Abstract
Purpose: :
To compare 360 degrees selective laser trabeculoplasty (SLT) to 180 degrees in the lowering of intraocular pressure in glaucoma. Design: Retrospective chart review.
Methods: :
The charts of consecutive patients with primary open angle glaucoma or pseudoexfoliation glaucoma treated with SLT were reviewed. Only the initial treatment with SLT of a given eye was analyzed. Patients were treated with an average of 100 applications over 180 degrees (MW) or 360 degrees (JFM) using a 532nm, Q–switched, frequency doubled Nd:Yag laser. Patient age, type of glaucoma, history of previous ALT, number of medications, lens status and visual acuity pre–and post–treatment and the number and power of laser spots were compared between the treatment groups. The mean IOP from three consecutive visits prior to treatment was compared with post–operative IOPs measured at 1 hour, 6 weeks, and 3 months. Post–op IOPs were compared between the two groups at these time points as well. Patients were classified as responders if the three month postoperative IOP was reduced by more than or equal to 3 mmHg compared to baseline.
Results: :
There were 108 patients per group. At three months post–op the 360 degrees group had a response rate of 61% and a mean IOP drop of 3.6 mmHg (18.7%) ( P<0.001, CI 2.9 to 4.3). The 180 degrees group had a response rate of 29% with a mean IOP drop of 1.4 mmHg (7.6%) (P=0.001, CI 0.64 to 2.21). The 2.2 mmHg greater drop in IOP in the 360 degrees group at three months was statistically significant (P<0.001, CI 1.14 to 3.24). The number of pre– and post–treatment medications, age, phakic status, number of spots delivered and pre–op IOP were equivalent for the two study groups.
Conclusions: :
In this study, the 360 degrees SLT group experienced a higher response rate than the 180 degrees group. With a 2.2 mmHg greater drop in IOP and 32% greater response rate at three months post–op 360 degrees of SLT is more effective in lowering intraocular pressure than 180 degrees.
Keywords: laser • intraocular pressure • trabecular meshwork