Keratoconus is caused by a progressive weakening of the generally strong corneal collagen within the stroma. As this collagen becomes unstable, the internal pressure within the eye can cause the cornea to bulge outward. As the cornea stretches and changes shape, the optical quality of vision degrades resulting in poor acuity. Keratoconus is often associated with other systemic collagenous diseases.
Recent treatments are beginning to explore ways of strengthening the cross-linking of corneal collagen. One topical treatment utilizes riboflavin and ultraviolet (UV) light exposure. The treatment of keratoconus shows promise as a safe, effective, simple, and inexpensive non-surgical treatment for keratoconus. Generally it is combined with surgical treatments, such as intacs for keratoconus, in order to provide an overall strengthening of the corneal collagen system.
Studies using riboflavin and ultraviolet treatment have generally had positive results and some signs that it either slows or prevents the progression of keratoconus. Some studies indicate that successful treatment can prevent keratectasia, the bulging of the cornea caused by the weakening of the collagen bindings during keratoconus.
Some studies even claim that through improvement of corneal collagen cross-linking vision can be substantially improved.
Other doctors remain skeptical, saying that cross-linking is not a popular belief in ophthalmology and that its effects are relatively unknown. So far it is relatively recent and few patients with keratoconus have been treated so results of collagen strengthening is not heavily documented.
It is likely that further study of riboflavin treatment and other similar keratoconus treatments upon the collagen within the cornea can provide increased understanding of the mechanisms of keratoconus. Current riboflavin treatments require office visits of 30 minutes that are repeated. During these visits riboflavin is applied to the corneal collagen and ultraviolet light is used to activate the solution.
This treatment is not yet FDA approved though it is used in Europe and other foreign countries.