Ordinary consumers often only pay attention to aesthetic problems when choosing spectacle frames, in fact, the optical and metrological technical indicators of spectacle frames are very important for the comfort of consumers wearing glasses, best place to buy eyeglasses. The selection of frames must meet optical and metrological requirements.
- The geometric center size of the frame should be close to the distance between the pupils of both eyes (less than 4 to 10 mm is preferable).
Considering that the blank of the lens must be moved to the center of the cutting edge before it can be installed on the frame in front of the eyes, the position of the pupil is best to the geometric center of the eye frame, with less than 4 to 10 mm. If the center of the lens is very large, it may cause prisms and other effects, affecting the comfort of wearing glasses.
- After wearing the lens, ensure that the distance between the lens and the eyeball is about 10mm.
If the lens is too far away from the eye, not only the optical effect changes, the wearer will also see the outside of the lens, causing positioning difficulties; If the lens is too close to the eye, the eyelashes will touch the lens, which is not only easy to cause lens blur, but also produce irritation. Therefore, it is best to ensure that the distance between the lens and the eyeball is about 10mm after wearing the mirror.
- The Angle between the front mirror of the glasses and the vertical line of the face of the wearer is about 4° ~ 18°.
The size of the Angle is related to the field of view. In general, the upper part of the frame should not touch the eyebrows and the lower part should not touch the face. If the frame cannot reach the required forward Angle, it is recommended to find a professional to adjust the nasal pad or replace the frame.
- The width of the glasses nose frame is moderate.
When consumers choose the frame, they can test it by themselves by keeping the head vertical and looking forward, and the frame can maintain a satisfactory position without any clamping on the mirror leg.
If the nose frame is too narrow, not only will the lens be too high in front of the eyes, but also the part of the nose frame that contacts the nose will be uncomfortable, and even cause temporary depression of the nose skin tissue; If the nose frame is too wide, the lenses will fall too low, and the legs will not be able to hold the frame in a normal position for long.
- Moderate leg length.
In principle, the curved part of the mirror leg should be just above the ear fold, but the pressure on the ear fold should be avoided.
If the length of the mirror leg is not enough, the glasses will tilt upward, and the tail of the frame will press into the back of the ear, making the wearer feel uncomfortable; If the length of the legs is too long, when the head is tilted, the tail of the frame will contact the back of the ear, and the glasses will fall off on their own.
It is worth noting that when trying on the glasses frame and estimating the length of the mirror leg, the frame should be kept at the correct forward Angle in the face. If the forward Angle is not taken into account when trying on, it will feel that the leg length is too short for a long time.
- Negative diopter (commonly known as myopia degree) the deeper the mirror circle is better.
- Generally speaking, those with large astigmatism should not use round frames.
- Taking into account the effects of visual aberrations, prisms, etc., ordinary consumers had better not choose a frame with too large an arc.
- For children, you can choose a transparent frame without a nose pad, and the nose pad is too high, which will show the characteristics of the nose bridge.
In addition, it is worth reminding that if consumers usually wear glasses with metal frames, they suddenly change to plastic frames, or vice versa, they will have a feeling of discomfort just wearing them. This is because the metal frame generally has a nose bracket, a nose bracket can adjust the vertical distance between the lens and the eye, often wearing a metal frame will be more adapted to the metal frame distance, and the plastic frame frame does not have a nose bracket, so the distance can not be adjusted, just wear will have a feeling of discomfort. Generally about a week for the adaptation period, the feeling of discomfort will gradually disappear or significantly reduce after the adaptation period, if still not reduced, it is recommended to find a professional consultation or re-use the original frame.
