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Laser Trabeculoplasty
What You Must Know Before Having It Done
By Dr. David Richardson
David-Richardson-MD.com
Originally published as seven articles on
New-Glaucoma-Treatments.com
Laser Trabeculoplasty
What You Must Know Before Having It Done
By Dr. David Richardson
David-Richardson-MD.com
Originally published as seven articles on
New-Glaucoma-Treatments.com
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LASER
TRABECULOPLASTY
SURGERY:
WHAT YOU MUST KNOW BEFORE HAVING IT DONE
LASER
TRABECULOPLASTY
New Glaucoma Treatments is a GLAUCOMA HealthHub maintained by multi-awarded
Glaucoma Eye Doctor in California, Dr. David Richardson. It’s primary purpose is to provide
valuable information to glaucoma patients and their caregivers worldwide about the latest
developments and treatments for glaucoma, while providing answers to commonly asked
questions about glaucoma, care and treatment options. All articles are either written by
Dr. David Richardson or by professional health topics writers (reviewed by Dr. David
Richardson prior to publishing).
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Contents
Introduction to Laser Trabeculoplasty1
Laser Trabeculoplasty. A Quick History.1
Types of Laser Trabeculoplasty3
Argon Laser Trabeculoplasty (ALT)3
Selective Laser Trabeculoplasty (SLT) 3
Micropulse Laser Trabeculoplasty (MLT) 4
How Well Does Laser Trabeculoplasty Work?6
Argon Laser Trabeculoplasty (ALT)6
Selective Laser Trabeculoplasty (SLT)7
Micropulse Laser Trabeculoplasty (MLT)8
Can Laser Trabeculoplasty Be Repeated?9
What Are the Risks of Laser Trabeculoplasty
11
Commonly Encountered Complications Associated with LT
11
Who Should Consider Laser Trabeculoplasty? 13
Who Should Consider Glaucoma Treatments
Other than Laser Trabeculoplasty15
How To Choose Which Type Of Laser Trabeculoplasty To Have
17
Why, then, would anyone choose to have ALT?
17
Summary18
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Introduction to Laser Trabeculoplasty
In most open angle glaucomas the
aqueous fluid is unable to pass through the
Trabecular Meshwork (drainage grate inside
the eye) as easily as it should.[1] Partly due
to this knowledge, most surgical treatments
of glaucoma have focused on improving
passage of fluid across this meshwork or
simply bypassing the meshwork altogether.
Laser Trabeculoplasty. A Quick History.
Laser trabeculoplasty attempts to improve flow of fluid across the trabecular
meshwork by focusing wavelengths of light onto the trabecular meshwork. The
concept of using light energy to open up the trabecular meshwork dates back to
1961.[2] Lasers were not yet available for clinical research as they had only been
invented the year prior to that. Rather, a xenon-arc photocoagulator was used
on the trabecular meshwork of animals resulting in a reduction in intraocular
pressure (IOP).
It was not until the early 1970s that lasers were used in an attempt to punch
holes through the trabecular meshwork.[3] These microscopic holes, however,
closed down with time. Ironically, in 1975 it was reported that application of
1
Grant WM. Further studies on facility of flow through the trabecular meshwork. AMA Arch Ophthalmol.
1958;60(4 Part 1):523-33.
Grant WM. Experimental aqueous perfusion in enucleated human eyes. Arch Ophthalmol. 1963;69:783801.
2
Zweng HC, flocks M. Experimental photocoagulation of the anterior chamber angle. A preliminary report.
Am J Ophthalmol. 1961;52:163-165.
3
Worthen DM, Wickham MG. Argon laser trabeculotomy. Trans Am Acad Ophthalmol Otolaryngol.
1974;78(2):OP371-OP375.
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1
laser energy in an attempt to coagulate (or melt) the trabecular meshwork
could be used to experimentally create glaucoma in monkeys.[4]
In a twist that is typical of scientific discovery, another set of scientists
discovered that some of these monkeys ended up with long-term lowering
of their IOP.[5] By 1979 what we think of as Laser Trabeculoplasty (LT) was
introduced in humans.[6] Essentially, 50-100+ very short laser pulses are used
to gently irradiate the trabecular meshwork. No holes are created, but for
reasons that are not entirely understood, this allows fluid to more easily leave
the eye.
