Selective Laser Trabeculoplasty (SLT) Effectiveness in Eyes Pretreated With Argon Laser Trabeculoplasty (ALT)

Aim: To compare the effectiveness of SLT in patients who had a previous ALT treatment with patients without a history of ALT., Materials and Methods: 208 eyes of 166 patients were divided into 3 major groups according to having a previous ALT treatment or not. Group A: no previous ALT, Group B: previous 180 degrees ALT, Group C: previous 360 degrees ALT. The major groups, then re-categorized according to the quadrantal relationship of the previous ALT and recent SLT procedures. Statistical evaluations were done by using ANOVA and t-tests. Results: Within the major groupings, A, B and C are similar in mean follow- up and in baseline TOP. However they differ in the mean change in IOP, that being -5.5, -4.4 and -3.5 mmHg respectively. Conclusion: Although the differences between treatment groups are not statistically significant, we conclude that SLT is effective in patients who had been treated by ALT, but the effect of SLT is inversely proportional to the range of the area previously treated by ALT.