Abstract
Purpose: :
To elucidate potential of three-dimensional optical coherence tomography (3D AS-OCT) for pinpoint identification of filtration openings from the scleral flap margins into the subcojunctival space.
Methods: :
The included were 151 glaucomatous eyes that underwent trabeculectomy. With the use of 3D AS-OCT and newly developed software for rotation and tilting the obtained OCT images, filtration opening was identified based upon our criteria; simultaneously identified pit signs in the fluid-filled cavity in both horizontal and vertical scans, corresponding to scleral flap margin in C-scan image. Also, by using newly developed software, we analyzed total 3D images of the bleb based upon reflectivity for classifying internal structures into 4 parts, fluid-filled (blank) cavity and spaces with low, middle and high reflectivity.
Results: :
In 17 (11%) of 151 eyes after trabeculectomy, neither fluid-filled cavity nor bleb wall with low reflectivity was found in entire operation fields (designated as type N, no functional bleb). In 126 (93%) of the remaining 134 eyes with potential functional blebs, pinpoint identification of filtration openings was enabled (type F, bleb with "filtration" opening) with the use of 3D AS-OCT and our newly developed software. The reasons for non-detectable filtration opening in the 8 eyes were too elevated bleb with high reflectivity causing shadow effects and resultant obscured (or no) scleral images (type H, "high" bleb) in 3 eyes, and sponge-like loose connective tissues embedded in the whole internal bleb space (type S, "sponge-like" bleb) in 5 eyes. In 97 (77%) of the 126 eyes with detectable filtration openings, only one filtration opening was noted (type F1). In the remaining 29 eyes (23%), two or more filtration openings were found (type F2). The mean intraocular pressures (IOPs) (± standard deviation) were 13.4 ± 6.5 mmHg, 15.0 ± 4.9 mmHg, 11.4 ± 3.5 mmHg, 16.2 ± 5.1 mmHg and 18.3 ± 3.8 mmHg, respectively, in types F1, F2, S, N, H. Also, bleb walls in eyes with types N and H showed higher reflectivity than other types.
Conclusions: :
Three-dimensional AS-OCT with our newly developed software enables us to exactly identify filtration opening from the scleral flap margin in most cases after trabeculectomy, suggesting a potential role for the determination of therapeutic plan for the management of glaucoma after trabeculectomy.
Keywords: imaging/image analysis: clinical • wound healing