Comparison between open-angle glaucoma and angle-closure glaucoma regarding the short-term optic disc vessel density changes after trabeculectomy

To compare the microvasculature of the optic disc in open-angle glaucoma (OAG) and angle-closure glaucoma (ACG) after trabeculectomy. This study included 34 patients divided into two groups based on the angle: (1) the OAG Group, which included 24 eyes from 24 patients, and (2) the ACG Group, which included ten eyes from 10 patients. All patients were subjected to comprehensive ophthalmic examinations. It included best-corrected visual acuity (BCVA), Goldmann applanation tonometry, gonioscopy, slit-lamp biomicroscopy, dilated fundus examination, and stereoscopic examination of the optic disc. The central corneal thickness was measured using a Nidek AL scan optical biometer. The visual field was evaluated by standard automated perimetry using Humphrey Field Analyzer (24-2 Swedish interactive threshold algorithm; Carl-Zeiss Meditec, Dublin, CA). Moreover, optical coherence tomography angiography (OCT-A) was performed utilizing the RTVue XR Avanti scanner (Optovue Inc., Fremont, CA, USA) preoperatively as well as 1 month after surgery. There was a statistically significant increase in optic disc vessel density (VD) in the whole image, radial peripapillary, inferior, superior, temporal, and nasal quadrant in OAG after surgery. Regarding the change in VD after surgery in ACG patients, there was a statistically significant increase in optic disc VD in the whole image, radial peripapillary, inferior, superior, temporal, and nasal quadrant in ACG after surgery.Regarding the percentage of VD change following trabeculectomy surgery, there were highly significant differences between the two groups for the whole image, radial peripapillary, inferior quadrant, and temporal quadrant VD. Statistically significant changes were also observed in the superior and nasal quadrants of VD. However, no significant change in VD was detected within the disc. In conclusion, the optic disc VD improved after the reduction of intraocular pressure (IOP) by surgery in both OAG and ACG. However, ACG demonstrated a significant improvement than the OAG.