The hypotensive effect of selective laser trabeculoplasty depending on iridocorneal angle pigmentation in primary open angle glaucoma patients

INTRODUCTION Selective laser trabeculoplasty (SLT) is applied to reduce intraocular pressure in primary open angle glaucoma therapy. It selectively subjects trabecular pigmented cells to a pulsed, frequency-doubled Nd:YAG laser. The biostimulatory effect on trabecular macrophages was also postulated even in low-pigmented angles. The aim of the study was to assess the hypotensive effectiveness of SLT depending on the degree of iridocorneal angle pigmentation. MATERIAL AND METHODS Sixty-three eyes of 53 patients with primary open angle glaucoma (POAG) were included in this study and than divided into three subgroups, dependind of iridocorneal angle pigmentation. All subjects underwent SLT on 270 degrees of the angle. Intraocular pressure (IOP) was assesed at baseline and 6 weeks after the laser procedure. RESULTS Six weeks post-SLT mean IOP reduction was 2.63 mm Hg. The degree of IOP reduction showed a significant correlation with angle pigmentation. Intraocular pressure fell by 2.06 mm Hg, 2.46 mm Hg and 4.75 mm Hg in subgroups with low, marked and high pigmentation, respectively. CONCLUSIONS The SLT procedure most effectively reduces IOP only in the subgroup of POAG patients with marked angle pigmentation and it is equal to clinically succesfull hypontesive therapeutic effect, according to European Glaucoma Society guidelines. However, lower hypotensive effect in other study subjects may also be the valuable addition to pharmacological therapy of glaucoma.