Abstract
Purpose :
IOP lowering effect of glaucoma drainage implant (GDI) surgery is believed to be dependent on the permeability of aqueous humor through encapsulated tissue around the plate. However, the abnormalities of the trabecular meshwork (TM) and Schlemm’s canal (SC) may also affect the outcome of this surgery.
We have investigated the risk factors for the failure of (GDI) surgery by dividing group I (required two DGIs) and II (required single DGI).
Methods :
Thirty eight eyes of 33 cases (group I) and 269 eyes of 250 cases (group II) were clinically investigated as for age, sex, pre-op IOP, type of glaucoma, the number of previous glaucoma surgery, combination of trabeculectomy (TLE), type of GDI, final IOP and success rate (IOP<21 and IOP reduction>20%). TLE samples which were obtained before the first or second GDI surgeries were also histologically investigated by dividing group I (22 eyes) and II (26 eyes, failed and TLE combined eyes were excluded). The refractory nature of glaucoma was accessed by the following histological parameters; the length of SC stained by thrombomodulin, percentage of thrombomodulin-negative area (PTNA), intensity of D240 (podoplanin) staining (grading score: 0-III) in juxtacanalicular meshwork (D240-JCT), corneoscleral meshwork (D240-CSM) and uveal meshwork (D240-UM).
Results :
Three years success rates were 69.4% and 80.0% in group I and II respectively. Pre-op IOPs (P<0.001) and IOP reduction (P<0.001) in group II were significantly higher in the eyes of TLE combined GDI. Male (P=0.006) and younger patients (P=0.006) in group I were significantly dominant when compared to group II. SC length (P=0.0092), and intensity grading score of D240-JCT (0.0140) in group I were significantly smaller than those in group II.
Conclusions :
The failure of GDI surgery may be significantly dependent on severity of impaired outflow routes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.