Optometry for prescription glasses
The key prerequisite for proper glasses is accurate optometry. In foreign countries, professional optometrists are generally required to be qualified to issue prescriptions for optometry. However, this is not very standardized in China. Many optometrists have only been trained for a short period of time and do not have the basic knowledge of ophthalmology. For some complex situations, they may not give a proper prescription for glasses. Therefore, optometry should choose a qualified institution. If you are adolescents, people with high myopia, people with anisometropia, etc., you may need to dilate your pupils for optometry. It is best to go to the optometry center of the hospital for optometry.
What Are Adjustable Glasses?
Are you over age 40 and unhappy with your current glasses for the presbyopia correction? Most people with nearsightedness, farsightedness, or astigmatism need progressive lenses to see objects clearly. But some are frustrated by the relatively limited field of view these and other multifocal lenses provide for intermediate and near vision.
And, those people with presbyopia also have problems. They often are frustrated by forgetting to bring their reading glasses or are constantly needing to put them on and take them off to see clearly at a different distance.
If you also have the same trouble, here is some good news. You can use multifocal eyeglasses to solve these problems and give you clear, unobstructed vision at any distance with just a simple turn of a dial inside the eyeglasses frame.
And these glasses are called adjustable glasses or adjustable focus glasses. They are a versatile and affordable solution to correcting minor vision problems. They compensate for presbyopia and other refractive errors like farsightedness and nearsightedness. They are non-prescription glasses designed for everyday use.
You can see the top to look far away and look down to see near objects clearly because different portions of lenses offer different types of correction. With adjustable glasses, you have one focal length that varies depending on where you are looking.
Anyone can wear adjustable glasses, but they are especially beneficial for people who cannot afford regular glasses or for those who live in areas where regular glasses are not accessible.
Parameters of lens material selection
Abbe number
Since the refractive index of the lens material varies for the light of different wavelengths, and white light is made up of various colors of light of different wavelengths, the dispersion phenomenon occurs when the lens refracts white light. The dispersion coefficient is an important index to identify the sharpness of lens imaging, which is usually indicated by Abbe number (Abbe number = dispersion coefficient). The larger the Abbe number, the smaller the dispersion, and vice versa, the smaller the Abbe number, the larger the dispersion, and the worse the resolution of the image.
Impact resistance
Humans have been using glass lenses for about 300 years, and it was not until 1947 that the first resin lenses made of CR39 were produced. A big reason for using resin lenses is their safety, i.e. impact resistance. Only lenses that pass the Drop Ball Test are considered safe. Combining the above two parameters, we can compare different lenses.
How to Keep Glasses from Slipping
Stick-on Nose Pads
Nose pads would be a good choice to prevent glasses to slide down your nose. Hence, you can stick a pair of rubber pieces in the nose pads of your glasses or you can choose a pair of glasses with rubberized nose pads. If you want to try a pair of nose pads glasses, the Koalaeye Optical may be a good choice. The rubber nose pads will make you feel steadier and better and the additional resistance on the nose pad will surely provide more support. So, if your glasses often slip down from your nose, try this way.
Wax Coating
To keep glasses from slipping, you can try wax coating which is a smart move. Use the wax on your nose pad area along with the temple where the glasses come into contact with the skin. In general, it works fine and it is nearly invisible.
Temple Ear Hook
The temple ear hook is a good way to keep glasses from slipping. It can provide mechanical support behind the ear and you will feel the support from the back of your ears. But the drawback of the temple ear hook is that it is quite visible. When you take off the lenses, you need to lift the temple higher so that the ear hook could clear the ear’s crest. Besides, the cheaper one might cause some discomfort to the back of your ears because of the pressure.
Rubber Bands and Hair Ties
To keep glasses from slipping, you can also try hair ties and rubber bands. You can tie one around the temple tip behind your ear so that it can provide both slight mechanical support and friction forbidding your glasses from moving around. What’s more, this is a low-cost method.
Have a try and confirm the front and side of the glasses.
Confirmation data: pupil height, flat frame surface, size of frame surface, the harmony of nose arc, the contact area of nose support, size of temple bend. Finally, remember a big principle: You should have no sense of pressure, and in a small range of motion, the frame does not shift. Good glasses should be perfectly integrated with the face so that people can not feel the existence of glasses. Good design is invisible. The lens above 800 degrees will be slightly heavy, so it is not recommended to choose the elastic temple and smooth metal temple. The temple is too slender, and at the same time is all metal, easy to slide frequently.
Why should you clean the eyeglass case?
Although the eyeglasses case is used less, it can not be separated from the glasses. If it is not cleaned for a long time, it will affect appearance and carry a lot of bacteria.
Silhouette Racing Collection 5502 BP 4540
With a metal frame and versatile blue, these Contour Racing series 5502 BP glasses will be your favorite glasses. The simple frame design ensures that these glasses are easy to repair. So you can wear it comfortably all day without enduring the endless squeezing and slipping of the substandard frame.
