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Specifics of Anterior Segment LASER PROCEDURES A.L.T. S.L.T. ALONE AND IN COMBINATION

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Specifics of Anterior Segment LASER PROCEDURES A.L.T. S.L.T. ALONE AND IN COMBINATION

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    1. Specifics of Anterior Segment LASER PROCEDURES A.L.T. & S.L.T. ALONE AND IN COMBINATION Leland Carr, O.D. Oklahoma College of Optometry Northeastern State University CarrLW@nsuok.edu

    2. Thermal Laser Trabeculoplasty Indications: OPEN ANGLE Glaucomas Must be able to “see” the angle

    3. Trabeculoplasty is appropriate for: Primary Open-angle glaucoma Pigmentary Glaucoma Pseudoexfoliative Glaucoma Normal Tension Glaucoma Angle-recession Glaucoma

    4. Trabeculoplasty may be appropriate for ANGLE RECESSION GLAUCOMA A.L.T. Apply treatment to NON-recessed angle S.L.T. Apply treatment to NON-recessed angle

    5. NSU-OCO Study Apply SLT to 360-degrees following Angle Recession---prior to development of ANGLE CLOSURE GLAUCOMA ?????

    6. Trabeculoplasty is NOT appropriate for: Primary Closed-angle Glaucomas Secondary Closed-angle Glaucomas Inflammatory Glaucomas Neovascular Glaucomas

    7. S.L.T. may be appropriate in the management of Primary Angle Closure Glaucoma Southeast Asian Study (6 centers) 50 patients Chronic Angle Closure Glaucoma (“combined mechanism glaucoma”) Dual Laser Therapy Peripheral Iridotomy S.L.T.

    8. Mechanism(s) of action Mechanical Effects Photobiostimulatory Effects

    9. Laser//Tissue Interaction A.L.T. “thermal process” MECHANICAL EFFECT Laser energy converted to heat following absorption by melanin Significant peripheral heat-spread S.L.T. “non thermal” BIOSTIMULATORY EFFECT Energy delivery is small and brief Only 1% the effective energy associated with A.L.T. Energy absorbed very locally by melanin containing cells No heat build-up to thermal relaxation time of melanin

    10. A.L.T.’s impact on meshwork

    11. S.L.T.’s impact on meshwork

    12. Anecdotal Reports: “A.L.T. doesn’t work as well on pseudophakes as it does on phakic patients.” “S.L.T. seems to work equally well on phakic, aphakic, and pseudophakic patients.”

    13. A.L.T. Performing Argon Laser Trabeculoplasy

    14. Perform Gonioscopy Obtain Informed Consent Instill 1 gt. Iopidine or 1 gt. Alphagan-P (rarely) Instill 1 gt. 1-2% Pilocarpine

    15. Performance of A.L.T. Treat 180 or 360 degrees? 50 – micron spot (argon) Approximately 60 burns per 180 degrees Apply to anterior ˝ of meshwork

    16. Obtain “blanching” to whitening of tissue (adjust Power setting to obtain it) Avoid “charcoaling” Avoid “bubbling” Avoid “blistering”

    17. Or……Just make it easy! Set power at 1000 mWatts

    18. Post-op Instill 1 gt Iopidine or 1 gt Alphagan-P Rx: PredForte 1 gt. q.i.d. Rx: Continue all pretreatment glaucoma medications Including Prostamides! If not currently using Mx, go with Alphagan-P 1 gt t.i.d. ? Recheck patient at 1 week

    19. Most often do LOWER angle first Most often do NOT retreat upon previously-treated meshwork! 60% will benefit in terms of new IOP lowering 40% will NOT benefit, and will often respond with a rise in IOP

    20. Be Patient……. Need to wait for 4-6 weeks to assess efficacy of A.L.T.

    21. Followup Continue ALL pre – treatment glaucoma medications, but consider tapering if ALT results warrant Use Pred – forte to control iritis, only as needed Avoid judging the effects for 4 – 6 weeks Recheck adequacy of control each 3 months Especially likely to “drift” first two years

    22. S.L.T. Selective (wavelength) Laser Trabculoplasty For Open Angle Forms of Glaucoma

    23. S.L.T. Basics Q-switched, Frequency-doubled Nd:YAG Laser System Outputs 532 nm emission Brief 3 nsec pulse “Low Power” (Energy) burns Targets Pigmented Trabecular Meshwork Cells Minimal “peripheral damage” to non-pigmented cells and/or collagen

