Read the parameters of contact lenses
For both new and experienced contact lens wearers, it takes a lot of work to understand the many parameters of contact lenses. Today, author leads you to quickly understand the parameters of contact lenses.
The first thing I'll talk about is the materials of contact lenses -- hydrogels and silicone hydrogels. Hydrogels are widely used. Their advantage is that they are moist and soft, but their disadvantage is that oxygen permeability is limited by the water content of the lenses themselves. Silicone hydrogel belongs to the new generation of contact lens material, oxygen permeability is improved, but the lens is slightly hard, relatively long adaptation time.
The next thing to mention is the life cycle of the contact lens. After the lens is unwrapped, the use cycle is equivalent to the shelf life of the lens, overdue should be abandoned. In general, long-period lenses are more affordable, but require prompt care, while short-period lenses are more expensive, with the most expensive being daily casts, but are healthier and safer. When conditions permit, author more recommend that you choose short cycle discard contact lenses.
After that, let's talk about the water content and oxygen permeability of contact lenses. For hydrogel contact lenses, high water content means high oxygen permeability, but silicone hydrogel materials are not subject to this limitation. When selecting the water content, the personal tear secretion should be given priority. People with dry eyes are more suitable to wear contact lenses with low water content, so as to avoid the rapid evaporation of water in the eyes. But in general, the more oxygen-permeable the lenses, the better.
And finally, the contact lens. In order to obtain a more appropriate correction effect, author recommends professional optometry before buying contact lenses. In addition, it is important to note that the degree of contact lens and frame glasses are not completely consistent, we must not forget to convert oh!