Laser trabeculoplasty: an investigation into factors that might influence outcomes.

OBJECTIVE: To examine the effectiveness of argon (ALT) or selective (SLT) laser trabeculoplasty (LTP) in lowering intraocular pressure (IOP) and to determine whether patient-related factors had any impact on outcome.

DESIGN: Retrospective review.

PARTICIPANTS: 500 patients treated with LTP over 14 years.

METHODS: This study was conducted at Sunnybrook Health Sciences Centre, University of Toronto. Five patient-related characteristics were used as dependent variables-age, race, gender, pseudophakic status, and pseudoexfoliation. IOP decrease and treatment failure at 12 months were the main outcome variables.

RESULTS: 500 eyes of 500 patients were included, 350 after ALT and 150 after SLT. The mean ± standard deviation baseline IOP was significantly higher in the patients treated by ALT than in those treated by SLT (24.2 ± 5.4 versus 22.2 ± 4.6, p < 0.0001) at baseline but not at 1 year (19.6 ± 5.1 versus 19.5 ± 6.1, p = 0.41). When the final IOP was examined by multiple regression analysis, there was a significant effect in favor of ALT over SLT (p = 0.03) and for patients with higher baseline IOPs (p < 0.0001). No significant effect was found for any of the demographic subgroupings. However, when the outcome variable was success or failure, only the baseline IOP remained significant.

CONCLUSIONS: Specific patient characteristics do not significantly influence LTP outcome after 12 months of follow-up. The most powerful predictor of either final IOP or clinical success was a higher baseline IOP, but ALT may have a better ability to lower IOP.