Hard contact lenses
Modern hard contact lenses have many differences from their predecessors. Their major advantage is in their ability for excellent oxygen transmissibility. That is why hard contact lenses are often called gas permeable. Furthermore, these contact lenses have many positive properties.
Hard gas permeable contact lenses are manufactured from special materials, which are based on silicone. Gas permeability of these materials is several times higher than of the materials, that are used for production of soft contact lenses. Therefore, modern hard contact lenses are absolutely safe for eye health, as they have minimal effect on corneal shell. These contact lenses are used in the following cases:
- Сompound astigmatism;
- For orthokeratology correction.
Advantages of hard contact lenses
- Hard contact lenses can save their original shape, because they are made from hard materials. They do not deform while blinking and provide a stable quality of vision;
- It is much more easier to take care of hard contact lenses than of the soft. Besides, they can not be torn;
- The surface of hard contact lenses has high tolerance for protein complexes, which are formedfrom lacrimal fluid and deposited on the lens. This propery of hard contact lenses allows to increase time of safe and comfortable wearing;
- The diameter of hard gas permeable contact lenses is slightly smaller than the cornea. This peculiarity helps to improve the process of tear exchange under the lens. Moreover, peripheral zone of the cornea remains available for permeation of oxygen;
- When you use hard contact lenses you have no need in rewetting drops. The material, from which hard contact lenses are made, does not contain moisture and so these contact lenses do not dry up in the wind or in warm room;
- Hard contact lenses are more economical than the soft, that require regular scheduled replacement. If you take care of hard contact lenses correctly, they can be worn for several years. You must change your contact lenses if you noticed that your visual acuity has changed.
Adjustment of hard contact lenses should be conducted by professional ophthalmologist, because it is very difficult to adjust contact lenses that will sit on cornea correctly by yourself. Also, only qualified specialist is able to help you to find suitable contact lenses, that will reveal their positive properties in the best way.