Gonioscopy-assisted transluminal trabeculotomy (GATT)


Ronald L. Fellman

Davinder S. Grover

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Purpose: To describe the evolution of trabeculotomy from ab externo to ab interno techniques culminating in modern-day gonioscopy-assisted transluminal trabeculotomy (GATT), including indication, technique, and outcomes.
Methods: Review the indications, techniques, and literature regarding GATT including surgical pearls from
the authors.
Results: GATT is effective in reducing intraocular pressure (IOP) in different types of glaucoma as a standalone or combination procedure and is typically reserved for mild to moderate glaucomatous disease. Patients with advanced glaucoma may require subnormal IOPs, which may be difficult to achieve with circumferential canal surgery. GATT typically lowers IOP on average to a mid-teen level, which usually corresponds to a 40% reduction in IOP along with a significant reduction in topical medications. Congenital and especially juvenile glaucoma patients respond extremely well to GATT, with a significant reduction in IOP oftentimes requiring no long-term topical postoperative medications. Surprisingly, patients post-failed conventional outflow procedures are still excellent candidates for circumferential canal-based surgery.
Conclusion: GATT is a stepping-stone in the evolutionary pathway of trabeculotomy. The role of GATT continues to be defined, especially in light of suture GATT, a much less expensive technique that has outstanding global appeal. Circumferential trabeculotomy reduces IOP by cleaving open a diseased outflow tract without bleb formation and it continues to have a valuable role in IOP reduction. The next step in the evolution of all canal-based surgeries should be in the direction of wound healing in order to maintain adequate flow through the newly created area of decreased outflow resistance.

New Concepts in Glaucoma Surgery Series: Volume 1, pp. 95-106 #7
Edited by: John R. Samples and Iqbal Ike K. Ahmed
© Kugler Publications, Amsterdam, The Netherlands

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