Views:25 Author:Site Editor Publish Time: 2020-12-10 Origin:Site
1. Shape and size:
Goggles come in hundreds of shapes and sizes, from the smallest for competitive swimming (such as the typical Swedish goggles) to the largest for diving or snorkeling, also called masks. These small glasses can fit the eyes well, and it has less resistance to advance in the water, but after long-term use, people will feel uncomfortable and leave marks around the eyes. Large glasses have a much wider viewing angle, which makes them more suitable for recreational or diving use.
After determining the size and shape, the first thing to do is to ensure that these two parameters fit comfortably to the eye socket or facial contour, because each person's parameters are different, please check whether the surface in contact with the skin is adherent. You can put it around your eyes without swimming goggles. This is called a "suction test".
When buying glasses, we must also consider other factors that the nose clip between the two lenses is extendable or adjustable, so that the glasses fit the eye sockets well and will not rub the bridge of the nose or the nostrils of the face. We will also check the straps of the glasses so that they can be easily adjusted around our heads.
2. Structural materials of swimming goggles:
Currently, glasses with silicone gaskets or seals and polycarbonate plastic lenses (PC) dominate. Silicone is a strong and soft material, it adheres easily to the skin and is easy to clean. Polycarbonate is a very impact-resistant material, can withstand high temperatures and is very transparent.
But these materials are not the only materials. Depending on the model or manufacturer, different parts of the glasses use different materials. Therefore, we can also find polycarbonate frames, neoprene or silicone straps, thermoplastic rubber (TPE) seals and cellulose levulinate (CAP) lenses. CAP is a cellulose-derived plastic that has better properties than other plastics, such as its flexibility, a slightly lower refractive index and it does not cause allergies. However, they suffer greater degradation when exposed to the environment.
3. Lens treatment:
According to the scene where the glasses will be used, the color of the lens should be considered. The color of the lens may change with fashion, but it is recommended to use certain colors for general or specific purposes. If you want vision without changing color and contrast, you can choose a neutral color, such as gray or transparent. It is recommended to use green or brown lenses in outdoor sports because they can increase contrast and minimize color distortion.
On the other hand, if our favorite swimming place is outdoors (summer swimming pool, sea, etc.), it is strongly recommended that the lenses have UV A and sun AV B UV protection to avoid eye injuries as much as possible.
The lenses of some swimming goggles are subjected to another anti-fog processing, also called "anti-fog", which prevents them from fogging due to temperature changes. However, the effects of these treatments are not obvious, and they can only last for several baths, so they are usually supplemented with anti-fogging agents.