The document discusses the history and techniques of laser trabeculoplasty for treating glaucoma. It was first introduced in 1961 using light energy on the eye's anterior chamber angle. The first successful protocol in 1979 used argon laser and since then different laser types have been developed. Laser trabeculoplasty works by lowering eye pressure through various mechanical and biological mechanisms of the trabecular meshwork. The technique involves using a gonioscopic lens and laser settings are calibrated to the eye to apply spots treating areas of the angle to increase outflow with minimal complications.

1. Jagdish Dukre

2. Introduction
 In 1961, Zweng and Flocks introduced the concept
of applying light energy to the anterior chamber
angle for the treatment of glaucoma.
 In 1979, Wise and Witter described the first
successful protocol of what has become known as
laser trabeculoplasty

3.  1979 Argon Laser [488 nm blue-green, 514 nm
green]
 1984 Krypton Laser [red 647.1 nm, yellow 568.2
nm]
 1988 Nd:YAG Laser [1064 nm]
 1990 Diode Laser [810 nm]
 1996 Solid State “ALT” [532 nm]
 2001 Frequency Doubled Nd:YAG laser: SLT [532
nm]
 2006 Diode MicroPulse Laser: MLT [810 nm]
 2008 Titanium:Sapphire Laser [790 nm]

4. Indications
 when IOP remains above "target" IOP despite
maximally tolerated medical therapy
 when patients are noncompliant
 pseudoexfoliation glaucoma
 when surgery needs to be deferred due to a patient's
systemic status

5. Contraindications
 Narrow angles
 Presence of peripheral anterior synechiae
 Uveitis
 Advanced glaucoma
 Developmental glaucomas.

6.  Mechanical theory
 Biologic theory
 Cell division theory
Theories Of Mechanism

7. thermal energy
produced by
pigment absorption
shrinkage of
collagen in the
trabecular lamellae
shortening of the
treated meshwork
enlarge existing
spaces between
two treatment sites
Mechanical theory

8. Biologic Theory
 Laser energy causes tissue injury with a resultant
cascade of events.
 Upregulation of interleukin I and tumor necrosis factor
also upregulates metalloproteinase expression.
 Macrophages are attracted, and they alter the secreted
extracellular matrix, allowing an increased aqueous
outflow.

9. Cell Division Theory
 Laser applications stimulate cell division in the
anterior TM.
 Loss of endothelial cells over the trabecular beams
causes the peripheral corneal endothelial cells to
divide and slide over the lasered areas.
 These cells produce different extracellular matrix,
enhancing the aqueous outflow.

10. Preoperative Preparation
 Patients are instructed to continue all glaucoma
medications on their regular schedule.
 Patients are routinely pretreated with apraclonidine to
prevent a significant IOP spike that could adversely
affect visual function.
 The eye should not be exposed to diagnostic
procedures before the treatment because this can
affect corneal clarity.

11. Surgical Technique
 Argon laser trabeculoplasty is
performed using topical
anesthesia.
 The gonioscopic mirror of an
antireflection-coated, three-
mirror lens is used routinely.
 Ritch trabeculoplasty lens.
 A 17-diopter planoconvex
button lens over two mirrors
provides 1.4 magnification,
reducing a 50-µm laser spot to
35 µm

12.  Before starting treatment, it is critical to identify
the angle landmarks.
 The treatment begins with the gonioscopic mirror
at the 12 o'clock position viewing the inferior
angle.
 The inferior angle tends to be the most open part
and has the most pigmentation, making angle
structures more clearly defined in this area.
 This facilitates identification of the angle
landmarks and avoids treating the wrong part of
the angle.

13.  The use of a fixation light for the contralateral eye
assists the patient in maintaining the appropriate eye
position.
 Before the initiation of treatment, the eyepieces are
focused and the argon laser is set to the standard
treatment parameters: a spot size of 50 μm, a duration
of 0.1 seconds, and an average power of 800 mW (range
600 to 950 mW).

