Standard progressive lenses are multifocal lenses with three observation areas, farsightedness, intermediate vision, and nearsightedness. Unlike bifocals, there are no visible lines between each viewing area. They have a seamless, invisible design, where the optical power changes 'gradually' throughout the lens. Many people confuse 'bifocal' or 'trifocal' with 'progressive' but remember that bifocals and trifocals have visible lines in the lens, while progressive lenses do not. Because progressive lenses have no lines in the lens, they are more popular multifocal lenses than bifocal lenses.
The main observation area of the progressive lens is a far distance, the smaller area at the bottom of the lens is used for myopia, and the middle area in the middle is smaller. Standard progressive glasses are very suitable for general purpose glasses, focusing on hyperopia activities (such as driving and walking) and sufficient area in the lenses for nearsighted activities (such as reading and computer use). The left and right sides or 'convex corners' of the lens are deliberately blurred to achieve an invisible design. The clearest line of sight in the gradual process is from the center to the top of the lens.
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When do you need prism glasses?
If you experience symptoms of headache, dizziness, and nausea, then these symptoms may be caused by a subtle disorder between the eyes. This situation is called Binocular Vision Dysfunction(BVD). Double vision occurs in the situation that light enters the eye at the wrong angle and sends two different images to the brain. Some people have diplopia, where they can see only one image, and flat images are often blurry. Prism glasses can help to change visual deformities. Prism lenses can be helpful to prevent myopia and farsightedness in both eyes. If vision deteriorates in one eye, the eye muscle can use an external corrective prism to prevent blindness. Standard glasses are made of a combination of prisms that can correct the focal length errors and corneal curvature. The prism moves the image up and down or left and right to form an overall view.
This kind of glasses does not have a frame to wrap the eyeglass ring, only the metal nose pad, and temples, and the lens is fixed after being punched, which is relatively lighter. This kind of glasses is lighter and more fashionable and is the first choice for ladies in the workplace.
How to Choose Reading Glasses?
In this section, we will show you some tips for choosing reading glasses.
Find the right power. When choosing reading glasses, finding the right power would be the most important thing. All reading glasses will have signs or stickers indicating their power. In most cases, they will range from +1 to +4 diopter, in increments of +0.25. So, when choosing reading glasses, try the lowest power first.
Test-drive the glasses. If you have brought reading material with you, try reading it at a comfortable length. If you hold the material too far out to be able to read it, you should increase the power. Keep testing the differences powers until can read clearly at the distance that’s more comfortable for you.
Choose big frames the first time. When choosing reading glasses, you can choose the big frames for the first time. You may need larger glasses frames or lenses to really get the sweet spot of where the prescription is.
And if you have never worn glasses for eye conditions such as nearsightedness, farsightedness or astigmatism, it is likely you will be able to see well with non-prescription reading glasses. So, you can buy these non-prescription reading glasses.
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.
Difference Between Blue Light Glasses And Regular Glasses
Studies have shown that blue light is present in many light sources in our lives, especially on screens like cell phones, computers, and televisions. The main health effect of blue light sources is the damage to the eyes. Long-term exposure to blue light sources may cause lesions in the eyes. The harm of blue light to human health can be prevented by corresponding new technology products. Among them, the anti-blue lens is one of them. So how to distinguish between blue-light-blocking glasses and ordinary glasses?