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Results of the retrobulbar shunt in glaucoma management

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First Author: F.March De Ribot SPAIN

Co Author(s):    W. Sponsel   M. Montelongo   L. Chu   V. Saka   R. Chitedze   R. Craven     

Abstract Details


To examine the efficacy and safety of a commercial model of the retrobulbar shunt  Anterior chamber to Back of the eye (A2B) in lowering intraocular pressure (IOP) and medication requirement after the failure of all other IOP-lowering therapies (including trabeculectomy with antimetabolites and tube shunt procedures).


Ophthalmology Department, University Hospital


This is a single-site, prospective, nonrandomized study. Individuals who had failed all other IOP-lowering therapies were considered candidates for A2B shunt implantation. Shunts that were consecutively implanted from Jan. 2019-Feb 2020 were included in this analysis. Prespecified outcome measures include IOP control with and without supplemental medication, success rate, medication use, and adverse events.


26 eyes of 23 patients wereassessed (mean age 43.9 ± 5.1) received the A2B shunt, after a mean of 2.2 prior incisional glaucomasurgeries without sustained success. 92% of the eyes had previously failed tubeshunt surgeries, after the failure of other surgeries. The mean IOP (mmHg ± SEM) dropped from a baseline of 34.6 ± 2.6 to 9.5 ± 1.5(-25.1 mmHg, -72%), 16.2 ± 2.7(-18.4 mmHg, -53%), 15.5 ± 1.5 (-19.1 mmHg, -55%), 16.7 ± 1.5 (-17.9 mmHg, -51%), 18.2 ± 1.0 (-16.4 mmHg, -47%), and 16 ± 2.12 (-18.6 mmHg, -53%) at 1, 7, 30, 90, 180, and 365 days after surgery, respectively(p < 0.001). The mean number of glaucoma medications (± SEM) at 30, 90, 180, and 365 days dropped from baseline of 2.3 ± 0.3 to 0.24 ± 0.13, 0.26 ± 0.14, 0.33 ±0.18, and 0.2 ± 0.2 respectively (p<0.0001). There were no complicationsincluding leaks, infections, migrations, erosions, persistent corneal edema, orserious long-term adverse events.


Conclusions: TheA2B shunt is an effective rescue therapy in patients that have manifestly failed other IOP-lowering procedures.  Discussion: The surgery redirects aqueous humor into the retrobulbar space resulting in a highly effective method to lower IOP, with no significant fibrosis reaction, ending in less surgical failure. The operation is similar to traditional tube shunts but requires only a fraction of the time, in part because it omits the scleral fixation of a plate. The risk of aqueous leakage or tube/tutoplast exposure is limited because of the intrinsic properties of retrobulbar fat prompts it to create a one-way valve system.

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