Keratoconus is a relatively rare pathological condition, which causes the corneal surface (the front of the eye), to begin to grow forward and take up a conical shape (a bit like an ice cream cone) rather than normal spherical curve. This leads to distorted vision and, if the progression of this shape change is not physically halted, it can ultimately lead to the rupture of the cornea and subsequent blindness. If the problem gets to such a position a corneal graft may be necessary but the visual results may not be good.
KERATOCONUS
A typical "conical cornea"
Correction of keratoconus with spectacles is not effective since we are technically unable to create the curves on the spectacle lens that will focus light correctly upon the retina at the back of the eye - at best the vision may be better but still very distorted! Furthermore if glasses are prescribed then, bearing in mind this condition is continually changing, frequent alterations to the spectacle prescription will be needed making for increased costs.
The most frequent method therefore of controlling keratoconus is the use of rigid Contact Lenses to exert a positive pressure over the apex of the cornea to hold the cornea in a predetermined shape of the Contact Lens. The lenses used to correct this are generally Flexible Oxygen Permeable designs which are relatively small and fit between the eyelids.
When these fail to produce the best results we may recommend a 'piggy back' system - a soft lens with a rigid lens on top or, alternatively SCLERAL LENSES. First fitted in the 1880's made from glass these have now graduated to being made in highly oxygen permeable plastics. See www.sclerals.com/what.html
  
In recent years specialist Soft Lenses have become available which also have a good controlling effect on the eye shape.
Although we can never effectively make the cornea totally spherical by using Contact Lenses the tear lens created between the back of the Contact Lens and the front of the cornea helps considerably in reducing the distortion which would be apparent with a spectacle correction. At www.kerasoft3.com you'll find more about one silicone hydrogel we fit.
Correction of Keratoconus requires the skill of an expert Contact Lens Practitioner but our results are such that many Keratoconic patients fitted with Contact Lenses are able to achieve vision up to and above that required to read a number plate at 25 yards. In other words making the difference between being able to drive or not.
Keratoconic patients with well fitted Contact Lenses, if regularly monitored by anexperienced Contact Lens Practitioner, should expect to enjoy good stable vision. As a specialist practice we regularly receive referrals from colleagues of the more complex patient such as keratoconics.
If Contacts fail a relatively new treatment is being pioneered in some specialist centres called COLLAGEN CROSS LINKING - see Collagen Cross Linking Info .
For even more about KERATOCONUS see
www.wikipedia.org/wiki/Keratoconus www.keratoconus-group.org.uk
www.kenpullum.co.uk
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