Selective vs argon laser trabeculoplasty:: hypotensive efficacy, anterior chamber inflammation, and postoperative pain

Purpose To compare selective laser trabeculoplasty (SLT) with conventional argon laser trabeculoplasty (ALT) in terms of hypotensive efficacy, anterior chamber inflammation, and pain reported by the patients treated. Methods A prospective study performed on 40 consecutive patients. Group I (n = 20): SLT 180degrees. Group II ( n = 20): ALT 180degrees. Intraocular pressure, flare (Laser-Flare-Meter, Kowa FM-500, Japan), and pain ( Visual Analogue Scale) were measured before treatment and 1 h, 24 h, 1 week, and 1, 3 and 6 months after treatment. Statistically significant differences were determined by an independent-sample Student's t-test. Results At 6 months after treatment, pressure reduction was similar in both groups: SLT 22.2% ( range 0 - 36.3%) and ALT 19.5% (range 0 - 30.2%), P = 0.741. The energy released during treatment was significantly lower in SLT (48.3 SD 7.4 mJ) than in ALT (4321 SD 241.7 mJ), P<0.001. At 1 h after treatment, anterior chamber flare was also lower in SLT (13.3 SD 6.3 vs 20.7 SD 7.4 photons/ms), P = 0.003. Pain reported by the patients during the treatment was significantly lower in SLT (2.0 SD 0.7 vs 4.3 SD 1.3), P<0.001. Conclusions The hypotensive efficacy of both lasers at the end of follow-up was similar. The energy released during treatment and inflammation produced in the anterior chamber in the immediate postoperative period were significantly lower for SLT. The SLT procedure was better tolerated, producing less discomfort during treatment than conventional trabeculoplasty with argon.