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4
Gaasterland D, Kupfer C. Experimental glaucoma in the rhesus monkey. Invest Ophthalmol.
1974;13(6):455-457.
5
Ticho U, Zauberman H. Argon laser application to the angle structures in the glaucomas. Arch Ophthalmol. 1976;94(1):61-64.
6
Wise JB, Witter SL. Argon laser therapy for open-angle glaucoma. A pilot study. Arch Ophthalmol.
1979;97(2):319-322.
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2
Types of Laser Trabeculoplasty
There are three types of lasers currently used for trabeculoplasty glaucoma
surgery: Argon, “Selective”, and Micropulse.
Argon Laser Trabeculoplasty (ALT)
This type of laser has been around the longest. It is generally performed in one
or two sessions. However, it can result in microscopic scars called “peripheral
anterior synechiae”[7] that can limit the effectiveness of the treatment as well as
future surgeries (such as canaloplasty).
Selective Laser Trabeculoplasty (SLT)
Selective Laser Trabeculoplasty (SLT) was first reported in 1995.[8] It uses a
7
Rouhianinen HJ, Teravirta ME, Tuovinen EJ. Peripheral anterior synechiae formation after trabeculoplasty. Arch Ophthalmol. 1988;106(2):189-191.
8
Latina MA, Park C. Selective targeting of trabecular meshwork cells: in vitro studi es of pulsed and CW la
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3
“Q-switched, frequency-doubled Nd:YAG laser”. This laser energy is
preferentially absorbed by the pigment-containing cells in the trabecular
meshwork while cells without pigment are left undamaged.[9] Because SLT does
not “coagulate” (or melt) tissue this results in a less traumatic laser treatment
compared to ALT.[10]
SLT appears to cause less damage to the eye
tissue and uses less than 1% of the energy
required for ALT.[11] It is rapidly becoming
the preferred method of laser surgery
(over ALT) for treating primary open angle
glaucoma. It can also be performed on
patients who have already had received a full treatment of ALT.[12]
Micropulse Laser Trabeculoplasty (MLT)
Micropulse Diode Laser Trabeculoplasty
(MDLT or MLT) is the latest addition to the
Laser Trabeculoplasty party. MLT works by
using very short bursts of the laser (called
“micro-pulses) to heat up the trabecular
ser interactions. Exp Eye Res. 1995; 60:359-71.
9
Latina MA, park C. Selective targeting of trabecular meshwork cells: in vitro studies of pulsed and CW
laser interactions. Exp Eye Res. 1995;60(4):359-371.
Latina MA, Sibayan SA, Shin DH, et al. Q-switched 532-nm Nd:YAG laser trabeculoplasty (selective laser
trabeculoplasty): a multicenter, pilot, clinical study. Ophthalmology. 1998;105(11):2082-2088; discussion
2089-2090.
10 KramerTR, Noecker RJ. Comparison of the morphologic changes after selective laser trabeculoplasty and
argon laser trabeculoplasty in human eye bank eyes. Ophthalmology. 2001;108:773-9.
11 Samples JR, Singh K, Lin SC, et al. Laser trabeculoplasty for open-angle glaucoma: a report by the American Academy of Ophthalmology.Ophthalmology. 2011;118:2296-302.
12 Damji KF, Shah KC, Rock WJ, et al. Selective laser trabeculoplasty v argon laser trabeculoplasty: a prospective randomised clinical trial. Br J Ophthalmol. 1999;83(6):718-722.
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4
meshwork cells without destroying them. This avoids the damage and scarring
associated with ALT while minimizing the inflammation and post-operative
IOP elevations seen with both ALT and SLT.[13]
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13 Fudemberg, SJ, Myers, JS, Katz, LJ: Trabecular Meshwork Tissue Examination with Scanning Electron
Microscopy: A Comparison of Micropulse Diode Laser (MLT), Selective Laser (SLT), and Argon Laser
(ALT) Trabeculoplasty in Human Cadaver Tissue. Invest. Ophthalmol. Vis. Sci. 2008;49(5):1236.
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How Well Does Laser Trabeculoplasty Work?
Argon Laser Trabeculoplasty (ALT)
Argon Laser Trabeculoplasty (ALT) successfully lowers the intraocular pressure
(IOP) in just over 80% of the eyes that receive this treatment.[14] IOP lowering
may not be realized for up to a month after the treatment. On average the IOP
is reduced by 6-9mmHg.[15] Unfortunately, the effect does not last. After a few
14 Wise JB, Witter SL. Argon laser therapy for open-angle glaucoma. A pilot study. Arch Ophthalmol.
1979;97(2):319-322.
