While electronic eyeballs may eventually be a solution to restore sight for the visually impaired, or even to enhance vision for those with normal eyesight, they still are very crude and may have a long way to go. In a classic race between electronics and biotechnology, it appears that biotechnology may have caught up with an incredible solution to restoring vision.
Scientists and the University of New South Wales in Australia cultured corneal stem cells on extended wear contact lenses. They then cleaned the corneas of three patients -- two of whom were legally blind and one with limited vision (they could read the biggest row of the vision chart) -- and had the patient start wearing the lens.
Amazingly, within 10 to 14 days the stem cells had reentered the cornea and began to recolonize it. UNSW’s Dr Nick Di Girolamo describes, "The procedure is totally simple and cheap. Unlike other techniques, it requires no foreign human or animal products, only the patient’s own serum, and is completely non-invasive."
The two legally blind patients can now read the top row of a vision chart, while the vision impaired patient can read enough of the chart to get their driver's license.
The technique still has unknowns. While the patients have regained vision, lasting for over 18 months, there's a chance the gains won't last. While the cornea has no blood supply and gets its oxygen from the air, but it remains to be seen whether the blind patient's tear fluid is sufficient to sustain the new eye tissue in the long term.
Still, Dr. Di Girolamo says the technique looks promising and holds promise even to patients with damage to both eyes. Dr. Girolamo states, "One of our patients had aniridia, a congenital condition affecting both eyes. In that case, instead of taking the stem cells from the other cornea, we took them from another part of the eye altogether – the conjunctiva – which also harbors stem cells."
Corneal diseases are a leading cause of blindness. According to the World Health Organization, damage to this delicate organ causes 1.5 million people to lose sight in one of their eyes every year.
The UNSW team is looking to expand the work to cover other types of ocular damage. Previous research by other teams has shown that stem cells could potentially be used to grow entire eyeballs. They also believe the technique could be applied to regrowing skin and other damaged tissues.
quote: Embryonic stem cells are known to easily form tetramers, and tumors at the site of injection -- that is, they begin to turn into multiple different tissues, not just the tissue wanted. Adult stem cells don't have this problem,as they are already prepared to only adopt the correct tissue type to do regeneration
quote: So then, the genetic dissimilarity with an embryonic stem cell and your own cells rises a plethora of issues. They may not respond to your body's signals the same way as the surrounding tissue, or even grow into the correct tissue model, which, again, results in cancer or aberrant tissue behavior. And with the threat of rejection always lurking around the corner, you also get the fun times of sparking auto-immune diseases.
quote: Perhaps if the reverse were true, Embryonic stem cells would be curing cancer by now.
quote: rejection being only one. From a biological standpoint I see fetal stem cell usage as a long and difficult road that may not be worth the time and effort.
quote: A damaged cornea is also BY FAR the easiest form of blindness to fix. It results from opacification of the cornea by protein denaturation or scarring or some other mechanical disturbance which reduces transparency. Fixing it is in principle barely more complicated than fixing a cataract.
quote: The only new concept was creating a cell scaffold in the shape of a contact lens so that corneal stem cells are in prolong contact with the cornea and have a chance to migrate in.