According to consultant eye specialist Daniel Mundia, research shows that the primary cause for keratoconous is the weakening of the cornea leading to thinning, which causes it to bulge and be further damaged. When this happens, an individual may need a cornea transplant.
The cornea is the transparent cover of the eye that functions like a window to control and focuses the entry of light. In a cornea transplant, surgery is performed to remove all or part of a damaged cornea and replace it with healthy donor tissue. "The disease commonly runs in families although other causes include overexposure to ultra-violet light, which includes direct sunlight, eye rubbing and allergic eye conditions. Down syndrome, poorly fitting contact lenses and chronic eye irritation may also cause damage to the cornea," notes Mundia.
In diagnosing the condition, Mundia says that the curvature and thickness of the cornea is measured. "The more curved the cornea, the higher the likelihood of having keratoconus, and the thinner the cornea the higher the likelihood of the disease," Mundia notes, adding that the availability of newer and more advanced methods involve machines that check for all these parameters much quicker.
The initial effect of a curved cornea is short sightedness but Mundia warns that over time it leads to distortion of images causing the patient to have very poor vision. "The continued bulging may also lead to internal tearing of the cornea, which causes sudden swelling and whitening of the cornea leading to pain, severe loss of vision and even though the swelling will go away, it could leave a dense central white scar that may render the eye blind," Mundia warns.
For treatment, the first approach is to prescribe spectacles to correct the poor vision but with time rigid contact lenses become necessary. Cornea transplants are usually at the tail end of treatment.
There is another form of treatment called collagen cross-linking, Mundia says. In collagen cross-linking, Vitamin B2 is added to the corneal tissue using ultraviolet light to strengthen it and prevent further deterioration.
In Kenya, corneal transplantation is available at the P.C.E.A Kikuyu Eye Unit, Lions Sight First hospital in Loresho, Aga Khan University Hospital, Nairobi and Tenwek Mission Hospital.
"The cost of corneal transplant is still high and unavailable to most needy cases as the tissues have to be imported from the US. It would help very much if we had cornea banks locally," Mundia says.