14.  During the treatment, the power setting required to
blanch the trabecular meshwork or cause a small
bubble formation is empirically determined.
 It is helpful to use a standardized treatment technique.
This involves starting with the mirror at the 12 o'clock
position and rotating it in a clockwise manner.

15.  The laser burns are placed at the anterior border of
the pigmented trabecular meshwork.
 The more posterior the treatment, the greater the
incidence of IOP elevation and formation of posterior
synechiae.

16.  The aiming beam should be the smallest and roundest
target possible.
 This can be achieved by mechanically directing the
laser beam forward and backward.
 If the treating contact lens is tilted and not
perpendicular to the eye, the aiming beam will appear
oval.
 the lens on the eye and making sure that the aiming
beam is perpendicular to the lens ensures that the full
power density of the treatment will be achieved.
 If the trabecular meshwork cannot be seen easily,
having the patient move the eye in the direction of the
gonioscopic mirror often opens the angle and improves
visibility.

17.  The spacing of the laser burns is the same whether 180°
or 360° are treated, that is, 20 to 25 burns per 90° of
angle treated, regardless of the area treated.

18. POSTOPERATIVE
MANAGEMENT
 The patient is instructed to continue all glaucoma
medications as usual and begin a topical steroid drop
four times a day for 4 to 5 days.
 If the patient has had a significant IOP elevation or has
severe glaucomatous damage, the IOP is measured the
next day.
 Most patients are reexamined 2 to 5 days later and
then at about 4 weeks.
 If at 4 weeks the pretreatment goal has not been
achieved, the second half of the angle can be treated.

19. Complications
 Transient IOP elevation
 Iritis
 peripheral anterior synechiae
 membrane covering the entire trabecular
meshwork

20. Transient IOP elevation
 the pressure rise is mild and lasts less than 24 hours
 IOP rise occurs within 2 hours after treatment in most
cases
 IOP rise occurs within 2 hours after treatment in most
cases
 mechanism of posttrabeculoplasty pressure rise is an
inflammatory reaction, with fibrinous material and tissue
debris in the meshwork

21. Iritis
 common early posttrabeculoplasty complication
 49% eyes showed significant inflammation
 inflammation peaked 2 days after the treatment
 More frequent in eyes with exfoliation syndrome or
pigmentary glaucoma
 It is mild and transient and easily controlled with a brief
postoperative course of topical corticosteroids
 postoperative management includes prednisolone 1%,
or fluorometholone 0.1%, four times daily for 5 days

22. Peripheral Anterior
Synechiae
 The formation of peripheral anterior synechiae is
also a common complication of trabeculoplasty.
 These are typically small and tented, corresponding
to the location of the laser applications.

23. Membrane
 most serious late posttrabeculoplasty complication
 Histopathologic studies show changes in the trabecular
meshwork, including an endothelial layer over the inner
surface
 It can lead to an increase in resistance to aqueous outflow.
 It is more common in eyes in which a higher number of
trabeculoplasties was performed

24. Selective Laser Trabeculoplasty
 frequency-doubled Q-switched 532-nm Nd:YAG laser.
 repeatable procedure because of the lack of
coagulation damage to the trabecular meshwork.
 A total of approximately 50 to 60 adjacent,
nonoverlapping spots are placed over 180 degrees of
the trabecular meshwork with energy ranging from
0.5 to 1.2 mJ per pulse, set to prevent bubble
formation

25.  A Latina lens, Goldmann 3 mirror or Ritch lens is used
for he procedure
 The aim is to cover the angle, but taking care that the
laser spot should not impinge upon the iris
 3 nanoseconds (preset); Spot Size: 400 microns
(preset); Energy: 1.0 mJ/pulse

26.  It targets the melanocytes in the trabecular
meshwork.
 The biologic response in the trabecular meshwork
results in release of cytokines that trigger
macrophage recruitment.
 This in turn causes IOP reduction by increased
aqueous outflow through the TM.
 SLT treats the meshwork without causing any thermal
or coagulative damage to the surrounding structures

28. TITANIUM:SAPPHIRE LASER
TRABECULOPLASTY

30. Thank You…