Contact Lens Materials - Nesofilcon A and Omafilcon A
Nesofilcon A is super water glue. This is the proprietary material of Bausch & Lomb and is now used in only one product, the Bausch & Lomb Pure Suncast (launched in the US in 2012). Water content is 78%, and the oxygen permeability is DK/T =42.
Through PC Technology, the Omafilcon A material contains substances that mimic the composition of cell membranes--- including human eyeball cells, and locks water, and prevents dryness.
Adjust the nose pad
The height of the nose pad is adjusted by first holding the glasses with one hand and holding the nose pad with pliers with the other. Then the pliers are lifted up and the nose pad is moved down until the glasses are in the correct position on the face. The asymmetrical adjustment method is to first hold the frame of the eyeglasses with one hand, the other hand clamps the nasal plate with pliers. Then twist it in the direction of the correct tray position so that the surface of the tray is in contact with the two sides of the nose. Wrap one side of the lens of the glasses to be operated with a cloth first to prevent the screwdriver from slipping and scraping the lens during the operation. Don't scratch your glasses by adjusting your nose pad.
Why are some glasses expensive and others cheap?
Lenses do not regulate vision, but some progressive lenses can help the ciliary muscles to adjust. The quality of the lens is mainly determined by the transmittance, the surface, the aspherical surface, the refractive index, the coating quality.
The higher the refractive index, the thinner the lens, and the more expensive the price, for some people with high degrees, the lenses also play an aesthetic role. Commonly used are green film, and some are purple film, gold film, etc. How much cheaper is a relative number, and there are many other factors to consider besides price.
What difference do mono-focal glasses and multi-focal glasses have?
A mono-focal lens is a lens with one focal point. Usually, the myopic far-sighted presbyopia that we see belongs to mono-focal glasses. There is only one diopter on one lens, and this is the single focal point. Multi-focal glasses are lenses that have multiple focal points, that is, multiple diopters. Both mono-focal glasses and multi-focal glasses are visual correction tools, but mono-focal glasses can meet basic vision needs, like fatigue relief, control of depth of diopters, and focus on different distances such as the need to see far and near.But because there are many different diopters on a multi-focal glasses lens, so the elderly can not only see far after wearing. When they see close distance, they do not need to take off glasses or wear reading glasses. Wearing multi-focal glasses is not easy to fatigue.
Founded by Giuseppe Ratti in 1917, Persol is a brand of glasses designed for pilots and race car drivers and is now known for its durable sports sunglasses. Persol is an Italian luxury eyewear brand specializing in the production of sunglasses and frames. It is one of the oldest eyewear companies in the world, originally catering to pilots and sports riders. Currently, the company sells durable sports sunglasses. Currently, all Persol plastic glasses are made in Italy using cellulose acetate. Persol has had an apparent influence in the sunglasses industry. It was Persol who pioneered the development of elastic frames.
What Is a Prism in Glasses?
Prism is triangular and made of plastic or glasses for the purpose of dispersing light into a spectrum or changing the direction in which light is reflected.
Prism lenses are special lenses that are prescribed by eye doctors and infused into regular lens prescriptions. The prism glasses do not include contain any focusing power, and therefore cannot any refractive errors. So, one of the most common uses for prism glasses is to correct diplopia or double vision. Double vision means someone sees two separate images of a single object. The prism glasses help to align the two images and correct the problem. The prism glasses can be used to improve binocular vision and reduce double vision, headaches, reading difficulties, and so on.
The frame of prescription glasses
At present, the more common materials for frames are non-metal and metal. Non-metals mainly include TR90, sheet material, etc., and metals include alloys, titanium, and so on. TR90 and sheet material are actually plastics, but they are firm and are not easy be deformed at room temperature. Also, they have good formability so that they can be made in many fashionable styles. The general alloy material has good firmness and flexibility, but the disadvantage is that it is easy to fade. The pure titanium frame is corrosion-resistant and very strong. It is about 40% lighter than the general alloy frame. It must be welded and electroplated in an oxygen-free state, which requires high equipment and technology. Relatively speaking, the price of TR90 and alloys will be lower, and pure titanium will be more expensive. You can choose according to your budget.