JKOS Journal of the Korean Ophthalmological Society J Korean Ophthalmol Soc 0378-6471 2092-9374 Korean Ophthalmological Society 10.3341/jkos.2010.51.2.234 jkos-51-234 Original Article The Morphometric Analysis of Filtering Bleb Using Anterior Segment Optical Coherence Tomography: Pilot Study ShinJoo Youn 1 KangSung Yong 2 KimNa Rae 1 HongSamin 1 SeongGong Je 1 KimChan Yun 1 The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea Department of Ophthalmology, University of Ulsan College of Medicine, Seoul, Korea Address reprint requests to Chan Yun Kim, MD, PhD The Institute of Vision Research, Department of Ophthalmology, EYE & ENT hospital, Yonsei University Health system (Severance hospital) #134 Shinchon-Dong, Seodaemun-Gu, Seoul 120-752, Korea Tel: 82-2-2228-3580, Fax: 82-2-312-0541, E-mail: kcyeye@yuhs.ac 09 2010 07 09 2010 51 2 234 240 22052009 12102009 Copyright © 2010 Korean Ophthalmological Society 2010 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Purpose

To evaluate intrableb morphology and function after trabeculectomy using anterior segment optical coherence tomography (AS-OCT)

 Methods

Twenty-eight post-trabeculectomy eyes from patients with primary open-angle glaucoma were examined using AS-OCT. Intrableb structures, including bleb wall thickness, subconjunctival fluid, suprascleral fluid and the route under the scleral flap, were measured at the center of the bleb using AS-OCT and were classified according to their slit-lamp appearance. Blebs were classified as successful (IOP≤18 mmHg without ocular hypotensive medication) and failed (IOP>18 mmHg or use of ocular hypertensive medication.) in order to compare parameters between the two groups.

 Results

The blebs were classified as either diffuse filtering (n=17), cystic (n=5), encapsulated (n=3) or flattened (n=3) according to slit lamp appearance and were correlated with AS-OCT images. Blebs were classified as successful and failed in order to compare parameters between the two groups. Significant differences were observed between the two groups in regard to sub-conjunctival fluid space (p=0.0004). No significant differences were observed in bleb wall thickness (p=0.098), suprascleral fluid space (p=0.87) or the route under the scleral flap (p=0.196).

 Conclusions

AS-OCT images of the intrableb structures were correlated with the appearance of the slit lamp, and a large sub-conjunctival space was associated with good bleb function. AS-OCT is useful for evaluating blebs; further studies should be performed to verify these findings.

 Anterior segment OCT Bleb function Intrableb morphology References Cairns JE Trabeculectomy. Preliminary report of a new method Am J Ophthalmol 1968666739 Picht G Grehn F Classification of filtering blebs in aberrations: biomicroscopy and functionality Curr Opin Ophthalmol 1998928 Hu CY Matsuo H Tomita G Clinical characteristics and leakage of functioning blebs after trabeculectomy with mitomycin-C in primary glaucoma patients Ophthalmology 2003110 34552 DeBry PW Perkins TW Heatly G Incidence of lateonset bleb-related complications following trabeculectomy with aberrations Arch Ophthalmol 2002120297300 Soltau JB Rothman RF Budenz DL Risk factors for aberrations filtering bleb infections Arch Ophthalmol 200011833842 Kronfeld FC The chemical demonstration of transconjunctival passage of aqueous after antiglaucomatous operations Am J aberrations 1952353845 Cantor LB Mantravadi A WuDunn D Morphologic aberrations of filtering blebs after glaucoma filtration surgery: the Indiana Bleb Appearance Grading Scale J Glaucoma 20031226671 Wells AP Crowston JG Marks J A pilot study of system for grading of drainage blebs after glaucoma surgery J Glaucoma 20041345460 Yamamoto T Sakuma T Kitazawa Y An ultrasound aberrations study of filtering blebs after mitomycin C trabeculectomy Ophthalmology 199510217706 Pavlin CJ Harasiewicz K Foster FS Ultrasound biomicroscopy of anterior segment structures in normal and glaucomatous eyes Am J Ophthalmol 19921133819 Singh M Chew PT Friedman DS Imaging of aberrations blebs using anterior segment optical coherence tomography Ophthalmology 20071144753 Leung CK Yick DW Kwong YY Analysis of bleb aberrations after trabeculectomy with Visante anterior segment optical coherence Br J Ophthalmol 2007913404 Kronfeld PC The mechanism of filtering operations Trans Pac Coast Oto Ophthalmol Soc Annu Meet 1949332340 Savini G Zanini M Barboni P Filtering blebs imaging by optical coherence tomography Clin Exp Ophthalmol 2005334839 Zhang Y Wu Q Zhang M Evaluating subconjunctival bleb function after trabeculectomy using slit-lamp optical coherence tomography and ultrasound biomicroscopy Chin Med J 2008 12112749 Theelen T Wesseling P Keunen JE Klevering BJ A plot study on slit lamp-adapted optical coherence tomography imaging of aberrations filtering blebs Graefes Arch Clin Exp Ophthalmol 200724587782 Kawana K Kiuchi T Yasuno Y Oshika T Evaluation of aberrations blebs using 3-dimensional cornea and anterior segment optical coherence tomography Ophthalmology 200911684855 Figures and Tables

