Types and characteristics of contact lenses
The biggest function of contact lenses is to correct vision. However, in the process of development, a special process has been developed to print colors on them to modify and enlarge the eyes. The types of contact lenses can be divided into different categories. Today, let's take a look at the types and characteristics of contact lenses.
According to the material, contact lenses can be divided into hydrogel, silicone hydrogel and so on. The advantage of hydrogel is that the lens is soft and easily accepted by the eye, but its oxygen permeability is limited by water. The advantage of silicone hydrogel is that it has strong oxygen permeability, but it is easy to absorb sediment, so it is mostly used to make short-period lenses.
According to the diameter, contact lenses can be divided into large, medium and small diameters. When choosing the diameter, the height of the palpebral fissure needs to be considered. Generally, 14.0mm and 14.2mm are more suitable for most people to wear. If you are looking for more obvious magnification, you can also try 14.5mm contact lenses.
According to the cycle of use, contact lenses can be divided into long-cycle and short-cycle types. Long-term cycles include annual, semi-annual, etc., while short-term cycles include daily, monthly, and biweekly sales. Except for daily disposables, which are single-use products, the rest of the lenses are calculated according to the time of use rather than the number of times of wearing.
According to the water content, contact lenses can be divided into low, medium and high water content. Among them, 30%-50% is low water content, 51%-60% is medium water content, and more than 61% is high water content. The water content has a lot to do with wearing comfort and oxygen permeability of the lens. However, if the water content is too high, it will cause the lens to evaporate faster, and then absorb the tears to replenish the missing water. Therefore, people with low tear secretion need special attention.
However, no matter which standard is used to distinguish, different types of contact lenses have their own advantages and disadvantages, and it is necessary to choose the most suitable one according to the actual needs of the wearer.