gms | German Medical Science

Objective: Corneal opacity is a leading cause of reversible blindness worldwide. Current treatments such as corneal transplantation and keratoprosthesis have fundamental limitations (i.e. 13 million remain on corneal transplant waitlists). An electronic display based corneal visual prosthesis placed within the eye (intraocular projector) can project visual imagery onto the retina and potentially allow for high quality vision without need for corneal clarity. While this technology has similarities to retinal prostheses, it treats a different group of patients.

Materials and methods: Four complete and functional intraocular projection systems were constructed from commercially available microdisplay and electronic components and encased in biocompatible plastic housing. They consist of an intraocular projector unit attached to an extraocular processing unit. They were tested for optical properties, biocompatibility, heat dissipation, waterproofing and accelerated wear. A surgical implantation technique was developed.

Results: Intraocular projectors were produced of a size that can fit within the eye. Their optics produce better than 20/200 equivalent visual acuity. Their weight is similar to that of a crystalline lens. MTT assay demonstrated no cytotoxicity of devices in vitro. Temperature testing demonstrated less than 2 C increase in temperature after one hour. 3 devices lasted over 12 weeks under accelerated wear conditions. Implantation surgery was demonstrated via corneal trephination insertion in a cadaver eye.

Conclusion: This is the first study to demonstrate that fully functional intraocular projection systems can be made with currently available components. This technology has the potential to be an important new way of treating of corneal blindness.

This research is supported by the U.S. National Eye Institute (K08EY027459) and the U.S. Department of Defense (VR 180058)