The importance of water content in contact lenses
For contact lenses, water content is a very important parameter, representing the proportion of water in the lens.The contact lens that water content is high wears in the eye can be very comfortable, and water content is low makes a big difference, so this is easy to think water content is high contact lens is better, but is this really the cause?
From the perspective of oxygen permeability, high water content does have certain advantages.Oxygen in the atmosphere usually needs to be dissolved in water before it can be transferred to the cornea through the lens. In this process, water is the carrier of oxygen transmission, so high water content has less barrier to oxygen.Although silicon hydrogel contact lenses with the addition of silicon to achieve a double increase in oxygen permeability and water content, so that oxygen permeability is no longer limited by water content, but as the mainstream of the market, hydrogel still need to find a balance between oxygen permeability and comfort.
From the point of view of wear, low water content is relatively better. Although the high moisture content can bring a temporary moisture softness and better comfort performance, but these moisture will quickly evaporate, in this case, the lens to maintain water content, will absorb a lot of tears to replace the lost moisture, the end result is that the lens looks very watery, but the eyes are very dry.This is the fatal weakness, high water cut lenses also let tear secretion of less people stop there.
The water content has always been very controversial, which leads to many people do not know how to choose. In fact, contact lenses focus on fit, who can not absolutely say which one is better or not.If the eye can adapt, choose a lens with high water content for optimal comfort, but try to choose a lens with low water content is better if the eye is dry.