Shunts to Divert Aqueous Humor to Distant Epithelialized Cavities After Keratoprosthesis Surgery

Abstract

The shunt arrangement, which connects the anterior chamber to potentially microbe-populated cavities or to the lower lid fornix and its flora, might be suspected to allow rapid retrograde invasion of infective agents, resulting in endophthalmitis. In this series of KPro patients, however, the incidence of severe infection was very low, in fact comparable to that after standard trabeculectomy.

Retinal detachments after Boston Keratoprosthesis: incidence, predisposing factors, and visual outcomes

“…RPM formation, another predisposing factor to RD in our series, has also been attributed to inflammation 14 and associated with autoimmune disease. 15,16 We have demonstrated a strong correlation among the 3 factors most strongly associated with RD after KPro: sterile vitritis, RPM formation, and history of autoimmune disease. Accounting for these correlations, sterile vitritis and indication for surgery (autoimmune vs local disease) appear to be the only factors strongly predictive for development of an RD.…”

“…3,7,16,17 This can be performed before, during, or after implantation. Our study indicates that this can predispose to RD ( Figure 2); nevertheless, there is usually no choice but to proceed with the shunt in patients with recalcitrant glaucoma after KPro.…”

The Boston keratoprosthesis 2014: a step in the evolution of artificial corneas

“…One device, based on ferromagnetic principles and responding to both opening pressure and closing pressure, presently is being developed and tested [60]. In the severest cicatrizing situations, aqueous may have to be shunted to lower lid fornix or to one of the sinuses, thus to atmospheric pressure outside the eye [36]. This principle is surprisingly safe against infection and it might also be applicable in extremely dry eyes where aqueous shunted to the lower lid fornix can serve as "tears" [30].…”

“…Since then, faculty members, plus generations of fellows at the Massachusetts Eye and Ear Infirmary (MEEI)/Harvard Medical School have continued to try to create somewhat of a scientific basis for future refinements. Some metrics: 36 Type I and the rest Type II (see below). Worldwide about 11,000 B-KPros have now been used in over 50 countries.…”

Boston type I keratoprosthesis: Review

“…Considering that standard glaucoma shunts are often susceptible to capsule fibrosis obstructing the tube flow, efforts have been made to produce modified tube devices, such as Ahmed valve shunts to divert aqueous humor to alternative epithelialized cavities (lacrimal sac and ethmoid sinuses) where an obstructing capsule is less likely to form obstructing the flow and consequently increasing the intraocular pressure (38) . Randomized studies with longer followup, though, are necessary to address con cerns about a possible increase incidence of infectious complica tions and hypotony in theses modified drainage devices.…”