Ab-Externo Approach Achieves Higher Success Rates for Gelatin Stent Bleb

Operation of eye
Surgeon and his assistant performing operation on eye
The approach was more successful in reducing intraocular pressure by at least 20% while maintaining or decreasing glaucoma medications.

This article is part of Ophthalmology Advisor’s conference coverage from the 2021 meeting of the American Academy of Ophthalmology, held in New Orleans from November 12 to 15, 2021. The team at Ophthalmology Advisor will be reporting on a variety of the research presented by the ophthalmology experts at the AAO. Check back for more from the AAO 2021 Meeting.


Ab externo with open conjunctiva (AEO) placement is associated with higher rates of success in the placement of a gelatin stent for intraocular pressure (IOP) reduction, according to research results presented at the American Academy of Ophthalmology 2021 annual meeting held November 12-15 in New Orleans.

To determine how ab interno with closed conjunctiva (AIC) and ab externo with open conjunctiva (AEO) compared in providing success with the stents, the researchers retrospectively reviewed 65 patients who underwent placement of either approach between July 2018 and March 2021.

The 2 groups of patients possessed similar baseline demographics, medication burden, and, at most time points, IOP reduction. The exceptions for IOP reduction were at 6 months and at 1 year postoperative.

At those 2 time points, the researchers found that AEO had performed better (P =.05, P =.01, respectively).

AEO was more successful in reducing IOP at least 20%, the study shows with IOPof 18 mm Hg or less for 2 consecutive visits. 

AEO was also more successful in qualified success, which included patients who did not have to increase the number of medications following the surgery than they had utilized preoperatively (P =.01).

Complete success occurred in 37% of cases of AEO placement while 31% of AIC cases achieved that result. Seventy percent of patients who received AEO placement compared with 49% of patients who received AIC placement experienced qualified success.

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Neeson CE, Odishelidze N, Hall NE, et al. Comparing outcomes of gelatin stent placed ab interno with closed conjunctiva to ab externo with open conjunctiva. Presented at: The American Academy of Ophthalmology 2021 Annual Meeting; November 12-15; New Orleans. Abstract PO008.