Implantable Contact Lens (ICL) for myopia
|Staar® Implantable Contact Lens (ICL)
Since the range of optical defects correctable by ICL's overlaps with that which can be achieved with Artisan lens implantation, or by LASIK, for some people there may be a choice between the treatments, decided upon by the following factors:
Easily adjusted optical outcome and effective correction of astigmatism.
The quality of the optical correction with LASIK may not so good as that
achieved by an ICL especially in high degrees of myopia or hypermetropia.
This is partly because the final optical surface created may be less regular
than that of a manufactured lens, due to irregularities in the laser treatment
and the wound healing process.
Intraocular lens implantation carries an extremely small but unavoidable
risk of introduction of infection into the eye. This is an extremely serious
complication which can lead not only to loss of vision, but even loss
of the eye.
Intraocular surgery also carries the risk of damage to other structures in the eye, such as the lens, the iris, and the trabecular meshwork, giving potential complications of cataract, glaucoma, iritis, and also possible retinal complications such as cystoid macular oedema, and retinal detachment.
Intraocular surgery causes some irreversible loss of corneal endothelial
cells. Although the cell loss does not seem to be progressive, loss of
these cells diminishes the functional reserve of the cornea, and could
ultimately contribute to corneal failure due to endothelial cell depletion.
In the normal eye the front part (anterior segment) is filled with aqueous fluid which circulates from the ciliary body, through the pupil, to the trabecular meshwork in the angle between the iris and the cornea. When an ICL has been inserted in position between the natural lens and the iris, it can impede the flow of aqueous fluid to some extent. To avoid problems from this, a couple of small openings (iridotomies) are created in the iris to allow some of the aqueous fluid to by-pass its normal route through the pupil. The creation of the iridotomies is done with a YAG laser - an invisible infra-red laser beam which vaporises the iris tissue. This simple and painless procedure is carried out under local anaesthesia typically a week or so before the ICL surgery.
The insertion of the ICL is also generally carried out under local anaesthetic.
Drops are put into the eye to dilate the pupil and anaesthetise the cornea.
A small incision (3mm) is made at the edge of the cornea, and the ICL
is injected into the eye and carefully placed over the natural lens. A
drug solution is then injected into the eye to constrict the pupil. After
the operation antibiotic drops are given to help prevent infection and
steroid drops to suppress inflammation. Visual recovery is rapid, with
functional vision virtually straight away and stabilisation of refraction
within a few weeks.
|Links: A patient's tale|