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Vienna 2018 Delegate Registration Programme Exhibition Virtual Exhibition Satellites 2018 Survey


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Retrospective comparison of surgical outcomes between gonioscopy-assisted transluminal trabeculotomy (GATT) and iStent

Poster Details

First Author: A.Arora CANADA

Co Author(s):    D. Wang   S. Nazarali   L. Sawatzky   M. Schlenker   I. Ahmed   P. Gooi     

Abstract Details


Purpose – Comparing the surgical outcomes including safety and efficacy between gonioscopy assisted transluminal trabeculotomy (GATT) and iStent.


Cloudbreak Eye Care (5340 1 St SW #315, T2H 0C8), Calgary, AB, Canada


The study adhered to the Declaration of Helsinki and Health Research Ethics Board was processed. 146 patients with open-angle and closed-angle glaucoma underwent either GATT or iStent procedures with the intention to treat. A retrospective chart review was conducted subsequently identifying surgical outcomes at various time points including pre-operative, 1-day, 1-week, 1-month, 3-months, and 6-months. The primary outcome assessed was the percentage of patients achieving surgical success defined as intraocular pressure (IOP) ≤ 21mmHg at 6 months on no medications or an IOP reduction of ≥20% with no medications at 6 months. Secondary outcomes included IOP and number of medications.


146 patients (74 male/72 female) were treated for glaucoma with one group receiving GATT (N=57) and the other group receiving iStent (N=89). Mean age for iStent patients was 71y (46-85) and mean age for GATT patients was 57y (15-85). Mean IOP in iStent patients decreased from 19.3±5.5mmHg to 13.2±0.9mmHg (p<0.001) and medications decreased from 1.1±1.2 to 0.9±1.1 (p=0.134) by 6-months post-operative. Mean IOP in GATT patients decreased from 22.8±9.3mmHg to 13.2±4.9mmHg (p<0.001) and medications decreased from 2.1±1.5 to 1.4±1.2 (p<0.001) by 6-months post-operative. No significant differences in IOP changes.


There was a significant decrease in mean IOP and mean number of glaucoma from baseline to 6-months post-operative for both iStent and GATT patients undergoing glaucoma treatment. Utilization of GATT with a suture (~$100 CAD) may incur an economical advantage compared to using iStent and related MIGS devices (~1000-1500 CAD) per case. The limitations of the study include a small sample size, reduced longevity in comparison time points and baseline differences between GATT and iStent populations. These limitations will be minimalized in further investigations with longer follow-up using a prospective design.

Financial Disclosure:

receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented

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