Relationship Between Changes in the Choroidal Structure and Blood Flow of the Macula After Trabeculectomy.

Purpose: To elucidate the relationship between changes in the choroidal structure and blood flow of the macula after trabeculectomy. Methods: A prospective study of 30 eyes of 30 patients with glaucoma who underwent trabeculectomy. Enhanced depth imaging optical coherence tomography with choroidal image binarization and laser speckle flowgraphy of the macula were performed at baseline and 1, 3, and 6 months postoperatively. Mixed-effects models with adjustment for confounders were used to analyze longitudinal changes in the mean choroidal thickness (mCT), mean choroidal vascular thickness (mCVT), mean choroidal interstitial thickness (mCIT), and mean blur rate (MBR). Results: The decrease in the intraocular pressure (IOP; 45%-51%) and axial length (0.5%-0.8%) and the increase in ocular perfusion pressure (OPP; 34%-38%), mCT (16%-19%), mCVT (16%-20%), mCIT (17%-20%), and MBR (22%-25%) were significant at each postoperative time point (all P < 0.001). In the multivariate analysis, the mCVT changes were positively correlated with the OPP and MBR changes (P = 0.04 and P < 0.001, respectively), whereas the mCIT changes were negatively correlated with IOP changes (P = 0.005). The MBR changes correlated significantly with changes in mCVT but not mCIT (P < 0.001 and P = 0.39, respectively). Conclusions: Thickness changes in the intraluminal and extraluminal parts of the choroid were closely associated with changes in blood flow and IOP, respectively, although both parts thickened comparably after IOP reduction by trabeculectomy. Translational Relevance: The choroid reacts to IOP reduction differently between the intraluminal and extraluminal areas, blood flow dependence in the vascular area, and IOP dependence in the stromal area.