What kind of glasses are bifocals?
Bifocals are mainly used in presbyopia correction, providing presbyopic opticians with a clear vision for both near and far use in one pair of glasses. The bifocal lens can be divided into two separate areas, with the upper part of the lens providing clear distance vision and the lower part providing clear near vision. The two regions of the bifocal lens provide different refractive forces, and the difference between these two refractive forces is the reading proximal addition, which compensates for adjustment during presbyopic reading.
Magnesium aluminum spectacle frame
One of the characteristics of magnesium-aluminum spectacle frames is that they are resistant to corrosion, sweat and wear. In addition, spectacle frames made of magnesium-aluminum are also rich in color and look very textured, so many business people like to use such spectacle frames to display Its own charm.
Eyemart Express is founded in 1990. The focus is to get you the right glasses at the right price. Eyemart Express is the only retailer with a lens lab in every store that can produce 90% of its glasses on the same day. There are more than 2,000 frames to choose from, including designer brands and safety glasses. At their online store, you can buy prescription glasses anywhere and have them delivered to your door. You can choose the best glasses at the right price and enjoy same-day service.
Why are eyeglass frames are so expensive?
Good frames and bad frames are very different just in how they feel. The bigger the brand company, the more money it invests in the design, research and development, production equipment, and equipment of the lens frame every year, so as to improve the wearing comfort and improve the combination and precision of the lens. Even if for the general assembly line, the processing process is also very complicated. The most expensive things to make by hand are labor and time.
What is hard coating on lenses?
Lenses are mainly added in two kinds of film: anti-reflection film and hard film (and some manufacturers produce anti-fogging film and mirror film, but not common). The anti-reflective film is mainly by coating the front surface of the lens with multiple layers of transparent materials with different refractive index and thickness to reduce the excess reflected light on the surface of the lens, by using the principle of light interference. The film can be applied to both glass and resin lenses. The way of hard film plating is usually a soaking process. After many times of soaking and cleaning, soaking in an organic solution containing ultrafine silicon element for a certain time, and then keeping it at a certain temperature for 4-5 hours, the fixed polymerization process of the film has been completed. The surface wear resistance of CR-39 coating can be increased by 2-4 pH, which is similar to the hardness of optical glass lenses.
Buy Prescription Glasses Online Step By Step
1. Before you can buy glasses online, you’ll need a current glasses prescription.
2. Select an online retailer, comparing online retailers like EyeBuyDirect and KOALAEYE until you find the best fit for your needs.
3. Shop for the perfect frames according to face shape, frame favorites, the budget, etc.
4. Once you’ve found your perfect frames, you’ll enter your eyeglasses prescription and pupillary distance to choose the lenses.
5. Read over the fine print on return/exchange policies and product warranties before you complete your order.
6. Having picked your perfect frames, entered your prescription information, added any lens coatings and upgrades, and checked your online retailer's warranty and return policy, it’s time to complete your order.
Features of progressive lenses
With the proper head position, the wearer can have a clear and continuous vision at all distances from the distal point to myopia through the progressive lens. When the eye moves from one area of vision to another, the eye adjustment process is natural and smooth, without any visual fluctuations. With natural vision and better adaptability, it is in line with physiological optics. The mid and near vision area is relatively small: Some wearers may feel that the gradient area of the progressive lens is smaller, which limits the width of the saccadic eye and requires increased head movement in order to achieve the same reading range. At medium and short distances, the wearer needs to coordinate certain head movements.