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Orthokeratology (OK) involves wearing specially designed rigid gas permeable lenses overnight to reshape the cornea – much like retainers for the teeth. The reverse geometry design of the lens redirects tear film forces around the eye allowing for steepening of the mid-peripheral cornea and flattening of the central cornea. These changes are non invasive, reversible and allows for the correction of low to moderate degree of myopia (short sightedness) and astigmatism.

Orthok Diagram

Recent studies show that OK lenses slow the progression of myopia in children much more effectively than bifocal spectacles or multi-focal soft contact lenses. They do this by slowing down axial elongation – the process of eye stretching in the back of the eye. Current research suggests that axial elongation occurs because light focuses behind the peripheral retina and that steepening of the mid-peripheral cornea created by OK lenses counteracts this.

Is Orthokeratology for you?
change in topography after OK

Although OK lenses have some clear benefits – not everyone is suited for them. Cleaning and hygiene is critical to the safety of overnight wear contact lenses so we will only give this form of treatment to responsible patients.

An initial consultation, which spans over two to three consultations will determine whether your refractive prescription can be corrected effectively. If you are suitable, an appropriate OK lens is selected, insertion and removal and cleaning will be taught so you are ready for your first night wearing these lenses!

After the first night, we”ll know whether these lenses are right for you!

The corneal topography on the right shows the changes to the cornea with OK lens wear.


For more information about the topic of orthokeratology. Mivision has a very comprehensive article on ‘Myopia Control in Children through Contact Lenses’