title: Noninvasive evaluation of phase retardation in blebs after glaucoma surgery using anterior segment polarization-sensitive optical coherence tomography.
abstract: OBJECTIVE
  Evaluation of bleb morphology using anterior segment optical coherence tomography (OCT) can offer important information regarding bleb function after glaucoma surgery. However, analysis of tissue properties, such as scar fibrosis of blebs, is difficult with conventional OCT. The birefringence of the blebs as susceptible measure of fibrosis scar was evaluated using polarization-sensitive OCT (PS-OCT) and its relation with bleb function was assessed.
  
  
  METHODS
  One hundred and fifty-three blebs of 122 patients that had undergone trabeculectomy or an Ex-Press tube shunt were examined. Also, in 14 blebs of 12 patients, consecutive measurements were performed for 2 months after surgery. The birefringence of blebs was evaluated by measuring alteration of phase retardation using PS-OCT. Functionality of the bleb was classified according to IOP and medication. The bleb morphology in terms of size and characteristics was evaluated using three-dimensional (3D) cornea and anterior segment OCT.
  
  
  RESULTS
  The alteration of phase retardation of blebs had the largest impact on bleb functionality than bleb morphology as shown by multiple regression analysis. In consecutive measurements, no blebs showed abnormal phase retardation until 1 week after surgery. Some blebs showed partial increase of phase retardation at 1 month after surgery.
  
  
  CONCLUSIONS
  Intrableb fibrosis can be noninvasively evaluated with PS-OCT. Evaluation of birefringence by measuring phase retardation alterations using PS-OCT suggests new approaches for the postoperative management of glaucoma blebs regarding antifibrotic treatment for preventing IOP increases.
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan Computational Optics and Ophthalmology Group, Ibaraki, Japan.
authors: Shinichi
authors: S
authors: Fukuda
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Simone
authors: S
authors: Beheregaray
authors: Computational Optics and Ophthalmology Group, Ibaraki, Japan Computational Optics Group, University of Tsukuba, Ibaraki, Japan.
authors: Deepa
authors: D
authors: Kasaragod
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Sujin
authors: S
authors: Hoshi
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Genichiro
authors: G
authors: Kishino
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Kotaro
authors: K
authors: Ishii
authors: Computational Optics and Ophthalmology Group, Ibaraki, Japan Computational Optics Group, University of Tsukuba, Ibaraki, Japan.
authors: Yoshiaki
authors: Y
authors: Yasuno
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan Computational Optics and Ophthalmology Group, Ibaraki, Japan.
authors: Tetsuro
authors: T
authors: Oshika
mesh_terms: D000368:Aged; D000869:Anterior Eye Segment / Q000473:pathology*; D001768:Blister; D016022:Case-Control Studies; D005260:Female; D005355:Fibrosis / Q000473:pathology; D018463:Filtering Surgery / Q000379:methods; D005901:Glaucoma / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D041623:Tomography, Optical Coherence; D014130:Trabeculectomy / Q000379:methods*
keywords: birefringence; fibrosis scar of blebs; polarization-sensitive optical coherence tomography