The discussion of the background of the invention herein is included to explain the context of the invention. This is not to be taken as an admission that any of the material referred to was published, known or part of the common general knowledge at the priority date of any of the claims.
It has been observed that some individuals, in particular children, focus inaccurately when they observe an object which is situated at a short distance away, that is to say, in near vision conditions. Because of this focusing defect on the part of a myopic child which is corrected for his far vision, the image of an object close by is also formed behind his retina, even in the foveal area.
Many type of products for slowing down myopia progression can be used, such as ophthalmic lenses, contact lenses or drugs.
For example, to avoid a myopia progression which is due to such focusing defect, it is known to use a myopia-correcting lens which is of the progressive multifocal ophthalmic lens type. An example of such progressive multifocal ophthalmic lens is disclosed in U.S. Pat. No. 6,343,861.
Bifocal lenses may also be an example of ophthalmic lenses that can be used to slow down myopia progression.
Each individual may react differently to the different myopia control products. However, since myopia progression is a long term process it is difficult for an eye care professional to estimate the efficiency of a given myopia control product for a wearer.