WHAT IS ORTHO K?
Orthokeratology, also known as ortho K or OK is a nonsurgical procedure using custom made contact lenses to gently reshape the curvature of the eye while you are sleeping. This allows you to have clear vision without glasses or contact lenses during waking hours.
Ortho K is an effective treatment for correction of certain ranges of short sightedness (myopia), long sightedness (hyperopia) and presbyopia (blurred near vision). It is an excellent alternative to LASIK if you are not ready for surgery. The process is also entirely reversible.
WHAT TO EXPECT WHEN YOU BEGIN ORTHO-K
At your initial Ortho K appointment, your orthokeratologist will check your prescription, ensure your eyes are healthy and perform corneal topography (map of the front surface of your eye). Corneal topography is like an elevation map that demonstrates the exact shape and curvature of the cornea. This is the information that is used to custom make your ortho K retainer contact lens.
Once the lenses are made to order, you will be booked into an appointment to collect your ortho K lenses. You will be taught how to insert, remove and care for your new lenses. Your Orthokeratologist will then inform you of the timing of subsequent visits to ensure success with the treatment. Your retainer lens may need to be modified along the way to ensure your vision is good and your lenses are healthy for the eyes.
HOW FAST DOES ORTHO K WORK?
Ortho K can provide good vision in a surprisingly short amount of time. However, this may vary depending on a number of factors, such as the curvature of your cornea and the degree of your prescription. Your orthokeratologist will discuss with you.
ORTHO K AND MYOPIA CONTROL
The prevalence of short sightedness or myopia is increasing significantly worldwide. China, Taiwan and Singapore have rates of myopia in young adults of 7080 per cent. In the United States, the prevalence has also increased from 25 to 42 per cent among 12 to 54 year olds. An Australian study found that 31 per cent of 17 year olds are now myopic. (p. 491 Clinical and Experimental Optometry)
Rapidly increasing myopia is problematic as high myopia (5.00D or more) significantly increases the chance of sightthreatening eye conditions, such as myopic macular degeneration and retinal detachments. High myopia is now recognised as a major contributor to blindness around the globe.
Myopia occurs when light entering the eye is focused in front of the retina i.e. the eyeball is too long. Glasses and standard contact lenses correct this by refocusing the light directly onto the retina. There is increasing evidence that one of the causes of progression of myopia is peripheral retinal blur. This theory states that although glasses and standard contact lenses correct your central vision, they do not focus the peripheral vision as well. This encourages the eyeball to grow longer, which in turn causes the progression of myopia.
Research surrounding ortho K and myopia control has produced encouraging results. Ortho K reduces the amount of peripheral defocus associated with glasses and normal contact lenses. Ortho K has been shown to reduce the elongation of the eyeball by 3050 per cent (p. 492).
WHAT ELSE CAN I DO TO REDUCE MYOPIC PROGRESSION?
A number of studies have also shown that increased time outdoors is also important in reducing the incidence of myopia and rate of myopic progression. One study has shown that incident myopia was reduced by 23 per cent over a three year period with 45 minutes of structured outdoor activity each day (p. 495). However, the direct cause of this remains unclear. Possible explanations include increased exposure to short wavelength (blue) light, increased vitamin D levels, increased focus on objects that are further away and reduced near work.
“Visual hygiene” is also important when focusing at close distances for long periods of time. During extended periods of reading, computer work or gaming, a 20 second break every 20 minutes is recommended. During this break focus on an object at least 20 feet i.e. 6m away (20-20 -20 rule). This helps reduce the strain on the eyes during near focus. In addition, make sure you are not reading or using a screen in the dark. The ambient lighting should match the brightness of your screen.