Keratoconus arises because of weakness in the layers of the cornea that leads to progressive thinning of the cornea. Normal pressure within the eye causes the cornea to progressively bulge into a cone-like shape making it more myopic and inducing astigmatism (think of the cornea becoming shaped more like a rugby ball than a football). This is noticed as increased blurring of vision and more frequent changes in spectacle prescriptions. Normal activities such as driving and reading can be difficult to perform.
There are other forms of corneal weakness that can be treated in similar ways to kerataconus. Examples include Pellucid Marginal Degeneration (PMD) and Corneal Ectasia that may occur after laser refractive surgery.
Keratoconus normally affects both eyes, although at differing points of onset and rates of progression. In most people keratoconus begins during their teenage years and progresses at varying rates until stabilising in their 30s or 40s. Keratoconus is normally treated with contact lenses to improve vision. A proper lens fit is crucial to obtain adequate vision and wearing comfort. Poorly fitting or outdated contact lenses can be uncomfortable and lead to significant discomfort, corneal abrasions, scarring or infection.
Although keratoconus rarely results in total blindness, 20% of all patients may at some time need to undergo a corneal transplant if the condition is left untreated. This can be either because of corneal scarring that prevents useful vision, or because of intolerable side effects related to use of contact lenses.
However, corneal transplantation is a major undertaking with a prolonged recovery time. Although the final result is often favourable in keratoconus, it should be considered a last resort.
Fortunately, there are two new methods to treat keratoconus that are much less invasive than a corneal transplant: INTACS IntraCorneal Rings, and corneal collagen crosslinking (CXL).
Treatment of Keratoconus
Many patients get in touch with us asking for a certain treatment, but it is clear from the following list of treatments for keratoconus that the correct approach depends on many factors. A full consultation with the consultant will be required to establish the precise clinical need and most appropriate care plan to produce the best outcome.
Treatment of keratoconus is aimed at:
1.Stabilising corneal shape
- Corneal Collagen Crosslinking (CXL) Read More
When corneal shape is only mildly affected in early keratoconus, and the vision is still good, CXL can halt progressive distortion of the cornea by increasing its strength.
2. Improving vision
- Glasses and contact lenses
These are the traditional methods for restoring vision. Where this is
not possible, the interventions described below are successful in a high proportion of patients.
- Intrastromal Corneal Ring Segments (ICRS) Read More
When corneal shape is more distorted and the vision is reduced, ICRS can re-shape the cornea and restore vision.
- Implantable Collamer Lens (ICL) Read More
When corneal shape is stable, corrected vision is good and there is a desire to reduce dependence on glasses, then ICL phakic lens implantation can provide functional visual rehabilitation.
3. Combining treatments
- ICRS + CXL
In some cases there is a need to re-shape the cornea and increase corneal strength. This produces a normalisation of corneal shape that is long-lasting and stable.
- Additional ICL thereafter
When the cornea has undergone re-shaping and become stable, ICL implantation can complete the visual rehabilitation by improving functional vision.
- Corneal transplantation Read More
In advanced keratoconus with corneal scarring none of the above treatments is applicable. A corneal transplant, either full- or partial-thickness, can restore corneal clarity and improve vision.