Re: Is it possible to produce artificial corneas or retinas?

Dear Berkay,

Yes it is possible to produce artificial cornea. It is also possible to 
surgically implant a human cornea taken from a cadaver. This corneal 
grafting (keratoplasty) works relatively well but may lead to some 
problems such as rejection due to the poor vascularisation of the diseased 
cornea. That’s why artificial cornea or “hybrid” cornea (containing both 
biological and artificial components) seems to be a very encouraging 
alternative and is constantly improving (3). Another technique that seems 
very promising is to use genetically modified human cells grown on a 
collagen frame closely resembling human connective tissue (2). On the 
other hand, producing a complete artificial retina is illusive to my 
opinion since it is made of neuronal tissue that contain many types of 
neurons including ganglion cells which axons form the optic nerve that 
project to the brain. However, it may be possible to implant artificial 
devices at the first stages of retinal processing, i.e. at the level of 
photoreceptors. This interesting device, a silicon microchip 2mm in 
diameter, contains many microscopic solar cells that convert light into 
electrical impulses. The basic idea is that “current generated by the 
device in response to light stimulation will alter the membrane potential 
of overlying neurons and thereby activate the visual system.” (1). 
Although (to my knowledge) it remains to be demonstrated that such 
functional connections will indeed take place, I believe that this is a 
very interesting area of research.

Regards,
Eric

1. Peachey NS, Chow AY.
Subretinal implantation of semiconductor-based photodiodes: progress and 
challenges.
J. Rehabil. Res. Dev. 1999 36:371-6.

2. Griffith, M. et al.
Functional Human Corneal Equivalents Constructed from Cell Lines
Science 1999, 286: 2169-2172

3. Legeais JM, Renard G.
A second generation of artificial cornea (Biokpro II).
Biomaterials 1998 19:1517-22