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).