Myopia Correction While You Sleep

Correcting myopia (shortsightedness) without surgery has been a dream for many years.

In 1962 George Jesson, an American optometrist, developed a technique to correct this condition by fitting a series of rigid contact lenses to reshape the cornea (the clear membrane in front of the pupil). Today this procedure is known as Orthokeratology. The problem was that the lenses, which needed to be altered numerous times over a period of approximately one year, were often uncomfortable to wear and only achieved limited correction, which meant that the technique lost popularity.

Advanced materials which now enable overnight wear of rigid contact lenses have opened new possibilities. Another important factor is the development of sophisticated corneal mapping instruments which accurately establish the corneal shape and high precision computer-controlled lathes which are used to generate complex lens designs. As a result new lens designs have been developed to reshape the cornea, significantly increasing the speed and effectiveness of myopia correction. With these designs it is not uncommon to correct approximately 70% of shortsightedness after a single night’s wear, with total correction usually achievable within a month.

Suitable patients simply wear the retainer lenses while sleeping at night and are independent of spectacles or contact lenses during waking hours.

While this technique is currently only effective for low to moderate degrees of myopia, the results to date have been spectacular. However, suitability can only be established after a comprehensive examination by an optometrist trained in this technique, accurate profiling of the cornea and establishing the response to specially designed Orthokeratology lenses.

Orthokeratology has been shown to be safe and effective provided that the lenses are prescribed and fitted by a suitably qualified optometrist. It is also essential that patients adhere to the wearing schedule guidelines and the contact lens care and maintenance procedures.

Contact Lens Materials

There are two main types of contact lenses, soft and rigid gas permeable (RGP). Both have advantages and limitations.

Soft lenses, which are more widely used because of their almost immediate comfort and extensive promotion by soft lens manufacturers, are available in several options. They were originally worn for approximately two years before replacement. However, a limitation of soft lens materials is that they accumulate protein and other irritating substances, which can lead to discomfort and reduced wearing time. Attempts to remove these substances have largely been ineffective. Frequent replacement of soft lenses on a monthly, weekly or daily basis is now feasible and cost effective, eliminating this problem.

While the initial adaption period for rigid gas permeable (RGP) contact lenses is longer, there are some definite advantages with an effective lens life of between two and five years. In addition, astigmatism (a common focusing error) is more easily corrected with this type of lens. Dehydration can present problems with soft lenses, especially in airconditioned environments, but is less of a problem with RGP lenses. This type of lens cannot be used by everyone, but patients who are suitable candidates are often the most successful contact lens wearers, rarely reverting their spectacles.