Randomized Clinical Study Results Comparing

1
Randomized Clinical Study Results Comparing
TitaniumSapphire and Argon Laser Trabeculoplasty
ARVO 5458
Gabriel Simon, MD PhD1, Shlomo Melamed, MD2,
Joseph A. Lowery, MSBE3 1Boston University
Biomedical Engineering, Boston, MA 2Goldschleger
Eye Institute, Sam Rothberg Glaucoma Center,
Tel-Hashomer, Israel 3SOLX, Inc., Boston, MA
This study has demonstrated that the 790nm
TitaniumSapphire Laser TST procedure provides
clinically significant IOP reduction of roughly
25 to 30 for up to 52 weeks following treatment.
This patient population continues to be
followed. These clinical results indicate that
TST offers a method for reducing IOP that is
equivalent to Argon Laser Trabeculoplasty. By
creating less thermal damage in the trabecular
meshwork, TST may allow the same areas of the
trabecular meshwork to receive treatment more
than once, unlike ALT which creates such a degree
of thermal damage in the tissues that repeating
treatment is not possible. Additional studies
will be useful to evaluate whether the IOP
reduction seen following TST allows the number of
glaucoma medications required by the patient to
be reduced.

• To compare intraocular pressure (IOP) reduction
  and clinical effect following laser
  trabeculoplasty with either a TitaniumSapphire
  laser or an argon laser in patients with primary
  open angle glaucoma (POAG).
• Argon Laser Trabeculoplasty (ALT) is an
  established clinical option for the treatment of
  open angle glaucoma by delivering laser energy to
  the trabecular meshwork to lower IOP. The
  procedure is well tolerated by the patient, and
  typically carries a low incidence rate of serious
  complications. ALT, however, can be performed
  only once on a given area of meshwork due to the
  destructive thermal nature of the treatment. An
  alternate method for performing laser
  trabeculoplasty may find a role in treating open
  angle glaucoma if it could demonstrate IOP
  lowering effect, few complications, and offer the
  ability to periodically repeat the treatment in
  an effort to delay surgical intervention, or
  reduce the patients dependence on glaucoma
  medication. TST may offer these benefits due to
  deeper trabecular meshwork penetration by the
  790nm wavelength, and less thermal damage
  following laser exposure.

83 eyes of 83 patients (n40 ALT n43 TST) were
enrolled in a 11 randomized, multi-center,
clinical trial to compare Argon Laser
Trabeculoplasty (ALT) treatment with
TitaniumSapphire Laser Trabeculoplasty (TST).
All patients were diagnosed as having open angle
glaucoma with uncontrolled IOP while on maximally
tolerated medication and having at least one
failed prior surgery. Treatment consisted of
50 laser exposures across 180 degrees of
trabecular meshwork. ALT treatment parameters
were selected by the surgeon to represent
standard clinical use. Typical ALT treatment
parameters used in this study were wavelength
488/514 nm pulse duration 200 ms, spot size 50
µm. For TST, the surgeon was instructed to use
the lowest possible treatment energy, typically
30 to 80 mJ, that achieved clinical endpoint,
defined as small vapor bubble formation, or
visible dispersion of debris from the trabecular
meshwork. Other TST treatment parameters were
fixed wavelength 790 nm, pulse duration 10 µs,
spot size 200 µm. Patients were scheduled
for follow-up visits at 1 day, and 1, 4, 13, 26
and 52 weeks after treatment.
The average IOP data for the two groups are shown
in the table and chart below.
IOP (mmHg) SD ALT TST Pre-Op
25.3 2.6 25.6 2.7 (n40 ALT 43 TST) 13
Week 19.3 3.3 19.5 3.5 (n32 33) 26
Week 18.5 3.3 20.2 3.9 (n28 25) 52
Week 20.2 4.6 18.1 3.7 (n14 14)
Both TST and ALT reduced IOP an average of 6 mmHg
(25) at the 13, 26 and 52 week follow-up visits
in this clinical trial. Complications were
infrequent and minor with both ALT and TST
treatment.
TitaniumSapphire Laser and Slit Lamp Delivery
System