In vivo feasibility study of a novel critical hydrogel as an artificial vitreous body using rabbit eyes

Abstract

Purpose : An ideal artificial vitreous body should at least meet 3 demands: the restricted osmotic pressure, adequate elastic modulus, and low cytotoxicity, which were not fulfilled in the previously developed ones. We designed and fabricated a new class of safe in-situ forming hydrogel (critical hydrogel) with an extremely low polymer content in order to achieves all three demands for artificial vitreous body. The critical hydrogel can be injected through needle as solution, and becomes gel state in appropriate time scale for surgery (1 ~ 15 min). This in vivo study was conducted to examine feasibility of the critical hydrogel as an artificial vitreous body using rabbit eyes.

Methods : A 25-gauge vitrectomy was performed in the left eyes of 7 rabbits. After removal of the vitreous with a vitrectomy cutter, air-fluid exchange was performed in the vitreous cavity. Following air–fluid exchange, the critical hydrogel was injected into the vitreous with a 27-gauge needle. Intraocular pressure, ophthalmologic examination, and optical coherence tomography (OCT) were carried out at 3, 7, 28, and 150 days postoperatively. Bilateral electroretinograms (ERG) were recorded simultaneously 150 days postoperatively.

Results : No elevation of intraocular pressure was observed throughout the observation period. Based on slit-lamp examinations and fundus photography using indirect ophthalmoscopy, no retinal detachment, significant inflammation, toxic reaction, vitreous haemorrhage, retinitis, or endophthalmitis was observed. The OCT revealed no retinal detachment or retinal edema, and the retinal microstructure was not morphologically damaged. The critical hydrogel remained transparent throughout the follow-up period in vitreous cavity of all eyes. ERG showed typical patterns, and no apparent difference was observed between both eyes of the rabbits.

Conclusions : The critical hydrogel was found to be applicable as an artificial vitreous body within the modality of present small gauge incision vitreous surgeries.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.