Myopic control is to slow down the progression of short-sightedness in children may help in preventing myopic degeneration of their eyes. It is well-known that highly myopic patients are at high risk of developing many of the eye diseases e.g. glaucoma, retinal degeneration, retinal detachment, cataract, choroidal neovascularization (CNV), macular degeneration and more. All these are sight-threatening.
Ordinary Myopic Eyeglasses
For myopia(short-sightedness), to correct vision, we have to use minus prescription lens to re-locate the central focus back onto the retina.
Unfortunately, traditional ophthalmic lenses are built according to the prototype of the camera lenses which generate a flat focal plan. The peripheral image will he focused behind the retina while the central focus located precisely on the central retina. Accordingly, the peripheral retina will elongate to catch-up the position of the peripheral image. That will generate the tendency for myopia increase.
In order to control the myopia progression, optometrists and researchers worldwide spent a lot of effort to develop effective ways to help the myopic children. There are three “defocus” prototypes available nowadays, such as Orthokeratology, Defocus incorporated soft contact lens and Peripheral defocus eyeglasses. Our optometrist may choose the method best suits the life style of the children or teenagers accordingly.
Ways of Myopia control
Orthokeratology 88% > Myopia Control Lens for children 59% > Defocus incorporated soft contact lens 50%
1. Orthokeratology (Night wearing contact lenses)
Orthokeratology is the use of specially designed gas permeable contact lenses that are worn during sleep at night to temporarily correct short-sightedness and other vision problems so glasses and contact lenses aren’t needed during waking hours.
“Ortho-k” lenses is used to control myopia progression in children. Evidence suggests short-sighted kids who undergo several years of orthokeratology may end up with less myopia as adults, compared with children who wear eyeglasses or regular contact lenses during the peak years for myopia progression. Many eye care practitioners refer to these lenses as “corneal reshaping lenses” or “corneal refractive therapy (CRT)” lenses rather than ortho-k lenses, though the lens designs may be similar.
2. Defocus Incorporated Soft Contact Lens
Defocus Incorporated Soft Contact Lens is a new option for myopia control other than Orthokeratology. They are different from other ordinary soft contact lenses, an additional set of refractive power to control the short-sightedness progression is added to the lens. The additional power will generate an additional focal plan in front of the retina and naturalizing the tendency for the eyeball elongation.
3. Myopia Control Lens for children
Myopia control lens also have been tested for myopia control in children, but results have been less impressive than those produced with myopia control contact lenses.
But in March 2014, researchers in Australia and China published the results of a three-year clinical trial that evaluated the progression of short-sightedness among 128 myopic children ages 8 to 13 years all participants had experienced at least -0.50D of myopia progression the year progression the year preceding the start of the study.
One group of children wore conventional single vision eyeglasses, a second group wore myopia control lenses, and third group wore myopia control lenses with prism. After three years, children who wore either type of myopia control lenses eyeglasses had a significantly less mean progression of short-sightedness (-1.01D to -1.25D) than children who wore single vision lenses(-2.06D).
Research also shown that while spending time outdoors, especially in the sun, there is a positive effect on eyesight. Parents are also advised to limit the time children spend in front of computers or on digital devices like mobile phones and tablets as overuse can cause eyestrain.
