The cornea is the outermost layer of the eye, which protects and covers the front of the eye. It is a transparent, highly organized group of cells and proteins. The cornea contains no blood vessels since it must remain transparent, and instead receives its nourishment from tears and the aqueous humor (thick, watery substance), which is behind it in the eye. The cornea has two main functions, the first is to protect the rest of the eye from bacteria, dust, water and other potentially harmful objects. The second is to act as the outermost lens—controlling focus and the entry of light into the eye.
Injuries to the Cornea
There are a variety of ways the cornea can be injured: disease, foreign objects (metal and wood fragments, etc.) and intentional injuries, such as laser surgery. Shallow injuries, such as small particles in the eye, only scratch the outer layer of the cornea, and are often dealt with quickly by the cornea’s repair systems. With these shallow injuries, fibrotic “repair tissue” slides over to cover the wound before it can get infected or vision can be affected. If an injury penetrates deeper into the cornea, it can take longer to heal and cause scar tissue to form, impairing vision.
There are, on average, 54,280 yearly eye injuries reported in the manufacturing, mining and agricultural industries in the U.S. alone. In the military, eye and face injuries occur at four times the rate of torso injuries. Moreover, eye injuries are the second most common injury sustained by U.S. soldiers in the war in Iraq and Afghanistan. It has been estimated that in developed countries the rate of penetrating eye injury is 3.6 per 100,000 in population. With a US population of roughly 300,000,000 approximately 10,800 annually will likely have their sight lost or compromised by penetrating eye injuries.
Corneal Ulcers
A Corneal Ulcer is a disruption (usually an erosion or open sore) on the epithelial (outer layer) of the Cornea. They can be infectious or non-infectious. Corneal Ulcers are most often caused by infections, including bacteria, viruses, fungi or parasites. They can, however, sometimes be the result of abrasions, severe dry eyes, severe allergic eye disease, foreign bodies in the eye and various inflammatory diseases.
It is estimated that there are approximately 72,500 cases of corneal ulcers annually in the US. In such medical cases, the number of Europeans with a given ailment will usually be roughly 1.5 times that of the US. Estimates of the Asian and the Indian subcontinent are less accurate. In India alone, it has been estimated that there are 840,000 cases of corneal ulcers annually, many a secondary result of trauma. As a result, the number of corneal ulcers worldwide is likely somewhere in the 1.1 to 1.5 million range. Roughly 235,000 to 300,000 cases annually are in industrialized nations.
Corneal Transplants
When the cornea becomes cloudy, light cannot penetrate it to the light-receptive retina. Vision loss or blindness can occur. A corneal transplant involves removing the cloudy part of the cornea and replacing it with a new, clear cornea (usually donated through an eye bank). The new cornea is secured with a fine thread which can remain in the eye for months of even years. Following surgery, eye drops are required for several months to help promote healing. There are approximately 45,000 corneal transplants a year.
TheraKine's EpiKine™ is targeted to facilitate quicker, more predictable healing after corneal injury and corneal transplantation.
For more information on corneal injuries, its treatment and prevention, see:
National Eye Institute's page on Corneal Injury