Design of a Biomimetic Vitreous Replacement Tamponade for Retinal Detachment

Baker 1, 2 ;  Ballios 2 ;  Ing 2 ;  Ganya 3 ;  Yan 3 ;  Cooke 2 ;  Devenyi 3 ;  Shoichet 1, 2 ;

1. Department of Chemical Engineering and Applied Chemistry, University of Toronto; 2. Institute of Biomaterials and Biomedical Engineering, University of Toronto; 3. Toronto Western Hospital

The incidence of retinal detachment (RD) in the population is between 6.3-17.9 per 100,000. In severe cases to re-attach the retina patients must undergo a pars plana vitrectomy to remove the vitreous of the eye, and replace it with an intraocular tamponade. The most common tamponades currently used are gas and silicone oils such as Densiron®. Gas tamponades may limit the patient from air travel, and require face-down positioning in cases of inferior detachments but have the advantage of being spontaneously resorbed. This has led to the development of heavier than liquid replacements that do not degrade, can result in ocular hypertension and often require removal with an additional surgery. Natural biomaterials such as hyaluronan and collagen have been explored as alternatives for retinal tamponade but often require crosslinking but to date all have shown limited stability and often have lower densities than water.
We have developed a rapid crosslinked hydrogel with a refractive index similar to native vitreous 1.3681 ± 0.004, and initial tamponade density 1.119 ± 0.012 similar to that of Densiron 1.079 ± 0.008 g·cm-3. The tamponade has shown sustained stability >4 weeks by swelling studies and was cytocompatible with retinal pigmented epithelial cells over 48 h. Initial biocompatibility studies with New Zealand White rabbits at days 1, 7 and 28 showed no significant increases in ocular pressure. Future studies will focus on long term stability in vivo prior to direct comparison with Densiron to flatten induced retinal detachment at 1, 7 and 28 days.