Besides being used as an accessory, glasses are mainly worn to be able to see things clearly. It means that they involve the understanding of the phenomenon of vision. Naturally, the human eye bears a special mechanism for viewing objects and if the eyesight gets weakened, glasses are used to improve it. Now-a-days, it has become easier to buy glasses online with the help of different online sites and mobile apps.
Working of the Eye
It is essential to know how a human eye works. The surface of human eye is known as Retina which is responsible for vision. When we look at something, the light rays focus on the surface of eye. If the person has no issue of eyesight, these rays will fall together directly on retina. For that, there are two requirements to get a clear vision:
- Image must shrink.
- It should be curved just like the surface of retina.
Two main eye parts, the pupil and cornea are used to shrink, focus and direct the light rays for forming a curved image. If they fail to do so, the vision will be blurry.
Problems of Eyesight
People with nearsightedness are unable to see distant objects whereas farsightedness results in an unclear close vision. The light rays in first case fall together in front of retina making distant objects invisible. In the second case, they fall behind retina. The vision might also be affected by astigmatism where the eye curvature is irregular in shape due to which a second focal point appears inside the eye. All these problems result in unclear vision.
Action of Glasses
The eyeglass lens is specially designed into curves. When light rays fall onto them, they are bent by the help of these curvatures. Due to this, the light rays are able to focus directly on the retina instead of behind or in front of it.
Types of Eyeglass Lens
Two main types of eyeglass lens are used:
For nearsightedness, convex lens is used. Their action involves bending the light towards top and bottom of lens due to being curved in slightly. Thus, the focal point is pushed back towards the retina.
Concave lens is used for farsighted individuals. It works by bending the light towards the center and the focal point is pushed forward.
Hence, these two types of lenses are used that help in improving the vision of eye and must be used as per the recommendation of the eye physician.
How to Pick the Right Glasses?
Many tests are done to check the optical parameters in detail and then prescription is made. By the use of online platforms, frames of the choice can be easily picked now. There are several smart apps for analyzing the prescription given by an expert that help to choose the suitable frame according to the parameters involved.
One of the main things to be kept in mind is that the glasses change the light rays received by our eye. If they are too strong or not of the right number, it does not mean they will damage any part of the eye. However, only a temporary headache due to improper vision or blurriness will occur.
Likewise, one must know that glasses are optical aids used externally and if someone has eye disorders, he must consult the eye physician before putting them on. Eye disorders include glaucoma, diabetic retinopathy, crossed eyes (strabismus), lazy eye (amblyopia) and others. Although, wearing glasses has become quite trendy now but picking out the right ones and getting your eyesight checked are essential for a safe experience.