Wise JB. Long-term control of adult open angle glaucoma by argon laser treatment. Ophthalmology.
1981;88(3):197-202.
Schwartz AL, Whittn ME, Bleiman B, et al. Argon laser trabecular surgery in uncontrolled phakic open
angle glaucoma. Ophthalmology. 1981;88(3):203-212.
Wilensky JT, Jampol LM. Laser therapy for open angle glaucoma. Ophthalmology. 1981;88(3):213-217.
Forbes M, Bansal RK. Argon laser goniophotocoagulation of the trabecular meshwork in open-angle glaucoma. Trans Am Ophthalmol Soc. 1981;79:257-275.
Lichter PR. Argon laser trabeculoplasty. Trans Am Ophthalmol Soc. 1982;80:288-301.
Thomas JV, Simmons RJ, Belcher CD III. Argon laser trabeculoplasty in the presurgical glaucoma patient.
Ophthalmology. 1982;89(3):187-197.
15 Pollack IP, Robin AL, Sax H. The effect of argon laser trabeculoplasty on the medical control of primary
open-angle glaucoma. Ophthalmology. 1983;90(7):785-789.
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ars additional treatment is generally needed to lower the IOP.[16]
Selective Laser Trabeculoplasty (SLT)
Selective Laser Trabeculoplasty (SLT) success is dependent upon how much of
the trabecular meshwork is treated. When only half of the trabecular meshwork
is treated (180 degrees) SLT successfully lowers the intraocular pressure (IOP)
65% of the time with an average reduction in IOP of just over 4mmHg (range
of 2 to 18mmHg).[17] However, when a full 360 degree treatment is applied the
IOP can be expected to be reduced in almost all eyes by 11-40%.[18] In general
SLT appears to work as well as ALT.[19]
16 Schwartz AL, Kopelman J. Four-year experience with argon laser trabecular surgery in uncontrolled openangle glaucoma. Ophthalmology. 1983;90(7):771-780.
Tuulonen A, Niva AK, Alanko HI. A controlled five-year follow-up study of laser trabeculoplasty as primary therapy for open-angle glaucoma. Am J Ophthalmol. 1987;104(4):334-338.
Grinich NP, Van Buskirk EM, Samples JR. Three-year efficacy of argon laser trabeculoplasty. Ophthalmology. 1987;94(7):858-861.
Shingleton BJ, Richter CU, Bellows AR, et al. Long-term efficacy of argon laser trabeculoplasty. Ophthalmology. 1987;94(12):1513-1518.
Ticho U, Nesher R. Laser trabeculoplasty in glaucoma. Ten-year evaluation. Arch Ophthalmol.
1989;107(6):844-846.
Spaeth GL, Baez KA. Argon laser trabeculoplasty controls one third of cases of progressive, uncontrolled,
open angle glaucoma for 5 years. Arch Ophthalmol. 1992;110(4):491-494.
Spiegel D, Wegscheider E, Lund OE. Argon laser trabeculoplasty: long-term follow-up of at least 5 years.
Ger J Ophthalmol. 1992;1(3-4):156-158.
Shingleton BJ, Richter CU, Dharma SK, et al. Long-term efficacy of argon laser trabeculoplasty. A 10-year
follow-up study. Ophthalmology. 1993;100(9):1324-1329.
17 Kajiya S, Hayakawa K, Sawaguchi S. Clinical results of selective laser trabeculoplasty. Jpn J Ophthalmol.
2000;44(5):574-575
18 Lanzetta P, Menchini U, Virgili G. Immediate intraocular pressure response to selective laser trabeculoplasty. Br J Ophthalmol. 1999;83(1):29-32.
Stein JD, Challa P. Mechanisms of action and efficacy of argon laser trabeculoplasty and selective laser
trabeculoplasty. Curr Opin Ophthalmol. 2007;18:140-5.
19 Wong MOM, Lee JWY, Choy BNK, et al. Systematic review and meta-analysis on the efficacy of selective
laser trabeculoplasty in o pen-angle glaucoma. Surv Ophthalmol. 2014[Published online].
