What is myopia?
Many people suffer from varying degrees of myopia, or short-sight, and
sometimes also have astigmatism. Myopia is generally a result of the eyeball
being fractionally too long to allow light rays to be focussed correctly
at the back of the eye, whilst astigmatism is an optical defect created
when the shape of the cornea is not perfectly round. The cornea is the
major optical surface of the eye and any small distortion of its shape
will blur the image on the retina at the back of the eye.
A soft contact lens can bring the retinal image back into focus by creating
an artificial surface of a different curvature to the cornea. To correct
short sightedness the surface of the contact lens must be flatter than
that of the cornea which it is sitting on. If astigmatism is also present,
the soft contact lens needs to be of a more complex curve.
Surgical correction of myopia
Myopia may be corrected by a variety of surgical techniques. For mild
degrees of myopia or myopic astigmatism, LASIK
surgery is often the best approach. Alternatively a variety of intra-ocular
procedures can be used such as insertion of an implantable
contact lens (ICL), or an Artisan, Artiflex, or Cachet lens. Sometimes the natural lens of the eye is removed by clear
lens extraction with implantation of an intra-ocular lens implant.
The various lens implantation procedures may also be accompanied my LASIK
treatment, the combination surgery being referred to as Bioptics.