Abstract
Purpose :
Age-related macular degeneration (AMD) is the leading cause of vision loss in the US affecting more than 10 million individuals. Advanced stage of AMD is initiated by atrophy of retinal pigment epithelium (RPE) and it is thought that RPE transplantation in the back of the eye can protect vision loss in AMD patients. Here we describe the design of surgical instrument for safe and reliable delivery of native tissue-like RPE implants on biodegradable substrate in the subretinal space.
Methods :
Laser induced RPE damage in a pig model was used to test the transplantation tool design. Instrument was tested after 25G core vitrectomy and HBSS+ induced retinal detachment. All surgical procedures were evaluated by imaging and functional evaluations using OCT and mfERG. At the end of the experiment the eyes were enucleated and processed for histology. Serial sections of implanted eyes were evaluated by light microscopy and immunostaining to determine success of implantation procedure.
Results :
Instrument design consists of hydraulically operated S-shaped and flattened cannula attached to a vitrectomy machine viscous fluid injection port where viscous fluid is replaced by a hyaluronic acid aqueous solution. Multiple tests confirmed that metal cannula with transparent and tinted plastic tip is best suited for atraumatic delivery of implants into subretinal space. This instrument accommodates 2 x 4 mm oval shaped native tissue-like implant. Implant viability was confirmed using mfERG and its anatomical integrity using OCT.
Conclusions :
Current instrument design provides excellent implant protection during surgery procedures and allows safe delivery of native tissue-like implants into the subretinal space with minimal trauma to surrounding tissues. Taking into account anatomical size similarity between pig and human eyes, this instrument can also be used in human eye surgeries.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.