The purpose of this study was to investigate morphological changes in the outflow pathway from Schlemm’s canal (SC) to the intrascleral vessels (ISVs) in POAG eyes through comparisons with age-matched, normal control eyes using light microscopy and morphometric analysis. We hypothesized that there would be a reduction in the size and number of ISVs when SC becomes narrower and collapsed in the eyes with POAG and there would be no reduction in size and number of ISVs when SC is open in eyes with POAG. 11 normal eyes from 10 donors (63-92 years old) without a history of ocular diseases and 10 POAG eyes from 6 donors (67-90 years old) with clinically confirmed diagnoses of POAG were acquired. The eyes were fixed and embedded. The sections of anterior chamber angle (2-3 μm in thickness) were cut, stained with sectioning procedures, and imaged using a light microscope. 36 images from 11 normal eyes and 40 images from 10 glaucomatous eyes were examined and analyzed in this study. Cross-sectional area (CSA), width, height of SC and percentage collapse of SC as well as the number and CSA of ISVs were measured within each quadrant of the eye. Statistical analyses were conducted using one-way ANOVA and Kruskal-Wallis test in the IBM SPSS software. A significant reduction in height, width, and CSA of SC, and a significant increase in percentage of SC collapse were found in 70% of POAG eyes, while open SC was found in 30% of POAG eyes when compared to normal eyes. Decreased sizes and number of ISVs were observed in 70% of POAG eyes with narrower and collapsed SC, but these changes did not reach statistical significance. Decreased sizes of ISVs were observed in 30% of POAG eyes with open SC, although these changes did not reach statistical significance. The results suggested that smaller and collapsed SC was found in 70% of eyes with POAG. Ultimately, the decreased size and number of ISVs found in POAG eyes may be secondary to decreased size and collapse of SC in POAG pathology.

Purpose To evaluate the effectiveness and safety of Selective Laser Trabeculoplasty (SLT) with the SLT mode of the VISULAS ® green laser in patients with primary open-angle glaucoma (POAG). Methods This prospective, interventional multicenter clinical investigation included patients with POAG who either needed a treatment escalation because the individual intraocular pressure (IOP) target was not met or treatment initiation and had an IOP ≥ 17 mmHg at baseline in the study eye. The study was conducted in five research centers across Germany. Approximately 100 laser applications were delivered to 360° of the trabecular meshwork. Glaucoma medications were not modified during the 3-month follow-up to allow evaluation of the sole effect of VISULAS ® green with SLT. Efficacy outcomes were postoperatively absolute and relative IOP changes at 1 and 3 months. Safety outcomes analyzed the rate of intra- and postoperative adverse events. Results Thirty-four eyes of 34 POAG patients were included. The overall mean number of preoperative glaucoma medications was 2.2 ± 1.4 in 29 treated eyes, 5 eyes were treatment naïve. Mean baseline IOP (mmHg) was 21.0 ± 2.69 and was reduced by − 3.53 ± 3.34 [95% CI − 4.61; − 2.45] and − 3.59 ± 3.41 [95% CI − 4.64; − 2.53] at the 1- and 3-month follow-up, respectively (p < 0.0001), with 48.5% of cases achieving a ≥ 20% IOP reduction at 3 months [95% CI = 30.8%; 66.5%]. The mean relative IOP reduction was − 16.4% and − 16.3% at 1 and 3 months, respectively (p < 0.0001). Potentially device- or procedure-related adverse events were mild to moderate and included 3 postoperative IOP-spikes and 6 reports regarding eye pain and discomfort. All were resolved without sequelae. Conclusions SLT performed with the VISULAS ® green laser achieved clinically significant additional IOP reductions in medically treated as well as in treatment naïve eyes with POAG and there were no relevant safety issues. The results are comparable to other reported SLT studies.