The Use of SLT in Secondary Open Angle Glaucomas ( PEXG, PDG)

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1 The Use of SLT in Secondary Open Angle Glaucomas ( PEXG, PDG) Prof. S. Melamed The Sam Rothberg Glaucoma Center Tel Aviv University Medical School Israel

2 Wear and Tear Glaucoma * Particulate Matter Glaucoma * EC Material in Trabecular Spaces and JCT blocking Aqueous Outflow * Trabecular cells are reduced in number, worn out, less phagocytic activity * Includes POAG, PEXG and PDG

3 PEX Glaucoma * A type of Elastosis * LOXL1 is defective, affecting Elastin formation * Fibrillar material is secreted by anterior segment organs, accumulating in JCT * MMP s activity is reduced * High Tension Glaucoma

4 Both ALT and SLT enhance Biological Activity of Trabecular Meshwork Outflow Facility is increased by: * Inducing Trabeculitis * Recruiting Macrophages * Enhancing Phagocytic Activity of TM cells * Increased Interleukins and Cytokines activity * Affecting Inner Wall of SC Tight Junctions and JCT Inner Wall Complex (Herniations)

5 Argon Laser Coagulation of TM

6 TEM 1 hr after ALT

7 TEM enhanced phagocytosis

8 4 weeks after ALT (monkey)

9 SEM - 4 weeks after ALT

10 ALT induced trabeculitis

11 ALT scarred lasered region

12 ALT non lasered region (ferritin)

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14 Histology of successful ALT Johnson 2007

15 Histology of successful ALT Johnson 2007

16 However, You do not need the Over-Kill of ALT in order to induce biological enhancement of the TM A more gentle Rx of Pigmented Cells alone will achieve similar effects!

17 SLT Selective Rx of Melanin containing trabecular cells only. * No coagulative necrosis * Induced synthesis of IL 1 alpha and beta * Recruitment of macrophages

18 SLT Biological and Physiological Studies (Alvarado, IGS, Athens, 2007) * Aqueous Outflow is increased after SLT * Laser Activated TM cells synthesize ligands which increase permeability of inner wall of SC * Media conditioned by SLT increases SC cells permeability when added to naive control

19 So, if ALT/SLT enhances TM biological activity All Wear and Tear Glaucomas should benefit most from Laser Trabecular Treatment However, not to much was published on ALT/SLT in PEXG and PDG

20 Accumulation of PXM on Anterior Lens Surface Scanning Electron Microscopy

21 TEM of PXM accumulating under inner wall of Schlemm s Canal From Richardson & Epstein, Ophthalmology 1981

22 ALT in PEXG Threlkeld et al, J Glaucoma, 1996 * 1 year failure rate : POAG 40% PEXG - 18% * 3 years failure rate : POAG 58% PEXG - 47% * Initial response to ALT in PEXG is greater, but long term outcome is similar to POAG

23 ALT in PEXG Sherwood & Svedberg, BJO, 1985 * 70% success after 15 months * 40% could reduce or stop Medical Rx * More early IOP spikes * Less Diurnal Curve Fluctuations

24 ALT in PEXG Higginbotham&Richardson BJO 86 * 360 degrees Rx * Better initial response to ALT in PEXG * Faster rate of long term failure than POAG

25 SLT Factors influencing success: Baseline IOP Only The higher the IOP at treatment, the greater the reduction Not related to: Age Sex Race Family history Other glaucoma risk factors Type & severity of OAG Trabecular meshwork pigmentation (unlike ALT) Pseudoexfoliation Number of glaucoma medications (unlike ALT) Previous ALT (unlike ALT) SLT as primary therapy Systemic Hypertension Diabetes Mellitus Hodge 2005; Nagar 2005; Chen 2004

26 SLT can be used to treat various forms of OAG Melamed Arch. Ophth. 2003;121:957 78% 64% SLT for PXF & POAG at 18 months no significant differences in: IOP reduction (31.4 vs. 35.1% ) Success rate ( 20% ) Gračner EJO 2002;12:287

27 SLT PDG & PEXG The amount of TM pigmentation was not a significant predictor of success [Hodge 2005] No race differences, but four of the six eyes with PDG and PXF failed to respond [Nagar 2005] PDG & PXF similar IOP reduction to POAG & OHT [Melamed 2003] No difference between results of PXF & PDG and other types, but TM pigmentation delayed IOP lowering [Chen 2004] However there are 6 case reports of paradoxical IOP rise [up to 20%] in heavily pigmented angles [Harasymowycz 2005; Van de Viere 2006] SLT can be used regardless of angle pigmentation, but there may be more complications in eyes with heavily pigmented trabeculum

28 SLT for PEXG Song et al.,j Glaucoma, 2007 * A retrospective study of 94 eyes * Failure definitions: less than 3 mm Hg or 20% IOP reduction * 86% to 92% failure after 14.5 months!!! * Average time to failure 6 months

29 Is there an advantage/disadvantage to SLT over ALT in PEXG or PDG? * A comparative study of ALT vs. SLT in PEXG is under way * Very few retrospective studies focusing on PEXG or with large number of patients have been reported

30 Why should we use SLT in PEXG or PDG? * Very impressive short term success in PEXG, with mid-long term success comparable to POAG * Safety of SLT allows Rx in elderly patients, minimizing side effects of drugs * Repeatability of SLT is an advantage * Use minimal energy in PDG or heavily pigmented TM to avoid IOP spikes * We need randomized prospective comparative studies