How to choose the center thickness of contact lenses?
The biggest advantage of contact lenses is light and convenient, but in fact the thickness of the lens is not uniform, but the middle is thick and the edge is thin. Usually we say that the thickness of contact lenses refers to the center thickness, the center thickness of less than 0.04mm is called ultra-thin type, the center thickness of 0.04mm-0.09mm range is standard type, and more than 0.09mm is called thick type. The thickness of contact lenses is determined by the lens material, degree and other parameters, which has an impact on the molding degree, durability, oxygen permeability and other aspects of the lens.
The thinner the contact lens, the better the oxygen permeability, and the more comfortable to wear, but the water retention of the lens will be relatively poor, it is easy to dehydrate and dry, and it is also more prone to damage when wearing and caring, and it is not very good to operate. Thick lenses are not easy to dehydrate, durability is better, usually as a long cycle type, its disadvantage is limited oxygen permeability, easy to cause corneal hypoxia, may also produce a certain foreign body sensation.
Therefore, it is generally recommended that people who are easy to dry eyes and try contact lenses for the first time choose slightly thicker contact lenses, because of low water content and good water retention, so it will not aggravate the symptoms of dry eyes during wearing. If it is a relatively high degree or more the pursuit of comfortable oxygen penetration people to buy, author recommends choosing thin lenses, taking into account health and safety.
For color contact lenses, due to the structural design of the sandwich process, the dye layer needs to be sealed in the middle of the lens, so it is not possible to make ultra-thin lenses, only the thickness of the standard type. There are many brands and series of contact lenses, and it is actually difficult to choose the right contact lenses, so we should know more about the relevant knowledge before wearing them!