title: Precise identification of filtration openings on the scleral flap by three-dimensional anterior segment optical coherence tomography.
abstract: OBJECTIVE
  To elucidate the potential of three-dimensional anterior segment optical coherence tomography (3D AS-OCT) for identifying filtration openings where aqueous humor flows from the sclera into the subconjunctival space.
  
  
  METHODS
  We used 3D AS-OCT and custom software to identify filtration openings, which 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. We measured bleb parameters, and at least three different reviewers surveyed the complete 3D images of the internal structure of the filtration blebs and associated findings.
  
  
  RESULTS
  We identified filtration openings in 118 (95%) of 124 eyes. Among these 118 eyes, we found only a single filtration opening in 90 eyes (76%) and two or more filtration openings in the remaining 28 eyes (24%). Filtration openings were located in the middle third of the scleral flap margins in 57 eyes (63%) of the 90 eyes. The pattern of incision and sutures used for closure of the conjunctival flap affected the location of the openings, but additional laser suture lysis did not. In 6 (5%) of the 124 eyes, filtration openings could not be identified because of high reflectivity and/or elevated bleb wall (2 eyes), and no fluid-filled cavities because a sponge-like structure masked the filtration openings just above the scleral flap (4 eyes).
  
  
  CONCLUSIONS
  3D AS-OCT allows, in most cases, detailed evaluation of internal morphology of filtration blebs and precise identification of filtration openings on the scleral flap margins after trabeculectomy.
authors.affiliation: Department of Ophthalmology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Inoue
authors.forename: Riyo
authors.initials: R
authors.lastname: Matsumura
authors.forename: Utako
authors.initials: U
authors.lastname: Kuroda
authors.forename: Kei-Ichi
authors.initials: K
authors.lastname: Nakashima
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kawaji
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Tanihara
mesh_terms: D000368:Aged; D000869:Anterior Eye Segment / Q000473:pathology; D001082:Aqueous Humor / Q000378:metabolism*; D003228:Conjunctiva / Q000378:metabolism / Q000601:surgery; D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000378:metabolism / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007429:Intraocular Pressure; D008297:Male; D010030:Ostomy; D012590:Sclera / Q000378:metabolism / Q000601:surgery*; D013524:Surgical Flaps / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014130:Trabeculectomy