Selective laser trabeculoplasty in primary angle-closure glaucoma after laser peripheral iridotomy: A case-control study

Purpose: To evaluate the outcomes of selective laser trabeculoplasty (SLT) in patients with primary angle closure (PAC/PACG) following a YAG peripheral laser iridotomy (PI) compared with primary open-angle glaucoma (POAG). Methods: A case-control study compared the effectiveness of SLT in PAC/PACG to POAG. Data from patients who underwent SLT after a successful PI for PAC/PACG (PAC/PACG group) with an opening of the angle for at least 180 degrees were compared with a POAG group that was randomly matched to the PAC/PACG group for age, baseline intraocular pressure (IOP), and severity of glaucoma. Data were collected on the change in IOP from baseline and reduction in number of medications following SLT in both groups. SLT was considered successful when IOP decreased by Z20% of the baseline IOP without further medical or surgical intervention or a reduction in glaucoma medications by Z1 from the baseline number while maintaining the target IOP. Results: In the PAC/PACG group, 59 eyes with persistent IOP elevation after successful PI underwent SLT in areas where the angle was open for at least 180 degrees; 41% (n=24) of PAC/ PACG had scattered peripheral anterior synechiae (PAS) of r180 degrees. In the POAG group, 59 eyes underwent SLT. Fifty-nine percent in the PAC/PACG group and 85% in POAG group had 360-degree treatment, with 74 and 78 shots at 0.53 and 0.62 mJ per laser application, respectively. In the PAC/PACG group, IOP was 19.3±6.5mm Hg at baseline and 15±3.5mm Hg10 months after SLT, and the number of medications decreased from 2.3 at baseline to 1.4 at 10 months postoperatively. In the POAG group, IOP was 19.6±5.6mm Hg at baseline, and 16.1±3.7mm Hg 11 months after SLT and the glaucoma medications decreased from 2.3 to 1.1. The postoperative IOP reduction in the PAC/PACG and POAG was not significantly different (P=0.66). The success rate of achieving clinically significant IOP reduction of 20% or more from baseline, or discontinuation of one or more of glaucoma medications was 84.7% in the PAC/PACG group and 79.6% in the POAG group (P=0.47). An IOP spike occurred in 10% (n=6) in PACG/PAC and 5% (n=3) in POAG and was controlled with topical medications (P=0.49). Conclusion: The safety and efficacy of SLT was equivalent in PAC/ PACG and POAG.