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Micropulse Laser Trabeculoplasty (MLT)
Although this is relatively new technology, it does appear promising. Initial
studies (though small) demonstrated reductions in IOP and need for
medications that are similar to those seen with ALT.[20] Larger studies are
underway.
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20 Ingvoldstad DD, Krishna R, Willoughby L. Micropulse diode laser trabeculoplasty versus argon laser trabeculoplasty in the treatment of open angle glaucoma. Invest Ophthalmol Vis Sci. 2005;46:e-abstract 123.
Detry-Morel M, Muschart F, Pourjavan S. Micropulse diode laser (810 nm) versus argon laser trabeculoplasty in the treatment of open-angle glaucoma: comparative short-term safety and efficacy profile. Bull
Soc Belge Ophthalmol. 2008;308:21-28.
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Can Laser Trabeculoplasty Be Repeated?
That depends upon the type of laser used. Only one full (360 degree) or two
partial (180 degree) treatments of Argon Laser Trabeculoplasty (ALT) can be
performed on an eye. Once a portion of the trabecular meshwork has been
treated with the Argon laser, additional treatments with ALT typically result in
either minimal IOP lowering[21] or a rapid decline in effect.[22] Selective Laser
Trabeculoplasty (SLT), however, can be effective after failed ALT.[23]
Selective Laser Trabeculoplasty (SLT) may be repeated multiple times so long as
there is an initial IOP-lowering response to the first treatment.[24] When SLT is
repeated after the first SLT treatment has worn off the IOP may be further
reduced by about 20% in 43-67% of treated eyes.[25] Eventually, however, re-
21 Starita RJ, Fellman RL, Spaeth GL, et al. The effect of repeating full-circumference argon laser trabeculoplasty. Ophthalmic Surg. 1984;15(1):41-43.
Brown SV, Thomas JV, Simmons RJ. Laser trabeculoplasty re-treatment. Am J Ophthalmol. 1985;99(1):810.
Messner D, Siegel LI, Kass MA, et al. Repeat argon laser trabeculoplasty. Am J Ophthalmol.
1987;103(1):113-115.
Richter CU, Shingleton BJ, Bellows AR, et al. Retreatment with argon laser trabeculoplasty. Ophthalmology. 1987;94(9):1085-1089.
Grayson DK, Camras CB, Podos SM, et al. Long-term reduction of intraocular pressure after repeat argon
laser trabeculoplasty. Am J Ophthalmol. 1988;106(3):312-321.
Weber PA, Burton GD, Epitropoulos AT. Laser trabeculoplasty retreatment. Ophthalmic Surg.
1989;20(10):702-706.
Feldman RM, Katz LJ, Spaeth GL, et al. Long-term efficacy of repeat argon laser trabeculooplasty. Ophthalmology. 1991;98(7):1061-1065.
Spiegel D, Wegscheider E, Lund OE. Argon laser trabeculoplasty: long-term follow-up of at least 5 years.
Ger J Ophthalmol. 1992;1(3-4):156-158.
22 Feldman RM, Katz LJ, Spaeth GL, et al. Long-term efficacy of repeat argon laser trabeculoplasty. Ophthalmology. 1991;98(7):1061-1065
23 Damji KF, Shah KC, Rock WJ, et al. Selective laser trabeculoplasty v argon laser trabeculoplasty: a prospective randomised clinical trial. Br J Ophthalmol. 1999;83(6):718-722.
24 Hong BK, Winer JC, Martone JF, et al. Repeat selective laser trabeculoplasty. J Glaucoma.
2009;18(3):180-183.
25 Avery N, Ang GS, Nicholas S, et al. Repeatability of primary selective laser trabeculoplasty in patients with
primary open-angle glaucoma. Int Ophthalmol. 2013;33:501-6.
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treatments lose their effect at which time medical or non-laser surgical options
must be considered if the IOP is too high.
There are currently no published
studies looking at the effect of repeated
Micropulse Laser Trabeculoplasty
(MLT). It is believed that thermal
damage is what limits the benefit of
repeated treatments. At least in theory,
as MLT does not result in thermal
damage to the trabecular meshwork it should be repeatable.
[On Photo: NEW MicroPulse™ Laser Trabeculoplasty (MLT) Lens via www.iridex.com]
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Hong BK, Winer JC, Martone JF, et al. Repeat selective laser trabeculoplasty. J Glaucoma. 2009;18:180-3.
