Abstract
Purpose :
The development of various types of minimally invasive glaucoma surgery (MIGS) has revolutionized glaucoma management. Ab Interno Canaloplasty (ABiC) and Gonioscopy Assisted Transluminal Trabeculotomy (GATT) are both gonio-based MIGS procedures. While both ABiC and GATT may use the same type of illuminated microcatheter to transverse the Schlemm’s canal 360 degrees, ABiC uses ocular viscoelastic device to expand the aqueous drainage system preserving the trabecular meshwork (TM) while GATT cleaves the entire TM exposing the Schlemm’s canal directly to the anterior chamber. Although both ABiC and GATT have been reported to effectively lower the intraocular pressure (IOP), there has been no study comparing the surgical outcomes between these two approaches. This study aims to compare the effectiveness of IOP reduction between ABiC and GATT in eyes with primary open angle glaucoma (POAG).
Methods :
A retrospective chart review of patients with POAG who underwent ABiC or GATT at Yale Eye Center/Yale New Haven Hospital between 1/1/2021 and 06/30/2022 was performed. Inclusion criteria were no prior surgical intervention for POAG and at least 6 months post-op follow-up. Statistical analysis comparing percent change in post-op IOPs was performed using the Mann Whitney U test. Adverse events of both procedures were also analyzed.
Results :
12 patients (17 eyes) who underwent ABiC and 18 patients (19 eyes) who underwent GATT were identified. Patients who have secondary glaucoma other than POAG, patients who have undergone prior glaucoma surgeries or patients who did not complete at least 6 months of follow up after the surgeries were excluded. 5 patients (6 eyes) who underwent ABiC and 6 patients (6 eyes) who underwent GATT were included in the study. The percent changes in IOP before and after the surgeries were calculated. The median percent change in IOP was noted to be -36.5% for ABiC group and -42.5% for GATT group. Wilcoxon rank sum test was performed, and the P-value was noted to be 0.38. No major complications have been observed.
Conclusions :
Both ABiC and GATT effectively reduce the IOP in POAG with similar safety profile. The median percent decrease in IOP is higher in GATT group than ABiC group but the difference is not statistically significant. Further studies with larger sample size may be needed.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.