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Shin, Kang, Kim, Hong, Seong, and Kim: The Morphometric Analysis of Filtering Bleb Using Anterior Segment Optical Coherence Tomography: Pilot Study
Original Article

J Korean Ophthalmol Soc 2010;51(2):234-240.

Published online: 7 September 2010

DOI: https://doi.org/10.3341/jkos.2010.51.2.234

The Morphometric Analysis of Filtering Bleb Using Anterior Segment Optical Coherence Tomography: Pilot Study

Joo Youn Shin1, Sung Yong Kang2, Na Rae Kim1, Samin Hong1, Gong Je Seong1, Chan Yun Kim1,

1The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea

2Department 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

Received 22 May 2009       Accepted 12 October 2009

Copyright © 2010 Korean Ophthalmological Society

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.

Keywords: Anterior segment OCT, Bleb function, Intrableb morphology

References

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Figure 1.
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.
jkos-51-234f1.tif
Figure 2.
AS-OCT image and corresponding slit-lamp appearance. (A) Diffuse functioning bleb. (B) Cystic bleb. (C) Encapsulated bleb. (D) Flattened bleb
jkos-51-234f2.tif
Table 1.
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.

Table 2.
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.

Table 3.
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.

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