Early postoperative visual acuity changes after trabeculectomy and factors affecting visual acuity

Purpose To investigate the early visual acuity (VA) changes that occur after trabeculectomy and their reversal with recovery. Method Two hundred ninety-two eyes of 292 patients after initial trabeculectomy as a standalone procedure fulfilling the following conditions were included: 1) patients with a postoperative follow-up of at least 3 months; 2) patients with preoperative corrected VA less than 0.5 logMAR equivalent; 3) patients with reliable results of visual field; and 4) patients who had open angle glaucoma. VA and intraocular pressure (IOP) changes during the first 3 months after surgery and factors affecting VA postoperatively at 3 months were investigated. Results The mean IOPs (mmHg) after trabeculectomy were significantly lower than preoperatively during the entire period (P < 0.0001). The mean corrected VA for all patients was 0.06 +/- 0.17, 0.24 +/- 0.38, 0.19 +/- 0.26, and 0.14 +/- 0.27 preoperatively and at 1 week, 1 month, and 3 months postoperatively, respectively, showing a significant decrease from the preoperative period at all time points (P < 0.0001). VA loss of two or more levels was observed in 13 eyes (4.45%) at 3 months postoperatively. Foveal threshold (FT), shallow anterior chamber (SAC), and choroidal detachment (CD) affected the change in VA before and at 3 months after surgery (P < 0.0001, P = 0.0002, P = 0.0004, respectively). The factors that had significant effects on VA change were FT, SAC, and CD in POAG, FT and hypotonic maculopathy in NTG, and FT in XFG (p < 0.05). Conclusion The frequency of serious vision loss was 4.45% for two or more levels of vision loss, and early postoperative VA changes after trabeculectomy may not be reversed even 3 months later. VA loss is influenced by preoperative FT, postoperative SAC and CD, but the impact of postoperative complications vary with disease type.