It’s world keratoconus day. What do you know about keratoconus?
The anterior portion of the eye is bounded by a thin transparent structure called the cornea. The cornea is responsible for two-thirds of the refractive power of the eye and is important for clear vision.
Keratoconus occurs when the cornea progressively thins and bulges out. Usually both eyes are affected; however, one eye may be more affected than the other.
Research shows that keratoconus affects at least 1 in 2,000 people and onset is in the early teenage years and can proceed up to the third decade of life.
Signs and symptoms
Individuals with keratoconus usually complain of blur vision at all distances (which may resemble the common complaints of normal refractive cases, making a diagnosis of keratoconus difficult to make especially in early stages), sensitivity to light, glare, frequent spectacle prescription change, double vision in one eye (monocular diplopia) and poor night vision.
Causes and risk factors
The exact cause of keratoconus is largely unknown, but certain predisposing factors have been known to be associated with the disease and these include:
- A family history of keratoconus (genetic factors)
- Allergies and rubbing of the eyes (environmental factors)
- Genetic diseases such as Alport syndrome, Down’s syndrome, Marfan’s syndrome
Generally, the mechanism behind the development of keratoconus lies in the anatomical changes of the cornea to a cone shape as seen in the diagram below.
Diagnosis of Keratoconus
Diagnosis of keratoconus is made after thorough examination by a trained eye care professional. The examination and assessment includes visual acuity, refraction, slit lamp biomicroscopy evaluation, corneal topography and pachymetry.
Management of Keratoconus
The management of keratoconus borders around two main goals
- Providing clear vision
- Slowing or halting the progression of keratoconus
In the early stages of keratoconus, regular glasses or soft contact lenses may improve vision but will not give clear vision as the disease progresses into the moderate to advanced stage. In the moderate to advanced stages of Keratoconus most patients will require management with special contact lenses like rigid gas permeable corneal or scleral lenses (RGP), piggyback or hybrid contact lenses.
In cases where keratoconus continues to progress despite treatment of allergies and avoiding eye rubbing, a surgical procedure called Collagen cross linking is performed to decrease or stop the progression of the disease.
However, in a state where the keratoconus has progressed to a very advanced stage which has resulted in scarring and inability of the patient to tolerate contact lenses, corneal transplantation is required to remove the diseased tissue. Patient may then opt for contact lenses or spectacles after corneal transplantation is done. Newer surgical techniques such as corneal intrastromal ring segment implantation can flatten the bulgy cornea and may be combined with collagen cross linking to improve vision and improve contact lens fitting after the surgical procedure.
As the world marks World Keratoconus day today, learn more about the disease and if you know anyone who may be suffering from the condition, book an appointment with us to get their eyes evaluated.