The Effect of Trabeculectomy on Disc Tissue Blood Flow Across Quadrants in Open-Angle Glaucoma.

Abstract

Prcis: Trabeculectomy increases tissue blood flow superior and temporal in the optic nerve head. Improvement of tissue blood flow superior and temporal in the optic nerve could be an indicator of the effectiveness of glaucoma treatment.

Purpose: To investigate changes in tissue blood flow at the optic nerve head before and after trabeculectomy.

Methods: This prospective study included 53 eyes who underwent trabeculectomy. The mean blur rate of the tissue area (MT) was determined using laser speckle flowgraphy (LSFG) preoperatively and 1 and 3 months postoperatively. MT, LSFG waveform parameters (blowout score [BOS] and resistivity index [RI]), intraocular pressure (IOP), and ocular perfusion pressure (OPP) were analyzed preoperatively and at 3 months postoperatively.

Results: Postoperatively, IOP decreased (17.9±6.0 to 9.2±3.4 mmHg) and OPP increased (43.3±9.2 to 52.1±6.4 mmHg). As previously described, BOS increased (73.5±8.3 to 76.7±6.5; P<0.001) with an inverse correlation to IOP and in proportion with OPP; RI decreased (0.40±0.1 to 0.35±0.08; P<0.001) with an inverse correlation to OPP and in proportion to IOP. However, we found that MT increased significantly after surgery (7.9±2.2 to 8.8±2.2 AU; P=0.002) without significant association between MT and IOP or OPP. In the four quadrants of the optic nerve head (ONH), BOS significantly increased, while RI significantly decreased after surgery in all quadrants. On the other hand, MT significantly increased in the superior and temporal quadrants only.

Conclusions: Blood flow increases in the superior and temporal of optic nerve head.