The Advantages of Contact Lenses

Daily lenses are put on in the morning and removed at night. These contact lenses are not visible during the day. In these lenses you will feel comfortable. Toric contact lenses used to correct myopia and hyperopia in the presence of astigmatism. Spherical lenses are used to correct myopia and hyperopia. Multifocal contact ones are used to correct presbyopia. To improve the quality of all types of lenses an aspheric design can be used. For the manufacture of contact lenses different materials are taken. Most of the hydro gel is a polymer. Daily lenses are made from such polymers. Contact lens material largely determines its properties. The major characteristics of the material include water content and oxygen permeability. An important requirement for discount daily lenses is its resistance to the ability of passing oxygen and containing a sufficient amount of moisture. For hydro gel contact lenses, the more water content, the more they allow to enter oxygen to the cornea, which positively affects the health of the eye. However, with increasing water content hydro gel lenses have become too soft and difficult to handle. Therefore, the maximum water content of hydro gel lenses does not exceed 70%. The ability of contact lens oxygen is characterized by a special pass coefficient Dk / t (Dk - oxygen permeability of the lens material, and t-thickness of the lens in the center). For hydro gel lenses Dk / t is usually in the range of 20-30 units. That's enough for daily wear. The main optical parameters of contact lenses: the power of the sphere, cylinder power (in diopters) and the position of the cylinder axis (in degrees). The last two parameters are specified for toric contact lenses used to correct astigmatism. With proper selection of the consulting, compliance with all the recommendations on terms of carrying, handling and processing, daily contact lenses are not capable of causing harm to eyesight. When it is non-compliance with the rules of hygiene, improper handling of lenses - probably infected conjunctiva. Failure to comply with the terms of wearing, regular prolongation of planned replacement lenses, the use of lenses with low oxygen permeability are perhaps a gradual sprouting of vessels in the cornea and other complications that are unfortunately often irreversible.

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