Anterior Segment Optical Coherence Tomography Imaging of Trabeculectomy Blebs Before and After Laser Suture Lysis

Abstract

 

Purpose:

 

To image trabeculectomy blebs before and after laser suture lysis (LSL) using anterior segment optical coherence tomography (AS-OCT).

 

Methods:

 

This was a prospective observational study of 7 patients who underwent LSL. All blebs were imaged with a prototype of the AS-OCT (Carl Zeiss Meditec Inc, Dublin, CA, USA) before and after LSL. Standardized color mono-photographs of blebs were also obtained at each visit. Blebs were assessed for the following qualitative features: bleb height, thickness of the conjunctiva in the bleb wall, apposition of the scleral flap to underlying sclera and patency of the internal ostium. High blebs were defined as total bleb height (TH) exceeding twice scleral thickness S (i.e. TH>2S), moderate height blebs as S<TH<2S and low blebs as TH<S.

 

Results:

 

7 blebs in eyes of 7 patients were imaged. There were 4 men (57.1%) and the mean age of patients was 66.0 ± 12.0 years. Pre LSL, 5 blebs were low and 2 were of moderate height. After LSL, 6 out of 7 eyes (85.7%) showed an increase in total bleb height. In these 6 eyes, the bleb wall thickness increased and the scleral flap was found to have separated from sclera with the formation of a hyporeflective area between scleral flap and sclera, suggestive of an aqueous filled space. In one eye, there was no discernable change in bleb height, cavity height or wall thickness.

 

Conclusions:

 

AS-OCT was able to demonstrate features of bleb morphology that changed after LSL. The results of this study support the potential use of AS-OCT in imaging blebs after trabeculectomy.  

 

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • wound healing