Comparative study of the efficacy of argon laser trabeculoplasty for exfoliation and primary open-angle glaucoma

Purpose: To investigate the efficacy of argon laser trabeculoplasty (ALT) for the treatment of primary open-angle glaucoma (POAG) and of glaucoma associated with exfoliation syndrome (EXF). Methods: Review of >200 charts from patients treated with ALT between 1981 and 1987 identified 66 POAG and 29 EXF eyes that underwent initial 180 degrees treatment. Variables including baseline intraocular pressure (IOP), age, sex, angle pigmentation, and follow-up IOP were studied with numerous statistical analyses. Multiple failure modes were used to define failure rate. All POAG and EXF patients were white. Results: The baseline pre-ALT IOP was 23.2 +/- 6.1 mm Hg for the POAG group and 25.8 +/- 5.9 mm Hg for the EXF group (p < .06). Mean follow-up time was 27 +/- 22 months for POAG eyes and 23 +/- 20 months for EXF eyes. Using failure mode 4 (glaucoma surgery, third laser, IOP less than or equal to 22 mm Hg, or two consecutive IOPs >85% of original baseline IOP), the 1-year failure rates were 40% (POAG) and 18% (EXF), and the 3-year rates were 58% (POAG) and 47% (EXF), p < 0.89) by log-rank test. A Cox proportional hazards model controlling for baseline IOP, age, sex, and angle pigmentation demonstrated that exfoliation status did not affect progression to filtering surgery (p > 0.60). Conclusion: Using multiple failure modes, the results suggest that the success rate of ALT in exfoliation glaucoma tends to decrease over time, but then stabilizes at this reduced value at a level similar to that of POAG. By 3 years, there is a substantial failure rate in both POAG eyes and EXF eyes. Although the initial response to ALT in EXF patients is greater, the long-term outcome is similar for both groups.