Orthokeratology may be defined as ‘temporary neutralising the eye’s power by the programmed application of rigid contact lenses’. On taking the lenses out, the eye retains its ‘neutral’ power allowing clear vision for an extended period of up to two or three days depending on the individual.
Orthokeratology has been around for over thirty years. It is totally reversible and a safe process that offers an alternative to other forms of vision correction. Stop wearing the lenses and your prescription returns to normal in around five days.
It was found that the neutralising process occurred much faster when the lenses were slept in. This resulted in the labels ‘accelerated orthokeratology’ or ‘overnight vision correction’ (OVC) and you will also find the term ‘ortho k’. All these refer to the same process.
Wearers find overnight orthokeratology more comfortable and altogether more satisfactory than conventional lenses. Many chose this because of dry eye or other comfort related issues present with their existing lenses which do to exist in orthokeratology.
It is a minimally invasive, reversible technique appealling to patients unsure of or unsuitable for refractive surgery or too young to be considered for surgery.
Additionally, they appeal to active or professional sportspeople since participation without wearing lenses means there are no issues of lens loss. They are of particular benefit to swimmers and martial arts participants. In the latter case, normal contact lens wearers have had contests stopped because of conventional lens lose during bouts – something that doesn’t happen when lenses are only worn at night.
It is generally considered that orthokeratology is only available for low to moderate short sight with low degrees of astigmatism. While this has been the main area of correction, the last decade has seen the range of correctable prescriptions expanded. Now they can be used for long sight or reading glasses correction (the writer falls into this category – the joy of not having to search for my reading glasses!). Much higher amounts of astigmatism are also being successfully corrected. This has the greater advantage of providing more stable vision than conventional lenses.
Despite its popularity, laser surgery does not always give permanent stability of vision. Where short sight has started to develop again, satisfactory stabilisation can be provided by orthokeratology where there is no desire for repeat laser surgery.
Possibly the greatest benefit of orthokeratology will be found in its now substantiated ability to stabilise short sight. While not being able to reverse it, the ability to stop a young person at a prescription of -1, -2 or -3 where the prescription is seen to be rapidly changing, is a huge potential benefit given the sight problems that higher levels of short sight bring.
For the more mundane, not wanting to wear contact lenses full time but not wanting to be known as ‘the lady with glasses’ has also been cited as a reason for trying orthokeratology.