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The appeal of being able to see without glasses is a powerful one. As a result people have found many ways to approximate this. The more drastic solution is of course laser surgery where part of the cornea is burned off. Of course this process is not reversible since you can’t put back the tissue you have removed. There are also other potentially serious side effects that can occur with laser surgery. So optometrists have found an alternative approach – a technique which can be reversed.

Ever since contact lenses became available in the 1950’s, optometrists theorized that it may be possible to mould the shape of the cornea. Optometrist Newton Wesley coined the term “Orthokeratology.” In the early days this required multiple modifications over a period of months and the result tended to be unpredictable.

It took another 20 years before manufacturing technology was able to make computer guided gas permeable reverse geometry lenses. This was pioneered by Richard Wlodyga, OD. Originally the lenses were prescribed for day wear only. However, from 1993 onwards wearing the lenses at night started to become popular.

The Jessen formula (after George Jessen which designed the first OK-Lenses in the early 1960’s), upon which most OK-lens designs are based, assumes that there is a linear relationship between myopia reduction and base curve selection. In other words, if the cornea has a flat K reading of 42.00 Diopters and a Rx of – 2.00 D, you would fit a 40.00 D base curve which would change the corneal curvature and therefore the refraction by the required amount.

Orthokeratology (OK) lenses are a mechanical process that seeks to mould the cornea into a flatter shape and therefore alter the focusing ability of the eye. Special custom made hard lenses are worn at night for this purpose.

Potential problems

The initial fitting has to be done by specially trained optometrists, because incorrect fitting can cause problems such as centration, when the lense is not fitted propperly bubbles can form under the lens if it is not fitted well.

A common problem is that the lenses stick to the cornea and must be released upon waking either by applying eye-drops or by squeezing the eyeball so that the lens pops out. This procedure often leads to infections, because there is a tendency to inadvertently touch the eye. In some cases corneal ulcers may appear on the cornea. In the relevant literature, reports of infection are not very high. However, infections are a common problem especially if children have to manage the lenses themselves. Chronic lens binding can also cause severe corneal staining. In addition the exposure to preservatives found in the contact lens solution is increased since the eyes are closed while the lenses are worn. Because of the binding issue, when the lens stick to the eye, the FDA has only approved a few types of OK-lenses for general use.

How effective are OK-lenses?

Research shows that a maximum of -4.00 Diopter change is achievable with OK-lenses. So this procedure is only for mild myopia. Also it is not a permanent solution. Like wearing glasses, when you stop using them the vision goes back to what it was before.

Compared to laser surgery, this is a much safer procedure, since nothing is being cut. It is similiar to wearing a corset. While you wear it you look slim. However, when you take it off, your shape changes back to what is was before.

Compared to natural Vision Training it does not seem worth the effort and expense. Also, Vision Training offers a more permanent result and it is a lot cheaper. The only drawback with Vision training is that you have to do the exercises often enough to get significant results.

Vision training is permanent – OK lenses are temporary, cumbersome, costly and may potentially cause serious complications.ions.

 

<Case story here>

If your child already wears OK lenses, he/she should stop using them a few days before attending the Magic Eyes class. The eyes will start reverting back after 48 hours and after a week the eyes will essentially be back to normal.

Your child may experience great changes in vision. Especially, if the lenses were expected to correct more than – 2.00 D to – 4.00 D. This can sometimes cause a crisis of confidence. One day he/she appears to be making great progress but the next day it seems like back to square one.. It is therefore important to be aware of that and focus more on the effort the child has made. It is also best to start this project at the beginning of a long holiday period, so that the child has plenty of time to adapt.