Glasses comprise two important parts, the frame, and the lens. The frame is what people refer to when they talk about glasses style – think round or square, big or small. The lens corrects the vision and prevents distortion when looking at objects up close or at a distance. In this article, we will discuss bifocal and varifocal lenses.
The Transmission of Light
Bifocal lenses transmit light from both eyes at the same time. This means that if you have a bifocal lens in one eye, it will transmit light from your other eye. In contrast, varifocal lenses transmit light from one eye at a time. If you have a varifocal lens in your right eye, only light from your right eye will be transmitted through it; if you want to see what is happening on your left side, you need to look through another lens specifically designed to transmit light from your left eye.
The Direction of Vision
With Bifocal contact lenses, both eyes can look at the same object simultaneously; thus, they provide better vision than varifocal ones when reading or driving because they allow us to look directly ahead while still being able to focus on objects close by or far away from us.
The Field of View
Bifocals provide a wide field of view, so you can see objects close up and far away without moving your head or eyes. varifocal contact lenses have a narrower field of view than bifocals because they contain more than one focal point. One advantage of this narrow field of view is that it helps reduce eyestrain because you don’t have to move your head around so much while wearing them.
The Width and Height of the Lens
The lens width and height differ on varifocals than on bifocals. Because they are made to fit over more than one lens, they are larger in circumference but shorter in length than regular glasses. Bifocals do not change shape as varifocal lenses do; they have two different prescriptions for each eye.
How They Look
Varifocal lenses can make it look like you have double vision when you are looking straight ahead or looking down at something near your feet or lower body area (called “bottom reading”). This is because there is a difference between the lines in each eye that makes up what you see through the glasses. Bifocals do not have this problem because there is only one line for each eye instead of two separate lines like with varifocals; thus, there is no double vision when looking straight ahead or down at something close by.
How they are made
Both bifocal and varifocal contact lenses are made using the progressive design (the same technology is used to make both). The difference lies in the design of the lens itself – how it’s cut and shaped.
Bifocal lenses have two distinct focal points, one for near vision and one for distance. A bifocal lens will have an upper section of clear glass (or plastic) that allows you to see things up close without removing your glasses. There will also be a lower section of prescription glass that allows you to see things farther away.
Varifocals are cut into three sections: one for near vision, one for intermediate range, and one for distance viewing. The “varifocal” part refers to the fact that there are three different areas on the lens, each with its prescription strength.
The difference between a bifocal and a varifocal lens is that in a bifocal lens, there are two distinct focal points whereas, in a varifocal lens, there are three. That’s not to say that designs with single focal points don’t exist: the most commonly used type of reading glass lenses are single vision lenses because such designs are more easily mass-produced at affordable prices. Typically, any design with two focal points will be denoted as “bifocal”.