Abstract
Purpose: :
To evaluate the response to selective laser trabeculoplasty (SLT) across a range of total energy (TE) laser intensities in patients with poorly controlled open angle glaucoma (OAG) while ocular drug therapy was held constant over a 1 year period.
Methods: :
A retrospective chart review was performed to evaluate the effect of SLT at different levels of laser TE on intraocular pressure (IOP) in consecutively treated patients with OAG while receiving fixed ocular drug therapy. For each patient, single session SLT 3600 was performed by one of two glaucoma specialists to augment IOP control in patients not achieving target IOP despite medical therapy. The first eye receiving SLT was included for analysis. Baseline IOP was defined as the average IOP on 3 visits on fixed ocular drug therapy prior to SLT treatment. A total of 43 eyes met inclusion criteria and were followed for up to 1 year with a minimum of 3 post-treatment IOP measurements. Laser TE of the SLT session was recorded and serial IOP measurements were used to construct a dose-response function.
Results: :
We studied 43 patients with a mean age of 72.6 years, 32 were phakic and 11 pseudophakic, taking an average of 2.2 glaucoma medications. The average TE utilized for SLT was 116.46 mJ with a range from 63.9 mJ to 207.1 mJ and an average of 97.65 (71-110) shots. The average pre-treatment IOP was 17.8 mmHg, and the average post-treatment IOP was 15.4 mmHg. A two-factor repeated measures analysis of variance was used to assess the effects of TE on post-treatment IOP. The analysis showed that SLT produced a significant decrease in IOP (2.4 mmHg). We found that Provider 1 used significantly higher mean TE than Provider 2 (142.4 vs 80.75 mJ / session). However, there was no significant difference in the degree of IOP change as a function of TE. There was a trend for higher TE in eyes with less trabecular meshwork pigment. Post-op complications included 5 patients (11.63%) who experienced an IOP spike greater than 15% and this group received an average TE of 183.72 mJ. All complications were self limited and none required incisional surgical intervention to achieve target IOP during the study period.
Conclusions: :
The IOP lowering effect of SLT is independent across the range of TE measured in this study. There is a tendency for IOP spikes to occur when using TE higher than 180 mJ per session. SLT across the range of TE used in this study is a useful adjunctive therapy in patients with OAG who are not achieving target IOP with ocular drug therapy.
Keywords: laser • intraocular pressure