Although both glasses and contact lenses can correct vision, the degree of glasses and contact lenses are not exactly the same. If you do not pay attention to this problem and buy contact lenses directly according to the degree of the frame glasses, you may experience various discomfort symptoms due to the inappropriate degree. So, how should the degree of frame glasses be converted into the degree of contact lenses?
In fact, the inconsistency of the degree of contact lenses and frame glasses is mainly caused by the difference in the distance between the lens and the eyeball. The lenses of frame glasses are separated from the eyeball by a certain distance, and the contact lens is directly attached to the eyeball, almost no distance from the pupil, and there is even a tear mirror formed by tear filling inside the lens, so the degree of the frame glasses needs to be passed through. Conversion to get the degree of contact lenses. The deeper the degree of myopia, the more obvious the difference between the two degrees.
Under normal circumstances, when the myopia is below 400 degrees, the degree difference between the frame lens and the contact lens is small, and it can even be ignored under the action of the tear lens. However, when the myopia reaches between 400 degrees and 500 degrees, it is generally necessary to subtract 25 degrees from the degree of the frame glasses as the degree of contact lenses. By analogy, between 500 degrees and 700 degrees, you need to subtract 50 degrees; between 700 degrees and 900 degrees, you need to subtract 75 degrees; and when you are above 900 degrees, you need to subtract 100 degrees to get the invisible Degree of glasses.
Although the conversion of degrees is a bit troublesome, in order to more accurately correct vision and control the growth of degrees, everyone must do a good job of optometry and degree conversion. If you have any questions in this regard, you can consult an ophthalmologist or optometrist.