Table 1.
Demographic Subject Data.
Fig 1.
Magnetic resonance imaging (MRI) of the orbit.
Coronal images show a Baerveldt Glaucoma Implant (BGI) in the superotemporal quadrant (A, C) and an Ahmed Glaucoma Valve (AGV) in the inferotemporal quadrant (B, D) 6 months postoperatively. With high magnification views (C, D), layers of fluid accumulation with the same intensity as intraocular fluid (arrowheads) are seen under (inner bleb) and over (outer bleb) the low-intensity area that corresponds to the endplate (arrows). With three-dimensional views of filtering blebs obtained by the volume-rendering process (E, F), the inner and outer blebs are seen clearly. In these cases, the bleb volume is calculated to be 646.0 mm3 after BGI (E) and 272.2 mm3 after AGV implantation (F).
Fig 2.
Definitions of magnetic resonance imaging-measured parameters.
(A) Line a connects both edges of the corneal limbus on the axial scan image at the level of the anterior edge of the shunt is seen most anteriorly. Line b passes the anterior edge of the endplate and is parallel to line a. Line c passes the inner surface of the central cornea and is parallel to line a. The number 1 indicates the distance between lines a and b, and 2 indicates the distance between lines b and c. (B) Line d connects both edges of the endplate on the coronal scan image at the level of the width of the endplate seen is the longest. Line e passes the center of the endplate and is parallel to line d. Line f is parallel to line d and passes the nearest point from line d to the orbital bony wall. The number 3 indicates the distance between lines e and f. (C) The bleb thickness is the sum of the inner and outer bleb heights measured at the midline of the endplate on the same image used for the distance 3 measurements.
Table 2.
MRI-Measured Parameters.
Fig 3.
The correlations between the postoperative intraocular pressure (IOP) level and bleb volume.
The oval area indicates a 95% bivariate normal ellipse.
Table 3.
Correlations between IOP Levels and MRI-Measured Parameters.
Table 4.
Comparisons between Ahmed Glaucoma Valve (AGV) and Baerveldt Glaucoma Implant (BGI) groups.