Many parents rush to take their children to the hospital to optometry before the school starts, but it is difficult to choose childrens glasses: choose cheap lenses for fear of hurting your eyes, buy expensive lenses for fear of wasting money, how to choose the right lenses? In this regard, Huang Xinhui, a national optometrist from the optometry Center of Shanghai Eye Disease Prevention Center (Shanghai Eye Hospital), gave some suggestions.
Are more expensive lenses better?
Many parents who wear glasses know that the same brand and the same series of lenses, the higher the refractive index, the thinner the lens and the higher the price. If you want the lens to be light and thin, the high refractive index lens is indeed a good choice, of course, the price is more expensive.
Under normal circumstances, the higher the refractive index of the lens, the lower the Abbe number, and the high thinness and high clarity of the lens can not be both. The refractive index of the lens can be selected according to the height of the glasses and the thin and light needs of the lens.
In addition, it is recommended that highly short-sighted people choose a frame with a small mirror circle, because the myopia lens is a concave lens with a thin middle and a thick edge. Select a small mirror ring, processing and cutting relatively more, so it looks beautiful and thin.
Glass or resin lenses?
Glass lenses have many advantages such as high light transmittance, high refractive index, high clarity, wear resistance, etc., but it is relatively heavy, fragile, and there are safety risks, so it is not recommended for children to wear glass lenses.
Resin lenses are lighter than glass lenses, not easy to break, comfortable to wear, has become a mainstream product. However, it is easy to wear and scratch during use, and the ground lens will affect the clarity of the sight, so it is necessary to replace the new lens in time.
Is it okay to replace the frame with an old lens?
Parents often ask: "The original frame is damaged and deformed can not be used, but the old lens is intact, can you change the old lens to the new frame?"
If you must keep the original lens, in order to ensure that the original lens parameters remain unchanged, it is recommended to change the original frame of the same type.
For children with high diopter and diopter, during the secondary processing of the old lens, it is easy to have changes in pupil distance, pupil high error and astigmatism axis, which will make the eyes more prone to fatigue, and even cause other visual problems, affecting the correction of vision, so it is not recommended to try this approach.
Children's diopter is not too stable, easy to change, should be timely according to the results of optometry with new lenses, for children with obvious degree changes is more inappropriate to continue to use the old lenses.
