Efficacy of 180 versus 360 Degrees of Selective Laser Trabeculoplasty on Lowering Intraocular Pressure
The purpose of this study was to determine if the application of 360° of selective laser trabeculoplasty (SLT) to the trabecular meshwork (TM) is more effective than 180° in the lowering of intraocular pressure (IOP) in glaucoma. This issue was addressed in the form of a retrospective chart review of patients treated consecutively with SLT for primary open angle glaucoma, pseudoexfoliation glaucoma or ocular hypertension. Patients were treated with either 180° of SLT by Dr. Wand or 360° by Dr. Martone using a 532nm, Q-switched, frequency doubled Nd:Yag laser. Only the initial treatment with SLT of a given eye was analyzed. There were 108 patients per group. Patient age, type of glaucoma, history of previous argon laser trabeculoplasty (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. Patients were classified as responders if the three month postoperative IOP was reduced by more than or equal to 3 mmHg compared to baseline.
At three months post-op the 360° group had a response rate of 60% and a mean IOP drop of 3.6 mmHg (17.8%). The 180° group had a response rate of 29% with a mean IOP drop of 1.5 mmHg (7.5%). The number of pre- and post-treatment medications, eye treated, gender, phakic status, number of spots delivered and pre-op IOP were equivalent for the two study groups. The 180° group subjects had more overall energy delivered during treatment and had had previous ALT more frequently than the 360° group. The 180° group also was significantly older and was less likely to have non-open angle glaucoma.
This study suggests that with a 2.1 mmHg greater drop in IOP and 31% greater response rate at three months post-op 360 degrees of SLT is more effective in lowering intraocular pressure than 180 degrees.
School Location:USA - Connecticut
Source Type:Master's Thesis
Keywords:laser therapy trabeculectomy intraocular pressure glaucoma ophthalmology
Date of Publication:03/04/2008