A process is described for changing the curvature of the cornea in which the light of a light source is focused in the cornea with a wavelength of approximately 1.5 .mu.m to 6 .mu.m so that the collagenic tissue shrinks selectively. The invention is characterized in that the light is applied continuously at such a power that, although a temperature is reached which leads to irreversible coagulations of the collagenic tissue, the temperature within the coagulated region rises to values at which there is not yet a relaxation of the tissue.
This invention relates to a contact lens made of donor corneal tissue, to a method of preparing that lens, and to a technique of placing the lens on the eye. The lens is made of donor corneal tissue that is acellularized by removing native epithelium and keratocytes. These cells are replaced with human epithelium and keratocytes to form a lens that has a structural anatomy similar to human cornea. The ocular lens is used to correct conditions such as astigmatism, myopia, aphakia, and presbyopia.
This relates to a lens made of donor corneal tissue suitable for use as a contact lens or an implanted lens, to a method of preparing that lens, and to a technique of placing the lens on the eye. The lens is made of donor corneal tissue that is acellularized by removing native epithelium and keratocytes. These cells optionally are replaced with human epithelium and keratocytes to form a lens that has a structural anatomy similar to human cornea. The ocular lens may be used to correct conditions such as astigmatism, myopia, aphakia, and presbyopia.
These methods, devices, and structures are useful in the field of ophthalmology; the devices and methods relate variously to separating or lifting corneal epithelium from the eye preferably in a substantially continuous layer, placing a lens or other suitable ocular or medical device beneath the epithelial membrane, and to the resulting structures formed by those procedures. The de-epilthelialization devices generally utilize a non-cutting separator or dissector that is configured to separate the epithelium at a naturally occurring cleavage surface in the eye between the epithelium and the corneal stroma (Bowman's membrane), specifically separating in the region of the lamina lucida. The separator or dissector may have a structure that rolls or vibrates (or both) at that cleavage surface or interface during the dissection step. The separated epithelium may be lifted or peeled from the surface of the eye to form an epithelial flap or a pocket. The epithelium may then be replaced on the cornea after a refractive procedure or after placement of an ocular lens (or other subepithelial device) on the eye. The subepithelial device may comprise a wide variety of synthetic, natural, or composite polymeric materials. The step of replacing epithelial tissue upon the subepithelial device or upon the anterior corneal surface promotes epithelial healing.
A device is disclosed for separating the epithelial layer of a cornea from the eye. The device includes a separator having an edge to remove the epithelial layer as the separator moves across the eye. The edge includes a thickness thicker than the thickness of at least one epithelial cell and less thick than the thickness of the epithelial layer. Separation can be performed mechanically, without the use of chemicals, so that the shape and integrity of the separated epithelial layer is preserved. The device can also be used with a polymer film that adheres to the epithelial layer to help preserve an integrity of the epithelial layer.