    24. Laser Trabeculoplasties; SPOT SIZES ARGON procedures: 50 microns DIODE procedures: 60 microns S.L.T. procedures : 400 microns

    26. How is it working? “Gentle mechanical effect” (minor) Reshaping meshwork anatomy and mechanics Less dramatic than the A.L.T. effect “Biostimulatory effect” (major) Increased cellular metabolism Increased cellular mitosis

    27. “Enhanced Housekeeping” Stimulate macrophages Release cytokines Remove metalloproteases

    29. S.L.T. Performing Selective Wavelength Laser Trabeculoplasy

    30. Discontinue all glaucoma medications 1-2 weeks prior to S.L.T. (?????) Ellex SLT website Mrs. Madhu Nagar “I prefer to discontinue all glaucoma medications prior to SLT, rather than post SLT. The higher the baseline IOP, the greater the IOP reduction.”

    31. Perform Gonioscopy Obtain Informed Consent Instill 1 gt. Iopidine or 1 gt. Alphagan-P (rarely) Instill 1 gt. 1-2% Pilocarpine

    32. S.L.T. Treatment Parameters Wavelength: 532 nm Pulse: 3 nsec Spot: 400 microns Energy per pulse: .6 to 1.2 mJoules Shots: 45-55 “adjacent” Location: inferior or nasal 180-degrees

    33. Laser Lens Goldman 3-Mirror A.L.T. Trabeculoplasty Lens Better to NOT use a Diode Trabeculoplasty Lens

    34. Titrate the Energy Setting Start with around .6 mJoules Gradually increase setting to produce a visible “steam” of micro-bubbles upon firing the laser (viewed through the slit-lamp and laser lens)

    35. Or……Just make it easy! Set energy at 1.0mJ

    36. Best to Avoid the 11:00 – 1:00 Zone? Better to leave the meshwork “virgin” in the area where a filtering procedure might need to enter the angle? Also Consider: The Advanced Glaucoma Intervention Study indicated that African-American patients have better surgical outcomes when A.L.T. is done prior to a filtering procedure

    37. Treat 180 or Treat 360 Degrees 180 advocates Less risk of a laser-induced IOP spike (Perhaps) advisable for Pigmentary and Pseudoexfoliative Glaucoma patients 360 advocates (Perhaps) greater IOP reduction (Perhaps) longer duration of efficacy

    38. Post-Procedure Don’t use steroids unless an intense iritis occurs Expect to see pigment immediately post-op Use Topical and Systemic Non-Steroidals Acular, Nevanac, Voltaren (1 drop 4-5 times daily) Ibuprofen (two 200mg tables 4 x daily) Treat for 3-4 days

    39. Don’t try to judge the efficacy for at least a month, and 6-8 weeks is really a better time for assessment of treatment success

    40. OUTCOMES Expect all patients will require at LEAST two separate treatments to produce a maximal effect! Best to wait at least 6 weeks before doing the second (and subsequent) treatments Works on over 70% of treated eyes Expect a 22% to 28% reduction from pre-treatment IOP

    41. When to retreat/repeat SLT? As soon as pressure starts rising again. No harm done by waiting until IOP surpasses target IOP…..but why wait?

    42. Medicare Exclusion: 10 Days And you really want to wait for at least 6 weeks prior to a retreatment, anyway!

    43. Outcomes Most often effects last a least one year Average SLT “usefulness” is 3 years Do expect some loss of efficacy over time S.L.T. is repeatable S.L.T. can be safely performed on patients who have previously had Argon or Diode trabeculoplasties

    44. COMBINATION ALT/SLT Perform standard A.L.T. As “drift” becomes apparent, re-treat the meshwork using S.L.T. Some experts consider that A.L.T. pressure-lowering can be enhanced using immediate S.L.T. follow-up treatments Maximal mechanical impact Maximal biostimulatory impact

    45. S.L.T. can be tried on “failed” A.L.T. cases Studies have shown that up to 80% of “A.L.T. failures” can be successfully treated with S.L.T. Typical IOP reduction is approximately 22% from pre-S.L.T. baseline

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