Abstract
Purpose:
Trabeculectomy (TLE) is the most common surgical procedure for uncontrolled glaucoma. TLE is the most effective procedure known. Intraocular pressure (IOP) after TLE depends on the bleb’s absorption function. In this study, we quantified the bleb’s structure and analyzed its function using anterior segment-optical coherence tomography (OCT), specifically the CASIA system (SS-1000; TOMEY, Nagoya, Japan). We also examined the correlation between various parameters of the bleb’s structure and IOP after TLE.
Methods:
This study included 34 eyes of 30 patients with various types of glaucoma. All patients received TLE with 0.04% MMC from April and August 2012. ( mean 69.6±13.6 years, male/female 14/16). All subjects underwent TLE with 0.04% MMC and used three types of eye drops (0.5% Moxifloxacin, 0.1% Betamethasone sodium phosphate, 0.5% Tranilast). We scanned the bleb just on the scleral flap in 8 directions within a 16mm range, and drew the contour lines of blebs and clefts manually. The correlations between the bleb’s parameters (cleft volume, bleb volume, vertical/Horizontal brightness of cleft, and vertical/Horizontal brightness of bleb) and IOP were analyzed at 1W (1 week ), 2W (2 weeks) , 1M (1 month) , and 3M (3 months) after TLE respectively on Spearman's rank correlation coefficient. Similarly, the comparison between IOP after TLE and IOP before TLE was analyzed on the Kruskal Wallis test.
Results:
IOP at all measurement points after TLE decreased significantly compared to the IOP before TLE. The IOP at 1W showed a significant correlation with vertical brightness of bleb at 1W, horizontal brightness of bleb at 1W, and cleft volume at 1W (r=0.40; p=0.029, r=0.41; p=0.037, and r=-0.43; p=0.027, respectively). The cleft volume at 1M and 3M, and the vertical brightness of the bleb at 2W correlated with IOP at 3M (r=-0.67; p=0.005, r=-0.59; p=0.012, and r=0.59; p=0.034, respectively).
Conclusions:
Bleb’s brightness and cleft volume were associated with IOP after TLE. AS-OCT is a useful tool to evaluate the bleb’s function in the present and future.
Keywords: 421 anterior segment •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)