Selective Laser Trabeculoplasty Selective Laser Trabeculoplasty SLT - PowerPoint PPT Presentation

Selective Laser Trabeculoplasty Selective Laser Trabeculoplasty “SLT SLT” ” “ Jorge L. Fernandez- -Bahamonde, M.D. Bahamonde, M.D. Jorge L. Fernandez

Background and Rationale for laser therapy Background and Rationale for laser therapy in Glaucoma. in Glaucoma. • Compliance with therapy is poor for chronic diseases. – 20% or less follow adequate dosage regime. • Pressure spikes may be partially responsible for further optic nerve deterioration. • In severe disease goals are hard to achieve with medical therapy only. – IOP never above 18 mm Hg. – Average below 14 mm Hg.

Background and Rationale for laser Background and Rationale for laser therapy in Glaucoma. therapy in Glaucoma. • Lasers have a long history of use in the management of glaucoma • ALT was initially utilized in patients who failed medical therapy • The Glaucoma Laser Trial (GLT) established efficacy of ALT in lowering IOP in previously untreated primary open-angle glaucoma patients

Background and Rationale for laser Background and Rationale for laser therapy in Glaucoma. therapy in Glaucoma. Glaucoma Laser Trial • 271 patients with previously untreated primary open angle glaucoma randomized to ALT or medication • Through 2-year follow-up, ALT eyes had lower intraocular pressure (IOP) than medication-treated eyes. – 25% did not require Rx • At 7 years, ALT-treated eyes: – lower IOP – better visual field and optic disc appearance.

Why SLT? Why SLT? • Limitations of argon laser trabeculoplasty (ALT) ♦ Post-treatment increase in IOP; PAS ♦ Limited efficacy of ALT re-treatment ♦ Coagulative damage to the trabecular meshwork (TM) • Selective laser trabeculoplasty (SLT) is developed as an alternative to ALT

Selective Laser Trabeculoplasty Selective Laser Trabeculoplasty “SLT SLT” ” “ • Q-Switched frequency doubled (532 nm) Nd:YAG Laser – Selecta 7000 Glaucoma Laser System*. • Permits selective targeting of pigmented trabecular meshwork (TM) cells without causing structural or coagulative damage to the TM *Lumenis, formerly Coherent

Selective Laser Trabeculoplasty Selective Laser Trabeculoplasty Latina et al. Latina et al. • Selective Photothermolysis – Requirements • Intracellular target chromophore (melanin) and no competing chromophores • Targets must absorb laser energy better than surrounding tissues • Short Laser Pulse to generate and confine heat – Only pigmented cells within the irradiation zone will be targeted

Selectivity Selectivity • Confine heat diffusion spatially by limiting the applied light pulse duration below the thermal relaxation time of the target.

Laser and the TM. Laser and the TM. • TM cells are phagocytic and contain variable amounts of melanin • ALT induces focal scarring and coagulative damage with reduced flow through the laser-treated site. – Non-repeatable.

TM Cell Culture Fluorescence TM Cell Culture Fluorescence Live/Cytotoxicity Cytotoxicity Microscopy Microscopy - - SLT SLT Live/

Structural changes ALT vs. SLT. Structural changes ALT vs. SLT. Human TM. Human TM. ALT 50 um spot SLT 400 um spot.

Selective Targeting of TM Cells Selective Targeting of TM Cells In Vitro Studies. In Vitro Studies. • Pigmented TM cells can be selectively targeted without damage to adjacent non-pigmented cells • Optimal laser is a Q-switched Frequency Doubled 532 nm Nd:YAG laser (3 nsec pulse)

Comparison of Lasers Q-switched 1064 nm Nd:YAG (7970) Diode - LTP or 810 nm cyclophoto 532-green LTP SLT 532 nm Argon LTP 514 nm CW (0.1 sec) 3 nsec Pulse Duration M. Latina, M.D

Comparison of SLT vs vs ALT ALT Comparison of SLT SLT ALT Ratio No. of spots 50 50 Energy 0.8-1.4 mj 400-600mw 1:100 2 ) Fluence (mj/mm 6 40,000 1:6000 Exposure Time 3 nsec 0.1 sec

Courtesy M. Berlin, M.D. ALT spot vs. SLT spot size

Courtesy M. Berlin, M.D. SLT vs. ALT Treatment

Spot Size Comparison Spot Size Comparison (dia. =10 um) SLT spot size 1064 nm q-sw Nd:YAG (dia. = 400 um)

Selective Laser Trabeculoplasty Selective Laser Trabeculoplasty FDA Clinical Results Summary. FDA Clinical Results Summary. • Both U.S. and Canadian data sets show comparable SLT- related IOP lowering effects, response rates and safety profiles. – Canadian data now to 2 years with comparable results. 0 e y k s s s s s s n a k k k k k k w -2 i d l w w w w w w e 1 1 4 s 2 8 4 0 6 IOP (mmHg) a 1 2 2 b -4 -6 -8 -10 Weeks Max Rx Group PFLT Group Combined

Selective Laser Trabeculoplasty Selective Laser Trabeculoplasty FDA Clinical Results Summary. FDA Clinical Results Summary. • 70% of patients [uncontrolled OAG on Max. Rx and prior failed laser trabeculoplasty (PFLT)] respond with > 3mmHg drop in IOP • Average, sustained IOP drop 6.0 + mmHg or 25%. • Over 2000 patients have been treated and followed for as long as two years in numerous international studies with similar results.

