1. EFFECT OF CORNEAL THICKNESS ON SELECTIVE LASER TRABECULOPLASTY
Kristina E. Fittipaldi, BA
Elaine M. Miglino
Arusha Gupta, MD
Lawrence F. Jindra, MD

2. Financial Disclosures
1st, 2nd, and 3rd authors have no financial disclosure. 4th author has independently conducted and financed clinical research study presented and provides technical advice and consultant services to Lumenis Corporation. 2

3. Introduction
Selective Laser Trabeculoplasty (SLT) uses a Q-Switched frequency-doubled (532 nm) Nd:YAG laser which targets melanocytes in the pigmented trabecular meshwork.1,2 When treated with SLT, a primarily biologic response is induced in the trabecular meshwork which involves the release of cytokines that trigger macrophage recruitment and other changes leading to IOP reduction.2 It treats the meshwork without causing any thermal or coagulative damage to surrounding structures.1,2
1. Latina MA, et al. Selective targeting of trabecular meshwork cells: in vitro studies of pulsed and cw laser interactions. Exp Eye Res. 1995;60: Latina MA, et al. Q-switched 532-nm Nd:YAG laser trabeculoplasty (selective laser trabeculoplasty): a multicenter, pilot, clinical study. Ophthalmology. 1998;105: 3

4. Objective & Methods
To examine the effectiveness of SLT in decreasing intraocular pressure (IOP) in glaucoma patients with thin (<525 µm), average ( µm), and thick (>575 µm) corneas.
A retrospective chart review was performed on 1376 eyes divided into 3 categories based on corneal thickness, in a consecutive case series from patients treated with SLT between 2002 and Two-tailed paired t-test was used for each category to compare pre- and post-SLT IOP.

5. Results: Thin Corneal Group
254 eyes with thin corneas (mean thickness 500 µm) received SLT as treatment for glaucoma.
IOP decreased from a mean of 18.4 mm Hg ± 5.1 to 14.4 mm Hg ± This represents a 22% decrease in IOP or 4.0 mm Hg.
Data were significant with P < 0.01.

6. Results: Average Corneal Group
560 eyes with average corneas (mean thickness 551 µm) received SLT as treatment for glaucoma.
IOP decreased from a mean of 19.4 mm Hg ± 5.2 to 14.3 mm Hg ± 4.7. This represents a 26% decrease in IOP or 5.1 mm Hg.
Data were significant with P < 0.01.

7. Results: Thick Corneal Group
562 eyes with thick corneas (mean thickness 622 µm) received SLT as treatment for glaucoma.
IOP decreased from a mean of 19.7 mm Hg ± 4.9 to 14.6 mm Hg ± 4.3. This represents a 26% decrease in IOP or 5.1 mm Hg.
Data were significant with P < 0.01.

8. Data Corneal Group Thin Average Thick 254 560 562 500 551 622 18.4
Number of eyes (n)
254
560
562
Mean thickness (m)
500
551
622
Pre-SLT IOP (mm Hg)
18.4
19.4
19.7
Post-SLT IOP (mm Hg)
14.4
14.3
14.6
IOP change (mm Hg)
4.0
5.1
%  IOP 22 26
P-value
< 0.01

9. Results

10. Summary Mean Post-SLT Reduction in IOP: Thin corneas 22%
Average corneas 26%
Thick corneas 26%
The results were significant with P < 0.01.

11. Conclusion
In this clinical series, SLT significantly lowered intraocular pressure in patients with thin, average, and thick corneas, when used as a treatment for glaucoma.