How to see the parameters of contact lenses?
The parameters of contact lenses are important criteria for judging the quality of lenses. For the safety and health of wearing, it is very necessary to understand the meaning of various parameters before buying contact lenses.
1. Moisture content. The raw materials of contact lenses are high hydrophilic polymer materials. The higher the water content of the lenses, the stronger the oxygen transport capacity, and the more hydrated and comfortable the lenses are to wear. However, when the water content exceeds 50%, the lens is more likely to be damaged and adhered to protein deposits, and the water is more likely to evaporate, which may in turn absorb tears to replenish water, so the wearer will feel more dry eyes.
2. Base Arc (BC). The base arc of a contact lens refers to the central arc of the inner surface of the lens. The larger the base arc, the flatter the lens, and the smaller the base arc, the more curved the lens. When the base arc of the lens is smaller than the base arc of the eyeball, the wearer will feel that the eyeball is oppressed and uncomfortable, and when the base arc of the lens is larger than the base arc of the eyeball, problems such as slippage will occur when wearing. Therefore, it is best not to exceed 0.2MM when selecting the base arc time difference.
That's what you must know about the parameters when wearing contact lenses.
3. Diameter. The straight-line distance between the corresponding points on the edge of the lens is the diameter of the contact lens, and the diameter of contact lenses sold on the market is mostly in the range of 14.0-14.5. If your eyes are small, you may not be able to wear large diameter contact lenses or feel grinding. In the case of colored contact lenses, people will also pay attention to the diameter of the tint because it determines the magnification effect.
4. Oxygen permeability coefficient (DK). The oxygen permeability is related to the water content and material of the lens. The larger the value of DK, the better the oxygen permeability. High oxygen permeability is the key to maintaining corneal respiration and eye health. When purchasing contact lenses, you should choose lenses with high oxygen permeability as much as possible.
The above is the little knowledge about parameters that everyone must know when wearing contact lenses.