SLT Study Designs for FDA SLT Study Designs for FDA U.S. - Historical Control MaxRx PFLT SLT SLT Canada - Prospective Randomized MaxRx PFLT SLT SLT ALT ALT

Objectives. Objectives. US Study. Canadian Study. Safety and effectiveness of Compare SLT with ALT in SLT to reduce IOP in treatment of patients with patients with open-angle open angle glaucoma. glaucoma.

SLT – Treatment Parameters SLT – – Treatment Parameters Treatment Parameters SLT Wavelength - 532 nm Pulse duration - 3 ns Spot size - 400 µm Energy / pulse - 0.6-1.2 mJ 2 Fluence - 600 mJ / cm Spots - 45-55 confluent inferior or nasal 180 Lens - Goldmann 3 mirror

Selective Laser Trabeculoplasty Selective Laser Trabeculoplasty Patient Demographics (US) (US) Patient Demographics • 120 patients treated – 65 females (54.2%) – 55 males (45.8%) – Mean Age 67.7 yrs (ages 29-90 yrs) - 77 (64.2%) Caucasians - 34 (28.3 %) African-Americans - 9 (7.5%) Hispanics - 0 Asians

Selective Laser Trabeculoplasty Diagnosis - 120 patients enrolled • POAG 99 (82.5%) PXF 7 (5.8%) Pigmentary 7 (5.8%) Mixed Mec. 5 (4.2%) Pseudophakia 3 (2.5%) Juvenile 1 (0.8%)

Trabecular Pigmentation Trabecular Pigmentation • Graded on Scale of 1- 4+ – 1+ pigmentation - 35.6% – 2+ pigmentation - 37.3% – No difference between eyes or treatment groups

Selective Laser Trabeculoplasty Treated vs. Untreated Eyes All eyes (120) at 26 wks f/u Δ Pre-op Post-op % drop p value IOP IOP IOP (mm Hg) (mm Hg) SLT 25.3 20.9 <.001 Treated -4.4 17.1% Eye 21.4 19.5 -1.9 8.3% <.001 Untreated Eye P-value Difference (treated vs. untreated) <.003

SLT-Treated Eyes Mean IOP Reductions at 26 weeks Intent-to-Treat Analysis (120 patients) No. of Pre-op Mean % IOP P Δ IOP Eyes Drop IOP Value (mm Hg) ( mm Hg) Max Rx 25.3 53 (44%) -5.1 20.0 <0.001 PLTP 67 (56%) 25.3 -3.8 14.7 <0.001 Combined 120 (100%) 25.3 -4.4 17.1 <0.001

SLT- -Treated Eyes Treated Eyes SLT Mean IOP Reductions at 26 weeks Mean IOP Reductions at 26 weeks Responders (> > 3 mm Hg IOP reduction) 3 mm Hg IOP reduction) - - 71/101 eyes 71/101 eyes Responders ( No. of Pre-op Mean % IOP P Δ IOP Eyes Drop IOP Value ( mm Hg) (mm Hg) All 25.5 71 (70%) Responders -6.0 23.6 <0.001 34 (76%) MaxRx 25.3 -6.5 25.3 <0.001 37 (66%) PLTP 25.6 -5.7 22.1 <0.001

Selective Laser Trabeculoplasty Selective Laser Trabeculoplasty Adverse Events - - 120 eyes 120 eyes Adverse Events MaxRx PLTP Combined group group No. of Subjects 53 67 120 Event A/C Inflammation 47 (89%) 60 (90%) 107 (89%) Pain/Discomfort 1 (2%) 5 (8%) 6 (5%) Redness 2 (4%) 4 (6%) 6 (5%) IOP Elevation (within 2 hrs post-op) > 10 mm Hg 3 (2.5%) 4 (3%) 7 (6%)

Post- -op Ocular Characteristics op Ocular Characteristics Post • Peripheral Anterior Synechiae – None considered to be related to the study device or treatment • treated eye - 8 patients (6.7%) • 1 MaxRx • 7 PLTP • non-treated eye - 7 patients (5.8%) • No relation between TM pigmentation and IOP reduction

Selective Laser Trabeculoplasty Conclusions (US). • A safe and effective treatment to lower IOP in patients with open angle glaucoma. • IOP reduction has been maintained for up to 26 weeks in this clinical trial • International studies show IOP reductions of 22%-28% with 36-49 weeks follow-up • Effective in patients with prior ALT with uncontrolled IOP. • Response similar to MaxRx Group.

Baseline Characteristics Baseline Characteristics Total Study Population (n=77) Total Study Population (n=77) Canadian Study. Canadian Study. ALT Group SLT Group P-value (n=42) (n=35) Age (mean, in years) 70.1 66.2 0.10 (SD 10.2) (SD 10.4) Diagnosis 0.50 POAG 25 (59.5%) 20 (57.1%) Pseudoexfoliative 12 (28.6%) 7 (20.0%) Pigmentary 1 (2.4%) 3 (8.6%) Other 4 (9.5%) 5 (14.3%) IOP (mean,SD - mmHg) 23.6 (3.5) 23.6 (4.1) 0.99 K. Damjii, et al