Artificial Cornea Using New Biomaterials PD/PI Maxwell Maginness PhD Project Summary/Abstract. We propose to advance the development of a novel artificial cornea design enabled by a new biomaterial technology permitting facile integration and sclera tissue reconstruction. The design offers potential for an excellent visual outcome, stable and robust integration with the host tissue;is anticipated to overcome limitations of previous artificial cornea designs and does not require human donor tissue. Early animal studies also suggest that the design allows for a simple surgical implantation technique. The proposal is directed at the National Eye Institute Corneal Diseases Program under the """"""""development of new biomaterials for corneal prostheses"""""""" listing. The Medical Problem: Corneal blindness opacification of the transparent tissue covering the front of the eye is one of the two most prevalent causes of treatable blindness. It affects some 12 million people worldwide. [1] Corneal transplants with human donor tissue offer solutions for a fraction of patients with less severe disease, with approximately 100,000 such procedures worldwide every year. These procedures require the support of eye banks, not available in many world regions with a high incidence of blindness. In developed countries increasing numbers of LASIK procedures are rendering many potential donor eyes unusable. [2] The alternative is an artificial cornea (Keratoprothesis """"""""K-pro""""""""). There are two currently available FDA- approved devices - the Boston K-Pro [3] and the AlphaCor device [4]. These show poor integration with host tissue and require complex surgical implantation with lengthy follow-up. Presently they are offered only as a last resort in a few centers nationwide (University of Washington is one of them), leaving many untreated cases. Proposed Solution: Our proposed artificial cornea design aims to overcome these limitations a by combining: A clear, semi rigid optical center, proven to provide excellent and rapid visual recovery A porous periphery based on Spherically Templated Angiogenic Regenerative (STAR) biomaterial structure to rapidly achieve a robust, stable, well-integrated host tissue interface. Use of well proven biocompatible materials (silicones) with appropriate optical and mechanical properties for the entire artificial cornea device structure. No donor tissue required. Simple, one step surgical procedure. Originally developed at the University of Washington Engineered Biomaterials Laboratory under Dr Buddy Ratner, (mentoring this project) STAR [5] is a porous 3D biomaterial with a unique, tightly controlled geometry enhancing tissue attachment, in-growth and revascularization. The structure may be made from a variety of substrate materials, including biocompatible silicone rubbers as already widely used in other ophthalmic devices (e.g. glaucoma shunts, IOL's). Healionics Corporation holds exclusive license and is commercializing forms of the STAR material for a variety of medical applications. Preliminary studies with STAR biomaterial structures in the rabbit sclera have shown the rapid tissue integration and desirable reconstructive, vascularized, afibrotic healing patterns needed for a successful prosthetic cornea. The primary aim of this proposal is to extend and combine the biomaterials capability of Healionics Corporation with the in vitro and in vivo feasibility studies done by Dr. Ratner and Dr. Shen of UW Ophthalmology towards the next steps in developing an artificial cornea. The proposed developments of better construction methods, periphery tissue adhesion studies, durability testing and an extension of in vivo studies, are directed to this goal. The longer term aim is to refine the designs in the light of results obtained under this proposal, proceed to a more extensive study and eventually to human use. Keywords: Artificial cornea, porous biomaterials, treatable blindness, corneal transplant surgery.
Corneal opacity is a major cause of blindness. Use of donor corneas is not applicable for many cases and artificial corneas developed to date have shown serious limitations. The development of a new biomaterial structure with greatly improved sclera tissue integration and excellent optics shows potential to overcome many of these issues and allow construction and application of an improved prosthesis. Success with the steps proposed here may lead eventually to sight restoration covering a much wider population than is possible with present methods.
