 5 FU?

Answer 14

inhibits thymidylate synthetase, inhibiting DNA synthesis

if used in a trabeculectomy, position 180 degrees away from inferior fornix

Question 15

What is the MOA for MMC?

Answer 15

an anti-neoplastic/anti-bacterial agent that causes cross linking of DNA

AVOID INTRACAMERAL CONTACT

Question 16

What are risk factors for bleb failure during surgery?

Answer 16

Anterior segment NV
Black race
aphakia
prior failed filtering procedure
uveitis
prior CE
young age

Question 17

What is the initial management of bleb failure?

Answer 17

digital massage

Question 18

What surgical procedures are used to treat ACG with pupillary block?

Answer 18

laser iridotomy (argon or Nd:YAG laser)
incisional iridotomy

Question 19

What is the treatment for secondary angle closure glaucoma?

Answer 19

Treat the underlying cause

Question 20

Where should and LPI be located? Why?

Answer 20

LPI should be located peripherally, preferentially beneath the eyelid to prevent excess light from entering through the defect

Question 21

What is the contraindication for LPI?

Answer 21

rubeosis iritis

Question 22

Why is the Nd:YAG laser preferred to the argon laser when performing LPI?

Answer 22

preferred 2/2 no change in effect based off the color of the iris

Question 23

What are possible complications of LPI?

Answer 23

Disruption of anterior lens capsule/K endothelium
bleeding
post op IOP increase
delayed closure of iridotomy

Question 24

What is laser gonioplasty/peripheral iridoplasty?

Answer 24

technique to deepen the AC angle
primarily used in ACG patients with plateau iris
Involves burning the stroma of the iris, causing flattening of the peripheral iris

Question 25

What are indications to perform a peripheral iridectomy?

Answer 25

cloudy cornea
shallow/flat AC
insufficient patient cooperation

Question 26

What are the two types of glaucoma drainage devices?

Answer 26

Valved and non-valved

Valved are able to control the flow of aqueous

Question 27

What are the indications for drainage device implantation?

Answer 27

failed trabeculectomy with antifibrotic use
active uveitis
NV glaucoma
Inadequate conjunctiva
aphakia
CL use

Question 28

What are contraindications to drainage device implantation?

Answer 28

Borderline K endothelial dysfunction

Question 29

What is the preferred placement of the drainage device? Which type of valves must be primed before implantation? Where can the tubes from the devices be routed to?

Answer 29

Superotemporal quadrant is preferred, with the extra ocular plate sutured b/w the vertical and horizontal rectus muscles, posterior to their insertions

Valved devices must be primed prior to implantation

Tubes can be routed anteriorly to the chamber angle, the ciliary sulcus (pseudophakic eyes), or through the pars plana for posterior implantation (in pts s/p vitrectomy)

Question 30

When is CB ablation performed for glaucoma patients? How does it work?

Answer 30

Should be performed pts with poor visual potential or in pts who are poor candidates for incisional surgery

decreases aqueous production by destroying portion of the CB

Question 31

Why should incisional surgery be avoided in blind/NLP patients>

Answer 31

Incisional surgery should be avoided 2/2 risk of developing sympathetic ophthalmia

Question 32

What glaucoma surgery should be performed in patients who are blind/NLP?

Answer 32

diode laser photocoagulation