Argon and selective laser trabeculoplasty seem to induce similar IOP lowering effect.
Systematic review 1
The systemic review compare selective laser trabeculoplasty (SLT) to other glaucoma treatment options in terms of their intraocular pressure (IOP)-lowering effect. Searches performed on PubMed, Cochrane Central Register of Controlled Trials, Ovid, EMBASE, metaRegister of Controlled Trials, and ClinicalTrials.gov. Only randomised controlled trials (RCTs) were included. The main outcome measure was the change in IOP from baseline.
An initial search of PubMed identified 23 RCTs with 17 meeting the inclusion criteria. Nine RCTs compared 180degree SLT to 180degree argon laser trabeculoplasty (ALT) and one trial compared 360degree SLT to 360degree ALT, all reporting no difference in terms of IOP reduction from baseline. In terms of the IOP lowering effect, there was no difference between SLT and ALT «McAlinden C. Selective laser trabeculoplasty (SLT)...»1.
Systematic review 2
The purpose of the systematic review and meta-analysis was to evaluate the efficacy and tolerability of selective laser trabeculoplasty (SLT) and argon laser trabeculoplasty (ALT). Six clinic studies, all of which were random controlled trials, were selected through extensive searches of PubMed, Cochrane Library, Embase, and meeting abstracts. Efficacy measures were weighted by mean differences for intraocular pressure (IOP), as well as change of number of glaucoma medications and relative risks (RRs) for therapeutic IOP responses.
There was no significant difference in therapeutic IOP responses between SLT and ALT, with a pooled RR of 0.84 (95% CI, 0.51-1.38). When compared in patients with previous failed laser treatment (ALT or SLT), WMD was 1.48 (95% CI, 0.75-2.21). Patients who received SLT took fewer glaucoma medications after operations than those who received ALT, with a WMD of 0.29 (95% CI, 0.01-0.56). The frequencies of anterior chamber flare and IOP peak after operation were similar comparing SLT and ALT, with pooled RRs of 0.90 (95% CI, 0.74-1.11) and 0.90 (95% CI, 0.45-1.82), respectively «Wang H, Cheng JW, Wei RL ym. Meta-analysis of sele...»2
Six RCTS
Randomized controlled trials (RCTs) comparing SLT versus ALT were searched through August 2013. The main outcome measure was IOP, and secondary outcomes included the number of glaucoma medications, the success rate, and adverse events. Six RCTs, involving 482 eyes treated with laser trabeculoplasty, were included in the meta-analysis. For all patients (including first and previous laser trabeculoplasy), no significant difference in IOP lowering was observed between SLT and ALT at one hour (P = 0.40), one week (P = 0.72), one month (P = 0.37), six months (P = 0.08), one year (P = 0.34), two years (P = 0.58), three years (P = 0.34), four years (P = 0.47), and five years (P = 0.50). A statistically significant difference in favor of SLT was found when comparing the IOP reduction at three months after intervention (weighted mean difference (WMD): 1.19 mmHg [0.41; 1.97]; I(2)=0%; P = 0.003).
For patients who were naive to laser, there was no significant difference of reduction in IOP comparing SLT with ALT at any time point. In patients' previous LT, no statistically significant difference in IOP reduction was found at six months (WMD: 1.92 mmHg [-0.91; 4.74]; I(2) = 77.3%; P = 0.18). There was no significant difference in the reduction in the number of glaucoma medications, the success rate, or adverse event rates between the two treatments «Wang W, He M, Zhou M ym. Selective laser trabeculo...»3
Other references supporting the evidence «Rolim de Moura C, Paranhos A Jr, Wormald R. Laser ...»4, «Samples JR, Singh K, Lin SC ym. Laser trabeculopla...»5 ja «Damji KF, Bovell AM, Hodge WG ym. Selective laser ...»6