– Keratoconus –
Keratoconus is a condition that affects the cornea, the clear dome that covers the coloured part of the eye (or iris). This corneal disease causes thinning to this important tissue. When the tissue thins, the internal eye pressure causes the thinned section of the tissue to push forward, changing the corneal shape from round to coned. This is what the term “keratoconus” means, a conical cornea.
Correcting Vision in Eyes with Keratoconus
In the early stages of keratoconus, glasses can still be used to provide clear (if no longer crisp) vision. However, as the disease progress and the cone shape becomes more pronounced, rigid gas permeable (RGP) contact lenses are often used to correct the vision blur. This is because the tear film trapped under the lens neutralises the cone shape and the perfect round shape of the rigid contact lens provides a clear image for the retina once more.
These days, there are lots more options to correct keratoconus than just RGP lenses: we also fit mini-scleral (large diameter rigid lenses) and hybrid lenses (lenses with a rigid centre and a soft lens skirt). Having multiple options means that even those people who have tried unsuccessfully to wear RGPs in the past now have new options to correct their vision.
Monitoring keratoconus progression requires specialised equipment that not all optometrists have in practice. For routine monitoring, measuring the corneal thinning (pachymetry) and mapping the conical shape (topography) is required at least every 6 months to make sure the condition is not progressing. These measurements are also required to accurately fit rigid contact lenses, necessary to achieve good vision in many cases. Keratoconus RGP fitting is a complicated, highly-customised endeavour where we have significant experience.
If you have keratoconus and wish to talk to us about whether you require contact lenses and which contact lens type might suit you best, please don’t hesitate to contact us for an appointment or trial.