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What Are the Risks of Laser Trabeculoplasty
Laser Trabeculoplasty is usually painless (though not always), fast, and
relatively safe. As such, it can be offered to almost anyone with open angle
glaucoma at almost any stage in the disease.
Commonly Encountered Complications Associated with LT
As with all surgical procedures, however, there are risks associated with Laser
Trabeculoplasty. Following are some of the more commonly encountered
complications associated with LT.
Intraocular Pressure Elevation (Spike)
The main risk of all Laser Trabeculoplasty treatments (or any glaucoma
laser treatment of the eye for that matter) is a spike in intraocular
pressure (IOP). Clearly, when one’s goal is to lower the IOP this is
undesirable. Fortunately, these elevations in IOP are generally shortlived. Rarely, however, the IOP will stay elevated which then requires
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additional non-laser glaucoma surgery for control.[26]
Because of this risk of developing increased eye pressure after LT,
many surgeons will treat only half of the trabecular meshwork at the
first session. The remaining trabecular meshwork can then be treated,
if necessary, at a later date. It is sometimes the case that treatment
of only half of the trabecular meshwork is required to achieve IOP
lowering.
Scarring of the Eye’s Drainage System (Peripheral Anterior Synechiae)
One notable risk of Argon Laser Trabeculoplasty (ALT) is scarring of
the drainage angle and Schlemm’s (drainage) Canal. This scarring is
called Peripheral Anterior Synechiae (PAS). It occurs in approximately
12-47% of eyes that have undergone ALT.[27]
Angle scarring had been considered a minor issue as it rarely
caused problems other than decreasing the effect of the ALT. Today,
however, there are multiple “Minimally Invasive Glaucoma Surgeries”
(MIGS) that may not work as well when there is scarring of the angle
structures. Fortunately, angle scarring is seen in less than 3% of eyes
treated with Selective Laser Trabeculoplasty (SLT).[28]
26 Harasymowycz PJ, Papamatheakis DG, Latina M, et al. Selective laser trabeculoplasty (SLT) complicated
by intraocular pressure elevation in eyes with heavily pigmented trabecular meshworks. Am J Ophthalmol.
2005;139:1110-3.
27 Thomas JV, Simmons RJ, Belcher CD 3rd. Argon laser trabeculoplasty in the presurgical glaucoma patient. Ophthalmology. 1982;8 9:187-97.
Traverso CE, Greenidge KC, Spaeth GL. Formation of peripheral anterior synechiae following argon laser
trabeculoplasty. A prospective study to determine relationship to position of laser burns. Arch Ophthalmol. 1984;102:861-3.
Rouhiainen HJ, Terasvirta ME, Tuovinen EJ. Peripheral anterior synechiae formation after trabeculoplasty. Arch Ophthalmol. 1988;106:189-91.
28 Wong MOM, Lee JWY, Choy BNK, et al. Systematic review and meta-analysis on the efficacy of selective
laser trabeculoplasty in o pen-angle glaucoma. Surv Ophthalmol. 2014[Published online].
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Because ALT may “close doors” on future MIGS options patients who
would benefit from Laser Trabeculoplasty should generally opt for SLT
or MLT where available. Of course, there are exceptions, but they are
rare.
Rarely encountered additional risks of Laser Trabeculoplasty include
corneal damage and swelling of the central retina (macula), both of
which could result in loss of vision.
Who Should Consider Laser Trabeculoplasty?
Most anyone with open angle glaucoma that requires treatment is a candidate
for Laser Trabeculoplasty. Although it is generally offered to patients in
the USA after drops have been tried (and failed), there is some evidence to
suggest that laser trabeculoplasty may work better if it is done prior to drop
use. Indeed, multiple studies support the use of laser trabeculoplasty as a
reasonable first choice in the treatment of glaucoma.[29]
29 Rosenthal AR, Chaudhuri PR, Chiapella AP. Laser trabeculoplasty primary therapy in open-angle glaucoma. A preliminary report. Arch Ophthalmol. 1984;102(5):699-701.
Thomas JV, El-Mofty A, Hamdy EE, et al. Argon laser trabeculoplasty as initial therapy for glaucoma. Arch
Ophthalmol. 1984;102(5):702-703.
Migdal C, Hitching R. Primary therapy for chronic simple glaucoma the role of argon laser trabeculoplasty.
