What is Keratoconus?
Keratoconus is a progressive condition affecting the structure of the cornea, the clear front surface of the eye. The collagen structure of the cornea is defective resulting in the cornea becoming progressively thinner, causing it to bulge and form an irregular conical shape rather than a normal round dome shape.
Onset and diagnosis is usually made during puberty and later teenage years. Both eyes are generally affected at the same time but progression can often be asymmetrical, with one eye worse than the other. The degenerative process of keratoconus continues for 10-20 years following onset before naturally stabilising.
The exact cause of keratoconus is unknown but there are strong genetic links and it is believed that factors such as rubbing eyes and hot environments exacerbate the condition.
Signs of Keratoconus
The first signs of keratoconus tend to be blurred vision resulting from an increase in shortsightedness (myopia) and a increase or change in astigmatism. Patients may also notice reduced night vision, shadowing of objects, sensitivity to bright light and distortion around lights. In further progressed keratoconus, the conical shape of the cornea or bulging of the lower eyelids when the patient looks down (called Munson’s Sign) may be visible to the naked eye.
Treatment of Keratoconus
Mild cases may be managed with the use of soft contact lenses or glasses to correct refractive error but it is more common to require hard/rigid gas permeable contact lenses for best vision results.
More serious cases may require corneal rings(INTACS) to be inserted into the cornea to maintain the shape of cornea.
Corneal collagen crosslinking is a relatively new treatment method that involves the application of riboflavin to the stromal (middle) layer of the cornea and treatment with UVA light. This strengthens the bonds of the collagen strands in the stromal layer of the cornea in an attempt to halt or slow the thinning process keratoconus.
In very advanced cases a corneal transplant may required.