Changes in choroidal area after intraocular pressure reduction following trabeculectomy

PURPOSE: To investigate changes of the macular and peripapillary choroidal areas after trabeculectomy. METHODS: This prospective and interventional study examined 74 eyes of 74 patients with glaucoma uncontrolled by medical therapy. Enhanced depth imaging optical coherence tomography (EDI-OCT) recorded macular and peripapillary choroidal images at 1 day before trabeculectomy and at 2 weeks after surgery. The Niblack method was used to covert luminal and interstitial areas to binary images. RESULTS: At baseline, the mean intraocular pressure (IOP) was 17.6±6.3 mmHg, while it was 6.5±2.9 mmHg after trabeculectomy (P < 0.001). Increases were observed for the macular choroidal area after the surgery, with the total area increasing from 317,853±95,728 μm(2) to 368,597±104,393 μm(2), while the luminal area increased from 210,355±73,650 μm(2) to 249,464±77,195 μm(2), and the interstitial area increased from 107,498±27,613 μm(2) to 119,133±31,811 μm(2) (all P < 0.001). Increases were also observed after the surgery for the peripapillary choroidal area, with the total area increasing from 1,629,440±460,429 μm(2) to 1,974,289±500,496 μm(2), while the luminal area increased from 920,141±328,690 μm(2) to 1,179,843±357,601 μm(2), and the interstitial area increased from 709,299±153,179 μm(2) to 794,446±169,029 μm(2) (all P < 0.001). There was a significant increase in the ratio of the luminal to choroidal area in the macular area (67.2%) and in the peripapillary area (59.1%). Factors associated with the changes in the peripapillary choroidal area included decreases in the diastolic blood pressure and IOP. CONCLUSIONS: A reduction in the IOP after trabeculectomy led to increases in the macular and peripapillary choroidal areas. Observed changes in the choroidal area after trabeculectomy are primarily due to increases in the luminal areas.