In a 74-eye study led by Swiss researcher Kevin Gillmann, MD, MBBS, FEBOphth, MArch, and reported in the Journal of Glaucoma, it was found that success with the Xen gel stent (Allergan) in the initial eye was a strong predictor of success in the fellow eye, with a ratio of 16:1 in favor of success. If the Xen stent failed in the initial eye, failure in the fellow eye at 2 years was 92%.

"This study highlights, for the first time, the dramatic extent to which the outcomes of XEN implantations in both eyes are interconnected,” Dr. Gillmann told Glaucoma Physician. “It also suggests that, contrary to what was previously observed in trabeculectomies, longer intervals between bilateral Xen implantations may not be detrimental to the second eye. Clinically, this means that observing the outcome of the first-operated eye to decide on the best procedure for the fellow eye may be a valid therapeutic strategy in higher-risk cases. Yet, most systemic factors affecting glaucoma progression and response to treatment still remain unclear, and may constitute key considerations in the future development of truly individualized glaucoma therapy."