How much do a pure titanium eyeglass frame cost?
For the plastic frame, without a fixed metal rod in the middle, the retail price of the exclusive store is 30 dollars or so. Resin-coated metal frames are inexpensive, 35 to 85 dollars in the store. Because pure titanium is more difficult to make, and the material is more expensive, the frame price often starts from 50 dollars. For example, the ordinary Seiko pure titanium eyeglass frame is about 85 dollars. In Europe and the United States and other developed countries, titanium spectacle frames are popular as a kind of high-grade decoration and fashion. In the past two years, the domestic began to be popular little by little. Titanium spectacle frame belongs to high-grade consumer goods, and the price is usually above 50 dollars.
The anti-reflection principle of the anti-reflection film
Anti-reflection Coating, known as anti-reflection membrane, is called anti-reflection coating in English, or AR membrane for short. The basis of anti-reflection is the wave and interference of light. The principle is: Two light waves with the same amplitude and the same wavelength are superimposed, then the light wave amplitude is enhanced. The two wavelengths and amplitudes are the same, but the superposition of wavelengths with different wave paths (similar to dislocation) cancels each other out. Therefore, the anti-reflection film plated on the surface of the lens uses this principle to make the reflected light generated by the front and rear surfaces of the film layer interfere with each other, thus canceling each other and achieving the effect of reducing reflection.
The Optical Center of A Lens
When wearing glasses, try to look through the optical center of the lens. This needs the cooperation of the neck, you can slightly lower the head when looking at the computer, to adjust the line of sight. The Center of optical glasses is divided into two kinds: 1 mm up myopic lens center is the most proper, of course, more than 2-3. And the most important thing is that the lens pupil high (about the two-lens optical center of the high and low) must be proper (that is, the right of the lens optical center is 1 mm, the left must be 1 mm. 2-3 mm is the same, what is the height of the pupil on the right side must be the same on the left side. The optical center of the presbyopic lens is 1 mm, the most proper.
Find the right size
The right glasses should sit comfortably on the bridge of the nose, not pressed against the forehead or cheeks. But they don't stay at the tip of the nose for so long that they slip while squinting or wrinkling your nose. The fit of the nose determines the distance between the glasses and the face. A proper fit should allow the lens to be between 14 and 24 millimeters away from the eyes. When you want to find glasses that fit, don't clip, don't slip, and don't lead to discomfort, you have to find out the size you need.
What to consider when buying eyeglasses?
You should think about that if the popular trend complies with your need for lens optics, the material, and its price, the famous brand. Check that if the producers have a professional cognition. The current frame is made of titanium, tungsten plate, carbon, metal, plastic, tortoiseshell, plastic, etc. Titanium is one of the best and most stable materials. The frames of other materials are easy to be corroded, discolored, worn, and deformed. No matter what kind of material you choose, it must be stable, safe, reliable, skin-friendly, light, strong, and non-deformable.
Testing of aspheric lens
The optical axis of the optical center just overlaps with the visual axis of the eye, which is the most ideal state. Because the light from the edge cannot form a focus on the optical axis, when the optical axis does not overlap with the visual axis (the difference is greater than 2mm), such unclear and scattered imaging results will occur. When choosing frames and aspheric lenses, you need to ensure that they fit correctly, to achieve the best visual and decorative effects. Simply put, due to the special design of the lens, we found through a calculation that the optical center should move down 1mm higher than the pupil for every 2° increase in front inclination angle. Otherwise, the wrong pupil height will cause the lens to look like astigmatism, and cause discomfort. For glasses with aspheric lenses, there must be an inclination angle after wearing. The specific angle varies from person to person.
How long does it take to get used to progressive lenses?
Because the adjustment of each eye is different, so there will be some differences in the adaptation period. It usually takes about two weeks to get used to it. Probably many young people are familiar with this kind of lens, so they adapt to them for only a week or so and can restore the normal visual effect. If it's been two weeks and you still feel that you can't see clearly, or you have the feeling of nausea, etc., then you need to test and adjust. You need to go to the hospital to see the specific case, to find out whether it is a quality problem of the sunglasses, or there are some artificial reasons. If there is a problem, we should also replace the lenses in time, otherwise, it may lead to the problem of visual fatigue. Therefore, it is still necessary to promptly confirm the case of optometry, and then replace the appropriate glasses.
