Keratoconus is a bilateral progressive disorder of unknown cause that typically starts during adolescence. It is usually an inherited corneal disorder which means that approximately 50% of family members may have it.
Cornea is the clear outer surface of the eye that permits light to enter the eye & focus on the retina. The cornea consists of finely arranged layers (lamellae) of connective tissue called collagen that make up to 90% of its substance. The chemical bonds (cross links) in between these layers get weaker in keratoconus leading to progressive thinning and stretching of the cornea. Normal pressure within the eye causes the cornea to bulge forward into an irregular cone shape.
In early stages of keratoconus, Rigid gas permeable contact lenses can be tried. But in progressive cases, corneal collagen cross-linking is the treatment of choice.
CORNEAL COLLAGEN CROSSLINKING WITH RIBOFLAVIN (C3-R)
A new non surgical, non invasive treatment, based on collagen cross linking with Ultraviolet A (UVA, 365nm) and riboflavin (Vitamin B 2), a photosensitizing agent is now available. This changes the intrinsic biomechanical properties of the cornea, increasing its mechanical strength. This increase in corneal strength has shown to arrest the progression of keratoconus.
The treatment is performed in operation theatre under complete sterile conditions. Usually one eye is treated in one sitting. The treatment is performed using anesthetic eye drops. The surface of the eye (cornea) is treated with application of Riboflavin eye drops for 30 minutes. The eye is then exposed to UVA light for 30 minutes. Hence, the treatment takes about an hour per eye. After the treatment, antibiotic eye drops are applied; a bandage contact lens may be applied, which will be removed during the follow up visit.
However one need to understand that Collagen cross-linking treatment is not a cure for keratoconus, rather, it aims to slow the progression of the condition. However following the cross-linking treatment it makes the patient more comfortable to wear contact lens. The main aim of this treatment is to arrest progression of keratoconus, and thereby prevent further deterioration in vision and the need for corneal transplantation.