Introduction
Your eyes can lose their level of sight for a variety of reasons. Sometimes it can just be because of age; other times it may be a disorder or disease that causes the eyes to become weaker. Whatever the case, the first treatment for weak eyesight are eyeglasses. Eyeglasses have been around for centuries, but with time they have slowly evolved into the modern day version of what we see in vision clinics and stores worldwide. However, even with time, the basic ways in which the eyeglasses work have remained the same.
The Eye
To understand how eyeglasses work, you must first understand how the eye itself works when it comes to sight. When you look around you and see your surroundings, you are actually seeing different types of light reflections. This light travels off the objects, through the cornea, through the lens, and onto the retina in the back of the eye. The light has to hit the retina directly, or the picture of what we see becomes blurry.
The Problem
If the light hits perfectly onto the retina, then you have perfect vision. However, this is not usually the case. Different issues with the eye can cause the light to not hit the retina directly. The length of the eyeball may be too long or too short, there may be a problem with the lens of the eye that focuses the light onto the retina, or your cornea may not be shaped correctly. All of these issues cause the light to hit the retina incorrectly, causing blurry vision.
How Eyeglasses Help
Eyeglasses are pieces of equipment that help the eye refocus the light back onto the retina. They do this by refracting or bending the light. When the light hits the eyeglasses, the glasses are formed in such a way to redirect the light in an angle that hits the retina. This angle is determined by the optical power of the eyeglass prescription, which is measured in diopters. The higher the amount of diopters, the greater the lenses bend or refract the light. An eye doctor will use a piece of testing equipment called a phoropter to determine how many diopters are needed to refract the light at just the right angle to hit the retina straight on. Once the light lines up, the vision becomes clear.