Keratoconus is a progressive condition of the eye that causes the cornea (The clear front surface of the eye) to thin and distort in shape. A normal cornea has a regular dome-like shape but keratoconus causes the thin central area to protrude outward. This protrusion to the front of the cornea causes it to take on a cone shape giving the condition its name. It is this cone shape that leads to the distortion to vision. Keratoconus can be treated in a variety of ways including glasses cross linking, corneal implants and in the worst cases may require corneal grafts.
How does it occur?
While keratoconus has been known and studied for over 200 years the specific cause is not yet fully understood. It is usually an inherited corneal disorder, often in an autosomal dominant fashion. This means that approximately 50% of family members may end up with it. But it can also be random with no other family members affected. It affects men and women in equal proportions and is bilateral in 90% of patients.
Keratoconic eyes lack the ability to self-repair routine damage easily repaired by normal corneas.Keratoconic corneas are more susceptible to damage caused by minor trauma such as eye rubbing.
Who can get keratoconus?
The majority are affected by keratoconus in mid teens to early twenties but there are cases reported in people aged 40 or 50. Discovery of keratoconus usually occurs once the condition has progressed significantly enough to have an effect on vision but advances in testing methods have increased rates of early discovery.
It has been suggested by some studies that genetics are a factor in the development of keratoconus with around 15% of patients having a family member with the condition. The chance of a Keratoconic patient’s children to develop the condition is around 10%. While the exact cause is not known many suffers also experience allergies and eczema and there is a high occurrence of eye rubbing.
Treatment options for keratoconus?
In the initial stages of keratoconus most patients find that glasses or contact lenses correct their vision highly without issue. However, if the condition is progressing and regular updates to a spectacle correction are required then it is worth considering further treatment options. Corneal collagen cross linking is a process used to strengthen the cornea and halt any further progression of the condition. It works by soaking the cornea in a riboflavin solution that contains vitamin B and exposing the eye to ultraviolet radiation. The UV light activates the riboflavin and encourages the creation of collagen bonds, or cross links. These bonds are responsible for preventing the cornea from protruding further.
Cross linking: is not a cure for keratoconus and glasses or contact lenses would still be required after the procedure. However, it is a proven method to halt any progression of keratoconus and prevent any further loss of vision or the need for corneal transplant.
In cases where patients are no longer able to get good visual outcomes from glasses or contact lenses the option of intra-corneal ring segments (Kerarings) may be considered. The Keraring procedure has the goal of improving visual acuity by flattening the bulge of the cornea making the corneal surface more regular to improve quality of vision reduction of myopia and astigmatism Improving the tolerance and comfort of contact lens wear The ring segments are implanted into the body of the cornea to support and reshape the corneal surface. This treatment is often done in conjunction with corneal cross linking.
Corneal graft for very severe cases of keratoconus the above treatments may not be an option due to the progressive thinning of the cornea. For the most advanced cases it may be necessary to have a corneal transplant. While corneal transplantation has a high level of success it is a highly invasive procedure with potential risks including transplant rejection. Corneal transplantation also has a long recovery of one year or longer and the majority will still need glasses or contact lenses after the procedure.
How do I know if I have keratoconus?
Topography, Orbsacn and Pent cam which accurately determines the (shape and thickness) of the cornea allow us to screen for any potential Keratoconic changes to the eye.