SO HOW DOES IT WORK?
In order for an eye to see clearly light must enter the pupil and be focused on the retina. If an eye is myopic (short sighted) then the light focuses too quickly so by the time it reaches the retinal surface it is blurred. In order to alter where the light is focused spectacle or contact lenses can be prescribed. This is how we routinely improve our vision but this will not slow the increase in myopia (short sightedness) in a child’s eye.
The very central area of our retina is known as the macula and this area of the eye is responsible for the critical portion of our vision. If we are too see clearly the light must be focused on the macula perfectly. The human eye is also stimulated by light as we move away from the macula, towards the periphery of the retina. It seems that if the macula is corrected perfectly but the peripheral areas of the retina are not corrected fully then the eye’s tendency to grow longer is reduced. So what is needed is a lens that can give perfect focusing in the centre but reduced focusing around the edge.
Dual Zone or Multi Focal contact lenses do exactly that. They have two area of focus, a central one which can provide clear focusing to the macula region and a peripheral one which can have a different optical power so the constant growth to a child’s eye can be reduced.