Matching glasses online should be prepared to facilitate the selection of appropriate glasses online. For high myopia, glasses online do not pursue large frames. The larger the frame, the thicker the lens edge, and it is not beautiful. If you want the lens not to come out of the frame, it is preferable to choose a frame with thickened side edges. The three digits A-B-C on the lens leg represent the width of a single lens, nose distance, and lens leg length.

When selecting medium to high myopia, the width of a single lens frame (i.e., A) should not exceed 50. Controlling it within 48 is good for the eyes, and the lenses will not be too thick.

Frame selection formula: (single lens width+nose distance - left and right pupil distance) ÷ 2=the best matching value. The smaller this value, the more suitable the frame is for you. It is best not to exceed 5, and less than or equal to 3 is the best.

Lens selection: mainstream refractive index of lens: 1.56-1.61-1.67-1.74. The higher the refractive index, the thinner and more expensive the matched lenses are. However, the refractive index is small, the Abbe number is higher, and the imaging clarity is better. Therefore, it is not necessary to match 1.74 for medium and low degrees. Firstly, it is expensive, and secondly, the imaging effect is not as good as that of low refractive index. Choosing low refractive index is better.

Height matching requires sacrificing some clarity in exchange for thinner lenses.