Efficacy of selective laser trabeculoplasty following incisional glaucoma surgery

Aim: To evaluate the efficacy of selective laser trabeculoplasty (SLT) in glaucomatous eyes with previous incisional glaucoma surgery.

Methods: A retrospective cohort of eyes that underwent SLT at a single institution from 2013-2015 were followed for 1y. Reduction in intraocular pressure (IOP) following SLT was evaluated in eyes with prior trabeculectomy with ExPress mini shunt (Alcon, Ft Worth, TX, USA), Ahmed valve (New World Medical, Cucamonga, CA, USA), or combined phacoemulsification-trabeculectomy. A control group was included with eyes without prior surgery that underwent SLT. Success was defined as >20% drop in IOP from pre-SLT baseline.

Results: One-hundred and six eyes were included with 53 in both the prior glaucoma surgery (PGS) and no prior glaucoma surgery (NPGS) groups. Mean pre-SLT IOP was 19.2±4.3 and 20.6±6.0 mm Hg for PGS and NPGS groups, respectively (P=0.17). Both groups produced statistically significant IOP reductions at 1 and 6mo (P<0.04). At 6mo, mean IOP reduction reached 7.3% and 10.8% for the PGS and NPGS groups, respectively (P=0.42). Overall, 27.9% and 31.7% of eyes in PGS and NPGS groups met success criteria at 1y (P=0.70). In the PGS group, eyes with baseline IOP ≥21 mm Hg had IOP reductions of 18.1% (P<0.001), 16.7% (P<0.01), and 8.4% (P=0.31) compared to eyes with baseline IOP <21 mm Hg who had IOP reductions of 2.3% (P=0.39), 3.4% (P=0.19), and 1.1% (P=0.72) at 1, 6mo, and 1y, respectively.

Conclusion: SLT is efficacious in eyes with prior incisional glaucoma surgery and results in similar IOP reductions compared to eyes without PGS. A larger IOP reduction is observed following SLT in eyes with higher pre-SLT IOP.