For children who are not suitable for contact lens myopia management or whom do not want to wear contact lenses, there are myopia control spectacle lenses that are designed to help to slow down the progression of myopia!
Worldwide, there are two theories as to what causes myopia to progress. One of the theory is the hyperopic defocus when the eye is corrected with single vision spectacle lens. The other approach is the accommodative lag theory. Theses spectacle lenses are designed based on these theories to help to slow down the progression of myopia in children.
Myovision Pro lenses are a type of spectacle lens design by Zeiss. This lens applies the principles of Peripheral Defocus Management: the correction of the peripheral “hyperopic shift” in the myopic eye. This correction will allow the myopic eye to reduce the progression of eye elongation, thereby resulting in the reduction of myopia progression.
MyoKids lenses apply the theory of Accommodative Lag Management: providing optimum control of the accommodative lag during near vision tasks, while maintaining a clear and comfortable vision at all distances. Reducing the amount of accommodative lag is known to help in the potential reduction of myopia progression. The design of MyoKids lenses may sound similar to progressive addition lenses used in the Presbyopic condition. However, it is not an ordinary progressive lens. MyoKids lenses are new and innovative progressive addition lenses specially designed for children’s need.
When a person conducts near task (e.g. reading a book), the eye internal muscle should response and make changes to the crystalline lens in the eye to focus accurately on the reading material (Like a camera focusing clearly on the target). However, this accuracy may not always happen. Most of the time, our focus are not on the object but slightly behind the plane of the object. This error in focusing is known as accommodative lag. Studies have shown that people with short-sightedness tend to have a higher amount of focusing error at near as compared to people who are not short-sighted.
When accommodative lag occurs, it creates a hyperopic defocus when a person is focusing on a near target. This cause the best image of the near object to be located slightly behind the retina. If this hyperopic defocus is prolonged and sustained during prolong near work, it is suggested that it can contribute to the progression of myopia and axial elongation.
It has been found in studies that by using a near addition power over the distance prescription, it can improve the focusing of the eye and thereby reducing the amount of accommodative lag.