Keratoconus is a non-inflammatory eye condition in which the normally round dome-shaped clear window of the eye (cornea) progressively thins causing a cone-like bulge to develop. This eventually impairs the ability of the eye to focus properly, potentially causing poor vision. The term Kerato-CONUS simply implies that the cornea changes shape to become conical.
Depending on ethnicity, keratoconus affects up to one in 450 people. It is more common in non-caucasians. It is usually diagnosed in young people at puberty, in their late teens or early twenties.
The exact cause is unknown. It is believed that genetics and environmental factors play a role. It is not generally considered an inherited disease, although rarely in some families more than one individual can be affected.
Early stages of keratoconus are detectable by an eye care practitioner. Edgbaston Eye Clinic boasts various ophthalmic diagnostic instruments for the detection and monitoring of keratoconus. Vision is often unaffected in the very early stages. It is important to remember that keratoconus doesn’t cause sudden loss of sight. If left unchecked, further changes in shape, thinning of the cornea and in advanced stages, scarring can cause loss of transparency of the cornea which impairs the ability of the eye to focus properly. Even in advanced keratoconus however it is usually possible to correct vision with highly specialised contact lenses. Edgbaston Eye Clinic is vastly in this field.
In the early stages, glasses or soft contact lenses may be used to correct vision. As the cornea becomes thinner and steeper, soft or specialist rigid gas permeable (RGP) contact lenses are often required to correct vision more adequately. In very advanced cases, where contact lenses fail to improve vision, a corneal transplant may be needed. This type of intervention is now rare since the introduction of ‘Cross-Linking’ (CXL). CXL is a relatively new treatment that can stop the disease getting worse. It is effective in over 94% of patients with a single 30minute outpatient procedure. CXL works best in the early stages of keratoconus.
Keratoconus does not require urgent referral since changes caused by the condition usually take several months or even years to develop. We therefore monitor those with the condition and invite them back for repeat assessments for up to five years from their initial visit. Each time you attend Edgbaston Eye Clinic for your keratinous monitoring, we will perform many of the same tests, including:
We will then compare these results with those from your previous visits. If any of the results show deterioration, we will discuss with you whether CXL is required.
CXL is only suitable where the corneal shape is continuing to deteriorate. This will be detected at your appointments. Beyond a certain stage however, if the cornea is too thin, it could be unsafe to perform the procedure. Usually in people in their late 30s, the corneal naturally stiffens and CXL is generally not required. Below this age, the cornea is more flexible and disease progression and worsening vision are more likely, although not certain, to occur.
Keratoconus gets worse because the cornea weakens. CXL uses ultraviolet light and vitamin B2 (riboflavin) drops to stiffen the cornea. Used together, they cause the fibers within the cornea to cross-link or bond more tightly, once the term cross-linking. This treatment mimics the normal age-related stiffening of the cornea, which is known as natural cross-linking.
CXL is performed as a day case procedure. The procedure takes about 30minutes. During the procedure, you will be asked to lie flat on the treatment table. Anaesthetic drops are used to numb the surface of the eye before a small clip is placed to keep your eye lids open. The outer surface of the eye is gently brushed clear and riboflavin drops are applied every few minutes for at least ten minutes. Following this, the ultraviolet light is shone at your eye for 8minutes. A soft bandage contact lens is then placed on the eye at the end of the procedure.