Imaging of Trabeculectomy Blebs with Visante Anterior Segment
Optical Coherence Tomography after Digital Ocular Compression
Department of Ophthalmology & Visual Science, College of Medicine, Catholic University of Korea, Seoul, Korea
Myung Douk Ahn, M.D., Ph.D, Hae-Young Lopilly Park, M.D.
• Response to ocular compression
Purpose
Baseline
To investigate change of intra-bleb morphology of functioning
After ocula P Valu
r massage
e
15.61±5.5
<0.001
13.88±3.36
*
7
trabeculectomy blebs with anterior segment optical coherence
Intraocular pressure, mean (mmHg)
tomography (AS-OCT) after digital ocular compression.
Horizontal length of the internal fluid-filled
<0.001
cavity,
2.28±1.78 2.41±1.96
*
mean (mm)
Vertical length of the internal fluid-filled cav
<0.001
ity,
2.19±1.77 2.32±2.10
*
mean (mm)
Methods
Primary open angle glaucoma patients who had previously undergone
trabeculectomy surgery between 2004 and 2010 were enrolled.
IOP and AS-OCT images of the bleb were taken before and after
ocular compression. AS-OCT images were taken by one examiner (HY)
with the following procedure: patients were asked to look down and
the upper lid was retracted to expose the bleb as much as possible in
the superior bulbar conjunctiva, taking care to avoid pressure on the
Height of the internal fluid-filled cavity,
mean (mm)
0.36±0.54 0.45±0.66 0.021*
Maximum bleb wall thickness, mean (mm)
0.40±0.29 0.45±0.72 0.243*
Total bleb height, mean (mm)
1.30±1.61 1.44±1.58 0.017*
Appearance of hyporeflective areas, number
<0.001
18 (26.5) 38 (55.9)
†
(%)
<0.001
Number of microcysts, mean
0.46±0.72 1.69±1.56
*
• Changes of intrableb parameters with IOP change.
globe or bleb. Initially, AS-OCT images were obtained for each bleb in
two directions: first, a radial section perpendicular to the limbus
through the site of a peripheral iridectomy and second, a section
tangential to the limbus, through the site of maximal bleb elevation.
The bleb height, wall thickness, internal cavity height, and both the
horizontal and vertical length of the internal cavity of the bleb were
measured.
A, Slit-lamp morphology of a bleb. B, Horizontal slice image of the bleb. The
horizontal length (HL) and the height (arrow) of the internal fluid-filled cavity (*)
The relationship between IOP change and intrableb parameters of AS-OCT (A-D).
are shown. C, Vertical slice image of the bleb. The vertical length (VL) of the
The horizontal length (HL) and vertical length (VL) showed the strongest
internal fluid-filled cavity (*) and the maximum bleb wall thickness (arrow) are
relationship with IOP change. It was further analyzed by time elapsed after
shown. The sclerotomy site (S) and iridectomy site (IR) are depicted. Microcyts
trabeculectomy (E-H) and significant changes happened between 6-12 months
(M) with more than 10 μm in diameter were counted in the images. D, The total
after surgery. There were only small changes in the AS-OCT parameters after
bleb height (BH) is the maximum distance between the internal surface of the
this period.
fluid-filled cavity (*) and the bleb surface. The hyporeflective area is shown
Correlation
Coefficitent
P Value
0.717
<0.0001
0.866
<0.0001
Height of the internal fluid-filled cavity
0.655
<0.0001
Total bleb height
0.464
<0.0001
Number of microcysts
0.632
<0.0001
(arrows).
Results
Horizontal length of the internal fluid-filled ca
vity
Vertical length of the internal fluid-filled cavit
y
• Baseline characteristics
Number of eyes
Gender (M/F)
Age, mean (years)
Interval between surgery and examination, mean (m
onths)
≤ 3 months
3-6 months
6-12 months
>12 months
Mean intraocular pressure (mmHg)
Mean number of eyedrops
Bleb morphology at examination, number (%)
Diffuse filtering
Cystic
68
37/31
65.32±10.25
25.44±32.40
18
17
20
13
17.82±5.34
2.1±0.7
38 (55.9)
30 (44.1)
Conclusions
Digital ocular compression may be useful in maintaining the
bleb morphology when it is used until 6 months after surgery.
And the response to ocular compression was different by bleb
morphology.