Abstract
Purpose :
Glaucoma drainage devices and minimally invasive glaucoma surgeries (MIGS) often present with tradeoffs in safety and durability of efficacy. Using a rabbit model, we examined the biocompatibility and feasibility of VisiPlate, a novel, ultrathin, tubeless subconjunctival shunt comprised of a network of microchannels.
Methods :
Six naïve female New Zealand White rabbits received a total of nine implants, each composed of a 400 nm thick aluminum oxide core and coated with 2 µm of parylene-C. Three rabbits were implanted in the right eye with the contralateral eye untreated and monitored for 93 days. Another three rabbits received devices in both eyes and were monitored for 180 days, with 100 μL of 0.2 mg/mL mitomycin-C (MMC) application in the right eye. The surgical procedure involved a 60-90° peritomy and a stab incision through the sclera into the anterior chamber, 2 mm from the limbus. Tonometry, slit-lamp exam, clinical exam, fluorescein patency testing, and histopathology were performed.
Results :
VisiPlate demonstrated statistically significant (p<0.05) intraocular pressure (IOP) lowering of 20-40% compared to baseline at each timepoint over the course of three months in the nine implanted eyes. All eyes developed blebs over the implant, and fluorescein testing demonstrated fluid patency at 22 days post-implantation. Slit lamp and clinical observations showed that VisiPlate was well tolerated, with low levels of conjunctival congestion, conjunctival swelling, aqueous flare, hyphema, and iris involvement from surgery that resolved over time. At sacrifice time points of 93 days and 180 days, the only notable observations were mild levels of conjunctival congestion in implanted eyes. Histopathology showed minimal tissue response and no obvious inflammation, fibrosis, or necrosis around the implant.
Conclusions :
The results of this in vivo study demonstrate the biocompatibility and IOP-lowering effect of a multichannel, ultrathin subconjunctival shunt in a rabbit model. The data suggest that VisiPlate may safely enhance aqueous outflow and significantly reduce intraocular pressure.
This is a 2021 ARVO Annual Meeting abstract.