What is Orthokeratology?

Orthokeratology is the use of contact lenses to remould the shape of the cornea to reduce or correct myopic (short-sighted) or 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.

The cornea is highly elastic however, and always returns to its original shape. For this reason retainer lenses are worn typically either two to four nights per week or part of each waking day, eg. 2-3 hours on waking or bedtime each day, after the ideal corneal shape has been achieved.

Why have Orthokeratology done?

The main purpose of Ortho-K is to be free of both contact lenses and spectacles for the majority of or possibly all waking hours. Whilst this is ideal for sports people or those who work in dusty or dirty environments, the freedom from any artificial aid appeals to other myopic or astigmatic spectacle and contact lens wearers.

Is everyone suitable for Orthokeratology?

No. The procedure is only suitable for short-sighted errors up to 4.00 dioptres and up to 3.00 dioptres of astigmatism. 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. Also whilst the success rate is very high, success cannot be guaranteed due to factors outside our control.

What does the procedure involve?

First, an initial assessment appointment. This gives us a chance to both assess the general condition and health of the eyes and also to discuss the likely effectivity of the procedure in your own case.

A series of Ortho-K contact lenses made from high oxygen permeable rigid materials are then fitted in progressive stages to gently reshape the cornea towards less curvature and a more spherical shape. This reduces near sightedness (myopia) and astigmatism whilst dramatically improving unaided eyesight. Excellent vision and comfort are normally maintained whilst wearing Ortho-K lenses.

Most of the visual changes occur rapidly in the first few days and weeks requiring frequent examinations and progressive lens changes. 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.

After treatment and maximum results are achieved, retainer lenses are worn to stabilise the new corneal shape. A period of full time retainer wear is followed by a reduction of daytime wear. Retainers may be worn during the day or night.

Fees

The procedure is both time consuming and involves several and often many lens changes. The cost is approximately $1000. Once complete, the ongoing costs are no greater and often less than conventional contact lens wear.

What are the disadvantages of Orthokeratology?

1. You must be prepared to allow for 4-10 visits over 3-6 months.
2. Retainer lens wear is essential or the cornea will revert to its original shape.
3. The degree of success is high but cannot be always guaranteed.
4. The rate of improvement varies from one person to the next.
5. You must be prepared to follow instructions implicitly for the best results.

Does Ortho-K have any advantages over Excimer Laser surgery?

Yes. Ortho-K is a quarter of the cost; does not involve post-operative pain; does not leave the hazy vision often experienced by patients following laser surgery; there is no loss of Bowmans 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); and above all, the procedure is REVERSIBLE (excimer is not!).