1. Lasers in angle closure
Dr. Thomas George T.
Consultant
Chaithanya Eye Hospital,
Trivandrum

2. Mechanism Pupillary block 3. Iris baloons forward and closes angle
1. Resistance to flow at pupil
2. Pressure behind iris rises
3. Iris baloons forward and closes angle

3. Treatment
Laser iridotomy

4. Pupillary block Relative pupillary block (PACG)
Oclutio and seclutio (Posterior synechie or membrane)
Inverse pupillary block
Reverse pupillary block (Pigmentary glaucoma)

5. Typical pupillary block – mid dilated pupil

6. Reverse pupillary block – Pigment dispersion
Floppy iris
Drapes over zonules
Aqueos collects behind
Comes to AC as a bolus
AC pressure higher than PC

7. Reverse Pupilllary block
Peripheral iris
bowed backwards

8. Inverse pupillary block - Spherophakia

9. Indications
Acute angle-closure glaucoma
Fellow eye
Narrow/occludable angle
Pigmentary dispersion syndrome

10. Indications Miscellaneous conditions
phacomorphic glaucoma, aqueous misdirection, nanophthalmos and plateau iris syndrome
To exclude pupillary block to confirm

11. Contraindications Conditions causing poor visualization of the iris
Corneal edema
Corneal opacity
Flat anterior chamber
Non pupillary block synechial closure
Neovascular glaucoma
Iridocorneal endothelial syndrome

12. Procedure Explain to patient and informed consent
Constrict pupil with pilocarpine (2% at least 3 times and wait 1/2hour)
Seat patient comfortable at NdYag laser slitlamp delivery
(1024nm infrared q switched mode locked(pulsed))
Burst mode (3bursts)
Total power around 10mJ

13. Procedure Instil topical anaesthetic drops
Insert Abram’s Iridotomy lens

14. Why use the lens? See iris magnified to identify crypts
Increase cone angle of laser
Laser energy concentrated at level of iris
Corneal epithelial burns is minimized (lens acts as a heat sink)
Acts as a speculum
Minimizes fine eye movements

15. Why use the lens? Laser energy Concentrated (tissue effect)
Laser energy spread out
(not much tissue effect)
+66 D lens
Laser energy Concentrated over less distance
(tissue effect over less space – less collateral damage)

16. Procedure Identify a crypt Defocus – ?
Hit same spot repeatedly till pigment layer is breached and aqueous flows
Size 200microns or 0.2 mm (estimate)
Should visualize tissue behind through PI
(If stroma fluffs up and can’t focus on base repeat after 2 days)

17. Argon laser (Thick iris)
Argon laser or any photocoagulation laser
Hump technique – a localized elevation is created with
a large diameter, low energy burns & then it is
penetrated with a small, intense burn (or YAG).
Drumhead technique
large diameter, low energy burns are put around the intended treatment site
Penetrated with small diameter, high energy burn

19. Complications Hyphema Injury to Descemets - compromises visualization
Stop and repeat after 3-4 days
Go to new site
Capsule injury – Cataract will form

20. Post procedure Check IOP after 30 mins to 1 hour
Sometimes Very high IOP spikes can occur
If IOP high deal with it medically
Topical steroids for 1 week at least
See patient after 1 week
IOP, repeat Gonioscopy to rule out other causes of closure
(Dilated exam can be done now)

21. Quite a few angles do not open up or widen with PI
Other mechanisms of closure

22. Mechanism – 2 Lens related Anterior position of lens Size of lens
Shape of lens (more spherical)

23. Mechanism – 3 Anterior rotation of ciliary body
2. Contraction pulls ciliary body forward and in
1. Ciliary muscle attached to scleral spur
3. Zonules relax and lens iris diaphragm move forward

24. Mechanism – 4
Anteriorly placed ciliary processes
(Plateau iris)

25. Plateau Iris configuration
Plateau iris configuration can be missed without gonioscopy.
Note the beam on iris in the left hand side picture is a straight line, dipping into the angle recess sharply.
With indentation one can see the sine wave sign as the iris drapes over the anteriorly placed ciliary processes

26. In a given patient Combination of multiple mechanisms
Each contributing a variable extend
Explaining variation in response to Rx

27. You expect PI to sort out problems..if

28. Closure Synechiae ACG Appositional ACG Creeping ACG
Now I will take you through a few specific features.
PAS of appositional closure tend to be rounded with some areas more anterior than others.
In contrast a creeping ACG pas is uniform all over in terms of height. These patients go into the chronic ACG without ever having an acute attack.

29. Non closure Synechiae Inflammatory
Irregular
More inferiorly
Differentiate from iris processes (normal)
In contrast inflammatory PAS have an irregular moth-eaten anterior edge. They can also be point synechiae or tent synechia.
They need to be differentiated from iris strands going on to the trab meshwork called iris processes.

30. Plateau Iris configuration
Sine wave sign
On indentation
Plateau
Plateau iris configuration can be missed without gonioscopy.
Note the beam on iris in the left hand side picture is a straight line, dipping into the angle recess sharply.
With indentation one can see the sine wave sign as the iris drapes over the anteriorly placed ciliary processes

31. Case
PI Patent BE
Gonioscopy Grade 0 all around
Closed angles

32. Case
On indentation

33. Other options
Pilocarpine
Peripheral Iridoplasty
Pupilloplasty

34. Peripheral Iridoplasty
Photocoagulation lasers – Argon/Diode
Put a row of laser spots on peripheral iris to shrink it away from angles
If too peripheral will cause inflammatory PAS

35. Pupilloplasty You need a round pupil to cause pupillary block
Use photocoagulating laser to peak pupil by putting laser spots near pupil edge in a sector
Useful in Acute closure
Too hazy for PI
Edematous iris not allowing for PI

36. Thank you