How to choose the water content of contact lenses?
Water content is one of the most important parameters of contact lenses, which determines the softness of the lens, so it also directly affects the wearing experience.Generally speaking, less than 40% is called low water content, 40%-60% is called medium water content, and higher than 60% is called high water content.So, when we buy contact lenses, is it better to choose a high water content or a low water content?
People generally have misunderstandings about water content. They also prefer lenses with high water content when they buy. They feel that these lenses are softer, have better oxygen permeability, and are definitely comfortable to wear.In theory, this is true, but in actual use, the lens with high water content is more easily dehydrated and dried. After the water evaporates, it will continue to absorb the tears to maintain the original water content, making the eyes more dry and uncomfortable, and making the lenses more susceptible to aging.Especially in air-conditioned rooms, dry and windy areas should avoid the choice of high water-containing lenses.Although it can be relieved occasionally through the eye lotion, but excessive dependence can affect the normal tear secretion function.
In general, lenses with water content higher than 50% are easily deformed and adsorbed protein precipitates, and the correction effect on astigmatism is not satisfactory, and is often used for making daily disposal.The low-water-containing lens is well formed, which can reduce the precipitation adhesion to a certain extent and has a relatively long service life.The most suitable water content should be between 38% and 40%. At this time, the parameters of the lens are relatively balanced. The yearly disposable lens is basically in this range, so it is suitable for most people and climate.
Choosing an unsuitable contact lens is very harmful to the eyes. If the eyes are very dry, be sure to choose a lens with low water content.