Trans Ophthalmol Soc UK. 1985;104(1):62-66.
Sherwood MB, Lattimer J, Hitching RA. Laser trabeculoplasty as supplementary treatment for primary
open angle glaucoma. Br J Ophthalmol. 1987;71(3):188-191.
Tuulonen A, Koponen J, Alanko HI, et al. Laser trabeculoplasty versus medication treatment as primary
therapy for glaucoma. Acta Ophthalmol. 1989;67(3):275-280.
The Glaucoma Laser Trial Research Group. The Glaucoma Laser Trial (GLT). 2. Results of argon laser
trabeculoplasty versus topical medications. Ophthalmology. 1990;97(11):1403-1413.
Elsas T, Johnsen H. Long-term efficacy of primary laser trabeculoplasty. Br J Ophthalmol. 1991;75(1):3437.
The Glaucoma Laser Trial Research Group. The Glaucoma Laser Trial (GLT) and glaucoma laser trial
follow-up study: 7. Results. Am J Ophthalmol. 1995;120(6):718-731.
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Certain types of glaucoma seem to respond better to Laser Trabeculoplasty.
Pseudoexfoliation glaucoma and pigmentary glaucoma respond particularly
well to this treatment.[30]
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30 Forbes M, Bansal RK. Argon laser goniophotocoagulation of the trabecular meshwork in open-angle glaucoma. Trans Am Ophthalmol Soc. 1981;79:257-275.
Pohjanpelto P. Argon laser trabeculoplasty of the anterior chamber angle for increased intraocular pressure. Acta Ophthalmol. 1981;59(2):211-220.
Brooks AM, Gillies WE. Do any factors predict a favorable response to laser trabeculoplasty? Aust J Ophthalmol. 1984;12(2):149-153.
Robin AL, Polack IP. Argon laser trabeculoplasty in secondary forms of open-angle glaucoma. Arch Ophthalmol. 1983;101(3):382-384.
Lieberman MF, Hoskins HD Jr, Hetherington J Jr. Laser trabeculoplasty and the glaucomas. Ophthalmology. 1983;90(7):790-795.
Lunde MW. Argon laser trabeculoplasty in pigmentary dispersion syndrome with glaucoma. Am J Ophthalmol. 1983;96(6):721-725.
Ritch R, Liebmann J, Robin A, et al. Argon laser trabeculoplasty in pigmentary glaucoma. Ophthalmology.
1993;100(6):909-913.
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Who Should Consider Glaucoma Treatments
other than Laser Trabeculoplasty
Laser Trabeculoplasty, by definition, requires that the trabecular meshwork be
visible in order to apply laser to it. Those with closed or scarred angles cannot
expect to benefit from this treatment. Because Argon Laser Trabeculoplasty
results in post-operative inflammation it is generally not recommended for
those who already have active inflammation (iritis, uveitis) in the eye.[31]
Selective Laser Trabeculoplasty (SLT), however, may be considered even in
those with a history of inflammation in the eye.[32] Laser Trabeculoplasty is
also not expected to benefit those with angle-recession glaucoma (usually seen
after trauma to the eye) or in infant and childhood glaucomas.[33] Finally, its
effect may be limited in eyes that have had multiple prior glaucoma operations.
The response to Laser Trabeculoplasty appears to be dependent upon the
pre-treatment intraocular pressure (IOP). In other words, the higher the IOP
before treatment, the better the response to Laser Trabeculoplasty.[34] For
example, Laser Trabeculoplasty can only be expected to lower the IOP by 1416% in those with Normal Tension Glaucoma.[35] At the other extreme, when
the pre-treatment IOP is higher than 30mmHg Laser Trabeculoplasty is more
31 Siddique SS, Suelves AM, Baheti U, Foster CS. Glaucoma and Uveitis. Surv Ophthalmol. 2013;58(1):1-10.
32 Pujari S, Siddique SS, Zakka F et al. Selective LaserTrabeculoplasty for Uveitic Glaucoma: A One-Year Follow Up. Submitted to Ocular Immunology and Inflammation.
33 Robin AL, Pollack IP. Argon laser trabeculoplasty in secondary forms of open-angle glaucoma. Arch Ophthalmol. 1983;101(3):382-384.
Lieberman MF, Hoskins HD Jr, Hetherington J Jr. Laser trabeculoplasty and the glaucomas. Ophthalomology. 1983;90(7):790-795.
