[Pressure reduction after selective laser trabeculoplasty with two different laser systems and after argon laser trabeculoplasty--a controlled prospective clinical trial on 284 eyes].
BACKGROUND
Selective laser trabeculoplasty (SLT) is a new method to reduce intraocular pressure in eyes with primary open angle glaucoma. The laser parameters of a Q-switched, frequency-doubled Nd:YAG-laser are set to selectively target pigmented trabecular meshwork cells without visible damage to the adjacent non-pigmented tissue. SLT acts non-thermally, the intracellular microdisruptions triggered by the laser are confined to the targeted cells, the laser pulses are so short that heat caused within the targeted cells does not have time to spread to the surrounding tissue. A controlled prospective randomised clinical study was conducted to compare the long-term results, safety and efficacy after SLT with two different laser systems and after ALT in the treatment of ocular hypertension and medically uncontrolled open angle glaucoma.


METHODS
About two years ago the authors performed a selective laser trabeculoplasty in 119 eyes using the SLT laser unit Otello (Glautec AG, ARC, EC), here named as SLT-I, and in 124 eyes using the SLT laser unit Selecta II (Lumenis, Palo Alto, CA), here named as SLT-II. In 41 eyes the authors performed argon laser trabeculoplasties using the argon laser Argus (Aesculap Meditec, EC).


RESULTS
Two months after treatment mean IOP reduction from baseline was 1.9 mmHg or, respectively, 8.8 % after SLT with the SLT-System I, 2.0 mmHg or, respectively, 9.5 % after SLT with SLT-System II, and 2.2 mmHg or, respectively, 9.9 % after ALT with the argon laser. Twelve months after LTP mean pressure reductions were 1.7 mmHg (7.9 %) after SLT-I, 1.8 mmHg (8.5 %) after SLT-II, and 2.1 mmHg (9.4 %) after ALT. The response curve of the eyes with SLT-I greatly resembled that of the eyes with SLT-II and those eyes with ALT.


CONCLUSIONS
Pressure reduction was highest after ALT, followed by SLT-II, in SLT-I reduction was the least, but the differences were not significant. Our findings did not correspond with those of other authors reporting an average IOP reduction of 25 % after SLT and ALT. SLT has shown reasonable efficacy in lowering IOP in eyes with ocular hypertension and primary open angle glaucoma, SLT achieves about the same level of IOP reduction compared with ALT. As a result of the preservation of the structure of the trabecular meshwork and low rate of complications, SLT is a safe alternative to ALT. The exact biological effect induced with SLT is still not yet understood. For the early glaucoma stages SLT provides an alternative to drug treatment, for the advanced glaucomas SLT is an additional option for further pressure reduction. More long-term follow-up studies are needed to determine whether the IOP lowering effect is sustained over time, and to assess the efficacy of repeated SLT.
Best
U-P
UP
Augenklinik und Augenlaserklinik Mainfranken. UPBest@t-online.de
Domack
H
H
Schmidt
V
V
D001128:Argon; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005901:Glaucoma / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure; D053685:Laser Therapy / Q000295:instrumentation* / Q000379:methods; D009798:Ocular Hypertension / Q000175:diagnosis / Q000601:surgery*; D011446:Prospective Studies; D014130:Trabeculectomy / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome
D001128:Argon