People who are suitable for contact lenses must choose regular products when buying contact lenses, and they also need to pay attention to the selection of contact lens parameters.
The first thing is that the prescription of the contact lenses must be accurate. If the prescription is not appropriate, long-term wear may affect the health of your vision. In the case of astigmatism, if the astigmatism is not high, you can use regular spherical contact lenses, but if the astigmatism is too high, it is better to customize the contact lenses with astigmatism design.
It is important to note that the prescription of frame glasses is known, and you should not buy contact lenses directly based on the known prescription. Because frames are worn on the bridge of the nose, there is a certain distance between them and the cornea, called the ocular distance, and frame prescriptions differ from contact lenses worn directly on the cornea. Contact lens prescriptions need to be converted on the basis of frame lens optometry.
Next is the base arc of the lens. The base arc is the radius of curvature of the lens, the size of the base arc and the steepness of the inner surface of the lens, the smaller the base arc is steeper, the tighter it will be in the eye. The smaller the base arc, the steeper it will be and the tighter it will be in the eye. If the base arc is not appropriate, it will reduce wearing comfort, so the size of the contact lens base arc needs to be chosen based on corneal curvature measurement parameters.
In addition, oxygen permeability and water content are two parameters that should not be ignored. The better the oxygen permeability, the more the cornea will be able to "breathe comfortably". Usually, the thinner the lens, the better the oxygen permeability, and the higher the water content, the higher the oxygen carrying capacity, but because it needs to keep the lens moist, it will draw moisture from the eye and cause dryness. Therefore, both parameters need to be taken into account, and different people need to evaluate their own situation and choose under the guidance of a medical professional.
Finally, in terms of comfort and safety, the shorter the disposable cycle, the cleaner the lenses are and the less likely they are to cause eye infections.
- Jul 31,2020
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