34 Kano K, Kuwayama Y, Mizoue S, et al. Clinical results of selective laser trabeculoplasty [in Japanese]. Nippon Ganka Gakkai Zasshi. 1999;103(8):612-616.
35 El Mallah MK, Walsh MM, Stinnett SS, et al. Selective laser trabeculoplasty reduces mean IOP and IOP
variation in normal tension glaucoma patients. Clin Ophthalmol. 2010;4:8 89-93.
Nitta K, Sugiyama K, Mawatari Y, et al. Results of selective laser trabeculoplasty (SLT) as initial treatment
for normal tension glaucoma. Nihon Ganka Gakkai Zasshi. 2013;117:335-43.
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likely to fail.[36] Thus, patients with an IOP greater than 30mmHg may not be
the best candidates for Laser Trabeculoplasty.
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36 Tuulonen A, Airaksinen PJ, Kuulasmaa K. Factors influencing the outcome of laser trabeculoplasty. Am J
Ophthalmol. 1985;99(4):388-391.
The AGIS Investigators. The Advanced Glaucoma Intervention Study (AGIS): 11. Risk factors for failure of
trabeculectomy and argon laser trabeculoplasty. A J Ophthalmol. 2002;134(4):481-498.
LASER
TRABECULOPLASTY
SURGERY:
WHAT YOU MUST KNOW BEFORE HAVING IT DONE
LASER
TRABECULOPLASTY
16
How To Choose Which Type Of Laser
Trabeculoplasty To Have
For those who are candidates for Laser Trabeculoplasty, Selective Laser
Trabeculoplasty (SLT) or Micropulse Laser Trabeculoplasty (MLT) is generally
preferable to Argon Laser Trabeculoplasty (ALT) as they are less likely to result
in scarring of the trabecular meshwork and Schlemm’s (drainage) Canal.
Why, then, would anyone choose to have ALT?
Certain types of glaucoma may respond very well to ALT. Pigmentary glaucoma
is one of these. Of note is that eyes with heavily pigmented drainage angles
are more likely to have an IOP spike after SLT. Rarely such IOP elevations
have required non-laser surgery to control.[37] For these reasons, patients with
heavily pigmented angles may be better served by ALT than SLT.
37 Harasymowycz PJ, Papamatheakis DG, Latina M, et al. Selective laser trabeculoplasty (SLT) complicated
by intraocular pressure elevation in eyes with heavily pigmented trabecular meshworks. Am J Ophthalmol.
2005;139:1110-3.
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Additionally, up until just recently the SLT laser had a price tag in the USA
of about $70,000! Argon units, on the other hand, could be purchased for
between $20,000-40,000. Additionally, an Argon laser can be used for many
different types of eye treatment whereas an SLT laser is a “one trick pony”.
As you can imagine, not every eye surgeon could afford to place one of these
units in the office. Now, however, both SLT and MLT lasers can be purchased
for around $30,000-40,000. Although not an “impulse purchase”, a busy
glaucoma surgeon can now expect to be able to afford to pay down the price of
these units over a few years.
Summary
Laser Trabeculoplasty has a long track record of effectively lowering the
IOP while presenting relatively low risk to those receiving this treatment.
Selective Laser Trabeculoplasty has two key advantages over Argon Laser
Trabeculoplasty: (1) it is repeatable; (2) it is less likely to limit future glaucoma
surgical options such as the expanding number of available minimally invasive
glaucoma surgeries (MIGS).
Laser Trabeculoplasty works about as well as a single glaucoma drop. Given
the long-term side effects associated with chronic glaucoma drop use as well as
the cost of medications most patients with open angle glaucoma should at least
consider the option of SLT.
LASER
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SURGERY:
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LASER
TRABECULOPLASTY
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19
About Dr. David Richardson
Patient-focused Ophthalmologist,
Dr. David Richardson is a Board-certified Eye Doctor
in San Marino, California. He is a Magna cum laude
graduate of University of Southern California and a
multi-awarded Scholar of Harvard Medical School. His
patient-focused approach and commitment to providing
impeccable personalized care to his patients at all times
have earned him many awards from both patient-rated
and peer-rated award-giving bodies.
More about Dr. Richardson at
David-Richardson-MD.com
You may also contact Dr. David Richardson
at: (626) 289-7856