Morphology of bleb using Visante TM OCT. BW=bleb wall thickness; SF=subconjunctival fluid; SS=scle-rotomy site; SF=scleral flap; R=route under scleral flap; SSF=suprascleral fluid.

AS-OCT image and corresponding slit-lamp appearance. (A) Diffuse functioning bleb. (B) Cystic bleb. (C) Encapsulated bleb. (D) Flattened bleb

Comparison of clinical characteristics and intrableb parameters between 4 different bleb type

Diffuse functioning bleb (n=17) Cystic bleb (n=5) Encapsulated bleb (n=3) Flattened bleb (n=3)
Age (y) 50.76±13.04 59.00±16.29 52.33±14.15 65.00±19.97
Sex (M/F) 14/3 2/3 3/0 2/1
Postop (months) 44.82±34.17 8.4±2.70 35±42.79 103±63.24
IOP (mmHg) 11.29±4.62 11.60±2.70 22.00±7.00 25.00±7.00
Successful/Failed* (n) 8/9 3/2 0/3 0/3
Bleb wall thickness(mm) 0.14±0.04 0.11±0.05 0.43±0.06 0.25±0.09
Subconjunctival fluid (mm) 0.48±0.34 0.73±0.39 0 0.02±0.02
Suprascleral space (mm) 0.21±0.13 0.14±0.05 2.20±0.36 0.08±0.02
Route under scleral flap (+/-) 17/0 3/2 2/1 0/3

Successful: IOP≤18 mm Hg without ocular hypotensive medication; Failed: IOP>18 mmHg or use of ocular hypotensive medication.

Comparison of clinical characteristics and intrableb parameters between successful and failed bleb groups

Successful (n=12) Failed (n=16) p-value
Age (y) 51.75±17.04 55.50±12.57 0.51
Sex (M/F) 7/5 14/2 0.1
Postop (months) 23.41±23.94 58.56±46.64 0.115
IOP (mmHg) 9.42±3.73 17.37±6.77 0.001*
Bleb wall thickness (mm) 0.13±0.05 0.22±0.13 0.09
Subconjunctival fluid (mm) 0.70±0.37 0.21±0.24 0.004*
Suprascleral space (mm) 0.24±0.16 0.53±0.84 0.87
Route under scleral flap (+/-) 11/1 11/5 0.2

Successful: IOP≤18 mmHg without ocular hypotensive medication; Failed: IOP>18 mmHg or use of ocular hypotensive medication.

p<0.05.

Comparison of characteristics and intrableb parameters between successful and failed bleb groups in diffuse functioning bleb and cystic bleb

Successful (n=12) Failed (n=10) p-value
Bleb type (n)
 Diffuse functioning bleb 8 9
 Cystic bleb 4 1
Age (y) 51.75±17.05 53.60±9.63 0.76
Sex (M/F) 7/5 9/1 0.09
Postop (months) 23.42±23.94 52.30±37.98 0.06
IOP (mmHg) 9.42±3.73 13.70±3.62 0.01*
Bleb wall thickness (mm) 0.13±0.05 0.14±0.04 0.73
Subconjunctival fluid (mm) 0.70±0.37 0.33±0.22 0.01*
Suprascleral space (mm) 0.24±0.16 0.16±0.04 0.12
Route under scleral flap (+/-) 11/1 9/1 0.89

Successful: IOP≤18 mmHg without ocular hypotensive medication; Failed: IOP>18 mmHg or use of ocular hypotensive medication.

p<0.05.