What are the origins of saddle bridge glasses?
Rimless glasses were introduced in 1880 and were popular until the 1950s. Rimless glasses made in 1880 and 1920 lacked a nose pad. Instead, they use a saddle bridge, so they were sometimes called saddle bridge glasses. Horses are the main means of transportation. Early rimless saddle glasses were designed to be close to the face. Rimless glasses with nose pads were introduced in 1921. The nose pad keeps the glasses farther away from the face. In addition, frames can be made much larger.
How to determine whether progressive lenses are worn correctly?
Once your glasses are back from the lab, the optometrist will let you put them on for an audition and make final adjustments to make sure they fit. If the prescription is not in the center of the lens, it will make it difficult for you to see clearly. The key is that the lenses match the wearer's eyes, especially the pupils. Before ordering a new lens, the optometrist takes two measurements: pupil distance and fitting height.
Difference between green film and blue film
In addition to the usual hardening, anti-fouling, anti-reflection, anti-radiation, and other functions, the green film has remarkable anti-ultraviolet performance, suitable for people who work outdoors for a long time to use. In addition to the general hardening, anti-fouling, anti-reflection, and anti-ultraviolet functions, blue film’s anti-radiation ability is very good, and it is suitable for computer workers and other people affected by radiation greater.
The coated lenses were originally produced in green, mainly to distinguish them from the uncoated lenses. At 515 nm, the reflection increases the reflectivity by about 2%, so there is a contrast, and the green film is seen in the reflection. This film is the most standard anti-reflective film, and it is the best and oldest one available.
How to Find Reading Glasses Strengths?
Some reading glasses also come with strengths. So, how do you know what strength reading glasses to get and how to find reading glasses strengths? The strength of all reading glasses is measured in dioptre, with units increasing by 0.25 dioptre depending on the power of the lens.
The reading glasses strengths range from +0.75 dioptre to +3.00 dioptre. Both lenses have the same power which is indicated by a permanent marking on the inside of the frame or with a removable sticker on the lens. So, you can find the reading glasses strengths of the glasses.
The important thing you need to notice is that when higher the number, the greater the power of the lenses is when choosing reading glasses. So, glasses with a marking of 1.0 are low power while those marking +3.0 are high powered.
Persol PO2469V
If you want the best men's glasses with the best name and price, there's an Italian designer brand Persol. The steel frames come in eight different colors, from bold black and gold to soft gray. These frames provide what Persol calls Meflecto, a flexible stem system that eliminates pressure on the head.
Common Problems with Varifocal Glasses
In this section, we will list some common problems with varifocal glasses. The most common problem with varifocal glasses is people being unable to focus on what they need to. Losing focus often leads to some discomforts such as headaches or dizziness when performing tasks that require quick changes in near and middle-distance focus.
Besides, some people also experience a sort of swimming feeling when they are walking. It may be caused by being very aware of the distortions in your peripheral vision as well as the reading portion at the lower part of the lenses.
So, how to use varifocal glasses? The best way is to keep yourself from looking downward as you walk. You may also experience soft focus at the edges of the lenses and need to move your head more to see near objects better.
Anti-fouling Coating
The lens coated with anti-reflection film is pretty prone to stain, and the stain will affect the transmittance of the lens. Microscopically, the anti-reflection film shows a porous structure, therefore, the oil is very easy to soak in it. The solution is to coat a layer of anti-fouling film with anti-oil performance on anti-reflection film. The film is very thin and will not change the optical performance of the anti-fouling film. The material is mainly fluoride. There are two processes, one is the immersion method, one is the vacuum coating method (the most commonly used).
