Laser
Trabeculoplasty for Reducing Intraocular
Pressure
(IOP) with a Titanium:Sapphire 790nm Laser
Gabriel
Simon, MD, PhD1, Joseph A. Lowery, MSBE, MBA2,
Jason Clevenger, MSBE2
1Boston University Biomedical
Engineering, Boston, MA; 2SOLX, Inc., Boston, MA
In the randomized study, 40 patients
were treated with ALT, and 43 with TLT.
Average pre-treatment IOP was 26.6 + 3.8 mmHg for the TLT group; 24.9 + 3.1 for ALT group. At 26
weeks the average IOPs were 20.2 +
3.9 for TLT (n=25); 18.5 + 3.3 for ALT (n=28). At 52 weeks the average IOPs were 18.1 + 3.7 for TLT (n=14); 20.2 + 4.6 for ALT (n=14).
Results
The 790 nm Titanium:Sapphire Laser
provides clinically significant reduction of IOP, roughly 6 mmHg at 3, 6 and
12 months; and has demonstrated at least equivalence to Argon Laser
Trabeculoplasty in our clinical trial out to one year. Complications with both lasers were minor
and infrequent.
The IOP lowering effect of the
Titanium:Sapphire laser was further substantiated in our much larger study of
337 patients, demonstrating a clinical benefit of about 5 to 6 mmHg at 3, 6
and 12 months post-Tx.
The less thermal nature of the laser
exposure with TLT, however, could allow for eventual re-treatment of the same
areas on the trabecular meshwork --- unlike ALT which induces a high degree of
thermal damage that re-treatment is not possible.
Conclusions
Future studies would be useful for
evaluating the ability of the Titanium:Sapphire laser to be administered in a
repeatable fashion as needed to control IOP, and delay the need for surgical
intervention for glaucoma. Additional
studies would be useful for evaluating whether the IOP reduction seen
following Titanium:Sapphire laser treatment may allow patients to reduce the
number of glaucoma medications they need.
Future Implications
Methods
Two clinical studies were initiated
to investigate laser trabeculoplasty with a flashlamp-excited, pulsed
Titanium:Sapphire laser operating at a wavelength of 790 nm in the
near-infrared spectrum. The laser was
delivered gonioscopically with a slit lamp at energies of 30 to 60 mJ, spot
size 200 micron, and pulse duration of 10 microsceconds.
Objective
To evaluate the clinical efficacy of
a 790nm, solid-state Titanium:Sapphire laser for performing laser
trabeculoplasty as a method of lowering intraocular pressures (IOP) as a
treatment for open angle glaucoma.
Background
Laser Trabeculoplasty is an
established clinical option for the treatment of open angle glaucoma using
first argon, and more recently other laser systems. The procedure provides the clinician with a
non-invasive method of delivering light to the trabecular meshwork to lower
the intraocular pressure, is generally well tolerated by the patient., and
typically carries a low incidence rate of serious complications due to
treatment. An alternate method for
performing laser trabeculoplasty may find a role in treating open angle
glaucoma if it could demonstrate IOP lowering effect, fewer complications,
offer the ability to periodically repeat the treatment in an effort to delay
surgical intervention, or possibly reduce the patient’s dependence on glaucoma
medication. We present here the results
of clinical trials which investigate a Titanium:Sapphire for this role.
This research was supported by SOLX,
Inc. Device approved for sale in Europe and Canada. Investigational in United States.
Disclosures
Methods (continued)
The lowest possible treatment energy
was used that achieved clinical endpoint, defined as small vapor bubble
formation, or visible dispersion of debris from the trabecular meshwork. Two clinical studies with the Titanium:Sapphire
have been followed. All patients provided informed consent, and all study
protocols were approved by IRB.
For the first study, 83 patients
were enrolled as part of an approved protocol for a randomized, clinical trial
comparing Argon Laser Trabeculoplasty (ALT) to Titanium:Sapphire Laser
Trabeculoplasty (TLT). All patients in
this group were diagnosed with open angle glaucoma, with uncontrolled IOP
while on maximally tolerated medication.
Patient were treated and were followed to 52 weeks.
A second study was initiated to
evaluate TLT only at clinical sites where CE approval has been attained. A total of 337 patients were enrolled and
followed to 12 months.
Figure One:
Titanium:Sapphire
Laser and Slit Lamp Delivery System
TLT EXCLUSIVE STUDY:
In the larger, TLT exclusive study, 337 patients were selected for treatment with TLT. Average pre-treatment IOP was 22.7 + 5.1 mmHg. Subsequent average IOP (mmHg) readings were:
In the larger, TLT exclusive study, 337 patients were selected for treatment with TLT. Average pre-treatment IOP was 22.7 + 5.1 mmHg. Subsequent average IOP (mmHg) readings were: