Changes in choroidal area following trabeculectomy: Long-term effect of intraocular pressure reduction

Purpose To evaluate changes in the macula and peripapillary choroidal area at one year after trabeculectomy in order to determine the effect of intraocular pressure (IOP) changes. Methods This prospective longitudinal study examined 30 eyes of 30 patients with glaucoma that was uncontrolled by medical therapy. At 1 day before and at 1 year after the trabeculectomy surgery, macular and peripapillary choroidal images were recorded by enhanced depth imaging optical coherence tomography (EDI-OCT). Luminal and interstitial areas were converted to binary images using the Niblack method. Factors influencing the macular choroidal and peripapillary area were examined by multivariate analysis. Results After trabeculectomy, the mean IOP was 10.8 +/- 3.2 mmHg compared to 17.8 +/- 7.2 mmHg at baseline (P < 0.001). The total macular choroidal area after the surgery increased from 317,735 +/- 77,380 to 338,120 +/- 90,700 mu m(2), while the interstitial area increased from 108,598 +/- 24,502 to 119,172 +/- 31,495 mu m(2) (all P < 0.05). The total peripapillary choroidal area after the surgery also increased from 1,557,487 +/- 431,798 to 1,650,253 +/- 466,672 mu m(2), while the interstitial area increased from 689,891 +/- 149,476 to 751,816 +/- 162,457 mu m(2) (all P < 0.05). However, there were no significant differences observed in the luminal area before and after the surgery. A decrease in the IOP was among the factors associated with the changes in the peripapillary choroidal area. Conclusions IOP reductions after trabeculectomy led to increases in the macular and peripapillary choroidal areas for at least 1 year postoperative. Increases in the interstitial areas were the primary reason for observed changes in the choroidal area after trabeculectomy.