Orthokeratology or Ortho-K is the use of custom designed contact lenses to temporarily reshape the cornea overnight. 

Terminology

- the treatment is called by many names:

• CRT (Corneal Reshaping Therapy)

• Overnight Vision Correction

• Corneal Moulding

-the lenses are more accurately termed moulds or retainers. 

 Who is suitable?

We are initially offering it to patients who fall within these categories:-

1. Have a prescription of -1.00-to -5.50 Sphere and Cylinder 0.75

2. Have dry eyes

3. Enjoy exercise & outdoor sport

4. Those whose work environment is not suitable for contact lenses

5. People tired of wearing glasses or contact lenses during the day

6. Foggy glasses with masks

or, if you simply want to wake up and see clearly.

The process, how and why it works

The cornea can be equated to the first lens of a camera system that helps in focusing incoming light onto the retina.  It contributes between 65-75 % of the eye's total focusing power. Orthokeratology works by reshaping this surface.

The lenses and the moulding are so precise that they alter only the superficial layer of the cornea.

Let’s put some perspective on this. 

The total corneal thickness is 545 microns.  The layer that Ortho-K changes (the epithelium) is 50 microns thick.  Out of those 50 microns hydraulic forces alter the superficial 10-12 microns during the re-shaping process.  The corneal epithelium sheds and is replaced every 7-10 days so all changes are temporary.

How are the lenses designed?

We use an instrument called a Corneal Topographer which uses reflected light to map and measure the corneas carefully and precisely.  This allows the design of individual custom-made moulds. 

The moulds use hydraulic forces to flatten the centre of the cornea thereby changing how light is bent as it enters the eye.

The moulds are rigid gas-permeable lenses made with a high DK material (for greater oxygen permeability). This makes them safe to wear under a closed lid while sleeping.  When the lenses are removed in the morning, the cornea stays altered for a day (sometimes two) and vision is corrected without the need for glasses.

If you stop wearing the lenses at night, your eyes will revert to their original shape and the refractive error will return. Ortho-K is a temporary change.  You must keep wearing the lenses regularly to have vision correction.

 The process

Ortho-K fitting is a highly specialised process and requires several visits.

• Initial consult and suitability

• Fitting

• Visits on Day-1, Week-1, 1 month, 3 months, 6 months, 1-year (review appointments)

We will teach and instruct you on how to insert & remove the lenses as well as how to clean and disinfect them on the day of collection.  This is normally a one-hour appointment.  We then give you your lenses to go home with and book an appointment for the following morning to assess the fit and vision.  Within the first week of wearing the lenses every night, most people achieve 80% of correction.  For some people it can take two weeks.  It is possible you may need a few adjustments to get to the final lenses. Once you get there, you’ll use the same lenses each night to maintain the correction. In this initial period results are very much dependent on patient compliance in wearing the lenses nightly.