ORTHOKERATOLOGY.
MYOPIA
REDUCTION
AND
CONTROL.
OrthoK, Wear by Night but not by Day!
WHAT IS OrthoK?
The reduction, modification or elimination of
refractive error by the programmed application of contact lenses or other non-invasive
procedures.’
Orthokeratology uses Contact Lenses to remould the Cornea, to reduce or
correct Myopic (short-sighted) and Astigmatic (irregular surface) errors of the eye. In
some ways this is similar to the use of dental braces by an Orthodontist to straighten
crooked teeth. The main difference is that if a tooth position is corrected for some
months it will stay in the new position. However the Cornea is highly elastic,
and always returns to its original shape. For this reason the lenses are worn nightly or
on alternate nights after the ideal Corneal shape has been achieved and removed in
the morning giving perfect vision without the need for spectacles or contact lenses.
WHY HAVE OrthoK DONE?
The main purpose of OrthoK is to be free of both Contact Lenses and
Spectacles all day.
The freedom from any artificial aid appeals to Myopic Spectacle and
Contact Lens wearers.
It is ideal for sportsmen, swimmers or those who work in dusty or dirty
environments.
Some long term contact lens wearers develop a sensitivity to their
lenses which results in reduced wearing time. OrthoK can solve these problems.
Possibly the ideal situation for using OrthoK is for the
teenager just becoming Myopic. Not only does it have all the advantages already given
above, but the procedure appears to stabilise or retard the progression of the Myopia.
For Myopes with higher errors, there is sufficient reduction of
the error to enable improved functional vision when the Lenses are removed.
If you have difficulty in achieving the required visual standard
for employment then OrthoK may help.
IS EVERYONE SUITABLE FOR ORTHOK?
No!
The procedure works best from +3.00D to -6.50D of Myopia
and -1.50D of Astigmatism. Errors above this may
be reduced but total correction is not usually possible.
The procedure also does not work as effectively on very steep or very flat
Corneas. In addition there are several unknown factors for each individual; the complexity
of the Corneal shape and the rigidity of the Cornea itself.
Thus the speed of Corneal moulding from one individual to the next will
vary.
Whilst the success rate is very high, success cannot be guaranteed due to
factors outside my control.
WHAT DOES THE PROCEDURE INVOLVE?
First an initial assessment appointment to include a full
Sight Test and Computerised Corneal Topographical Scan. This gives me a chance to both assess the general
condition and health of your eyes and also to discuss the likely effectivity of the
procedure in your own case.
A pair of trial lenses are then issued for an overnight trial and I will
see you the next morning. After another Sight test and scan the change in your
corneal shape and reduction in prescription is assessed. If the fit is not correct then
another overnight trial may be needed.
Once I have established the correct fit and that I can reduce your myopia
so that you will be able to achieve normal vision, a pair of OrthoK lenses will be
ordered. When these arrive, the fit is assessed and you will be given them to wear
every night for a week. Excellent vision and comfort are normally maintained whilst
wearing OrthoK Lenses.
You will be assessed after a week and if any modifications are needed a
new pair of lenses will be ordered.
This series of OrthoK Contact Lenses, made from High Oxygen Permeable
Rigid Material, gently reshape the Cornea towards less curvature and a more spherical
shape. This reduces Myopia and Astigmatism whilst dramatically improving unaided eyesight.
Most of the visual changes occur rapidly in the first few days and
stabilisation procedures then follow at a slower pace over the next few months. The
program length varies between 3 and 6 months depending upon the degree of visual error.
When the maximum results are achieved, the final pair of lenses are worn
to stabilise the new Corneal shape.
The final wearing time depends on many variables, but I consider the
treatment aim to be good unaided vision all or most waking hours, with Lenses being worn
overnight . Some patients will be able to wear their Lenses every other night.
WHAT ARE THE ADVANTAGES OF ORTHOK?
Good Vision without Spectacles or Contact Lenses for Most of the day.
It is Not a Surgical Procedure
It is Reversible.
It is Non-Invasive.
It is Modifiable.
It Does Not Hurt.
Using well established Contact Lens Fitting Techniques mean that there
are very few risks.
WHAT ARE THE DISADVANTAGES OF ORTHOK?
You must be prepared to allow for 4-10 visits over 3-6 months.
Retainer Lens Wear is essential or the Cornea will revert to its
original shape.
The degree of success is high but cannot always be guaranteed.
The rate of improvement varies from one person to the next.You must be
prepared to follow instructions implicitly for the best results.
DOES ORTHOK HAVE ANY ADVANTAGES OVER EXCIMER LASER SURGERY?
Yes!
It does not involve post-operative pain.
It does not leave the hazy vision often experienced by patients
following laser surgery.
There is no loss of Bowman's membrane (the tough protective layer just
under the Corneal surface).
Both eyes are done together (rather than several weeks or months apart).
Changes in prescription over time can be dealt with (unlike Excimer).
OrthoK is significantly cheaper.
The procedure is time consuming and can involve several Lens changes.
However, once complete, the on-going costs are no greater and often less than
conventional Contact Lens wear.
An enzyme, which temporarily softens the cornea, is under development.
When this is applied after a course of OrthoK, the change in shape will
prolonged! However, this is likely to take a few years to become available.
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