Myopia is an eye condition that make objects far away blurry and objects up-close clear. This is because the eye is too long for its focusing power, resulting in the image of a distant object being focused in front of the retina, rather than on it. Myopia are also commonly called nearsightedness or shortsightedness.
Both glasses and contacts correct myopia by refocusing this out-of-focus image back onto the surface of the retina, so the image becomes clear...but only for the central part of the eye. While the central part of vision is in clear focus, the peripheral vision is out of focus, with the peripheral image being focused behind the surface of the retina. The technical term for this phenomenon is called "peripheral hyperopic defocus". Research has found that this image blur in the peripheral retina is part of what drives the progression of myopia in children.
When the eye senses the blurred peripheral image focused behind the retina, it tries to grow to "catch-up" to this image — this becomes stimulus for abnormal eye growth in myopia. The greater the myopia, due to an increase in eye elongation, or a more oblong shaped eye, the greater the mismatch between central focus and peripheral focus, and thus the greater the stimulus for the eye to continue growing longer. Hence, the cat-and-mouse analogy.
This is why regular glasses only correct for myopia and does not help slow myopia progression; in fact, the optics of glasses may accelerate progression by inducing further peripheral hyperopic defocus.
By reducing the peripheral image hyperopic defocus we reduce or eliminate the signals for the eye to grow longer. The more sophisticated technology available in today's spectacle lenses and contacts provide better focusing of light across the back of the eye and ultimately slows the progression of myopia. By slowing down the progression, we keep children's prescriptions low until they achieve stable vision.
LET'S STOP THE CAT-AND-MOUSE GAME! Learn more about myopia control and all the options available for your child.