Abstract
Purpose:
To quantify filtering bleb parameters using three dimensional anterior-segment optical coherence tomography (3D AS-OCT).
Methods:
Prospective observational study. Patients who underwent trabeculectomy with mitomycin C were assessed 2 weeks and 3 months after trabeculectomy. At each visit, intraocular pressure (IOP) was measured and 3D AS-OCT images of the bleb were obtained. Total bleb height, fluid-filled cavity height, bleb wall thickness and bleb wall intensity were measured using custom software. Filtration openings in the 3D AS-OCT image were defined by pits and/or troughs in fluid-filled cavities in both horizontal and vertical rasters and corresponding C-scan images of scleral flap margin in the blebs, and the number and site of filtration opening were analyzed. The localizations of filtration openings were recorded as the distance between the top of the scleral flap and the filtration opening (TFD).
Results:
Forty-three eyes of 43 subjects were examined. IOP were 10.1 ± 5.0 and 15.7 ± 8.9 mm Hg, total bleb heights were 0.84 ± 0.29 and 0.89 ± 0.42 mm, fluid-filled cavity heights were 0.35 ± 0.28 and 0.36 ± 0.30 mm, bleb wall thicknesses were 0.47 ± 0.25 and 0.51 ± 0.26 mm, bleb wall intensities were 166.6 ± 33.5 and 158.4 ± 39.0 optical density, numbers of filtration openings were 1.4 ± 0.6 and 1.1 ± 0.7, and TFDs were 1.9 ± 0.6 and 1.9 ± 0.6 mm in the right side and 1.9 ± 0.6 and 1.9 ± 0.5 mm in the left side at the visits 2 week and 3 months after trabeculectomy, respectively. IOP value was significantly increased (P <0.001), and number of filtration opening was significantly reduced (P = 0.025). Every bleb parameter at 2 weeks was positively correlated with that at 3 months after trabeculectomy. TFD at 2 weeks was also positively correlated with that at 3 months in both right and left sides (P = 0.032 and 0.005, respectively). Among all measured bleb parameters at 2 weeks, only bleb wall density and number of filtration openings were correlated with IOP at 3 months after trabeculectomy (P = 0.017 and 0.042, respectively).
Conclusions:
3D AS-OCT was useful to quantify time-dependent changes in bleb morphology after trabeculectomy. Bleb wall density and number of filtration openings at 2 weeks after trabeculectomy may be a prognostic factor of IOP at 3 months.
Keywords: 550 imaging/image analysis: clinical •
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