GLOBAL NEED & SOLUTIONS
One person every 20 seconds becomes blind or impaired due to corneal disease or injury. Only 1% of these patients would receive corneas due to donors’ shortage. That is why sight restoration through bioengineering by LinkoCare may help solve a global problem.
According to WHO’s 2010 report corneal blindness is the 2nd main cause of blindness worldwide accounting for 23 million patients (unilateral and bilateral) adding a huge burden to families, communities, and health care resources [1, 2]. Often the only treatment option is surgical transplantation of donor cornea, a therapeutic option that has been unchanged for more than 50 years and is limited by the huge shortage of suitable donor tissue and rejection. In India and China there are more than 2,000,000 people, in each country, with corneal diseases in need of cornea transplant. Clearly, there is an unmet need for an alternative. Prosthetic artificial corneas, cell-based therapies, and 3D scaffold-based therapies have been rigorously pursued but their clinical use has been limited due to challenges including: lack of integration into the surrounding tissue; limited cell sources and functionality; inefficient epithelial cell coverage and non-interaction with host cells, respectively.
A severe worldwide shortage of donor corneal tissue for transplantation, particularly in developing countries, and complications with prosthetic artificial corneas has prompted the advancement of bioengineered tissue alternatives. Therefore, bioengineered corneas such as those of LinkoCare with favorable biological and physical properties, which are additionally amenable to low-cost mass production, are in urgent need.
1. Pascolini D, Mariotti SP. Br J Ophthalmol. 2012;96:614–8.
2. Matthew S Oliva, Tim Schottman, and Manoj Gulati, Turning the tide of corneal blindness, Indian J Ophthalmol. 2012 Sep-Oct; 60(5): 423–427.
CORNEA ANATOMY & FUNCTIONS
Anatomy, Functions, and Main Diseases of the Cornea:
The cornea acts as a clear, transparent window at the front of the eye. The cornea is the only transparent tissue in the human body with a thickness that is approximately 0.52 mm centrally and 0.65 mm peripherally and its average horizontal diameter is about 12 mm. The cornea offers 75% of the refractive power of the human eye, allowing transmission of light through it to be focused onto the retina. As well as photo-protection, by significant absorbance of UV radiation, the cornea acts as a thick, elastic physical barrier protecting the internal ocular structures from outside insults, which may be physical, chemical or microbial. Furthermore, the cornea withstands changes in intraocular pressure (IOP) and curvature changes of the eye. Transparency is obviously essential to vision. It is the cornea’s complex multilayered structure that allows it to fulfill its functions. If the cornea is affected by diseases or external insults, it loses its transparency resulting in partial or full blindness.
CORNEAL TRANSPLANT SURGERY
A corneal transplant involves the surgical replacement of a diseased or injured human cornea with a healthy portion of a donor cornea or a bioengineered cornea.
The reason for blindness or low vision in injured or diseased cornea is that it interferes with the normal passage of light into the eye. The transplant of clear, healthy donor tissue restores the normal visual pathway. In recent years, corneal transplant surgery has advanced so that in many cases, only that section of the cornea that is diseased or injured is replaced. These procedures are referred to as “lamellar keraroplasty”. The LinkoCare bioengineered cornea can be used for “anterior lamellar keratoplasty” (ALK) or “deep anterior lamellar keratoplasty” (DALK). Anterior keratoplasty (ALK) replaces the superficial anterior section of the cornea while DALK replaces the entire stroma, or mid-section of the cornea. ALK or DALK is used to treat corneal conditions such as keratoconus, a disease where the cornea becomes cone-shaped and thins out resulting in impaired vision or blindness.
The medical term for a full thickness corneal transplantation is “keratoplasty”.