If you are new to eyeglasses, you may wonder how they correct your vision. Eyeglasses look pretty simple, but a lot of technology goes into correcting your vision and make them as perfect as possible. Eyeglasses have been around for hundreds of years. However, they were limited in what they could do. Modern eyeglasses correct a variety of issues that would have been difficult to solve in the past. If you wonder how a thin piece of glass can help you see better, continue reading.

Eyeglasses Reposition Images

When you look at an object, the light enters your eye and falls on the retina. Then, the optic nerve sends it to your brain. If your eye's structure is mostly normal, the image should be clear. However, many people have a flaw in their eye structure. In their case, the image falls short of the retina or overshoots it. Or, the image may be distorted by a flaw in the cornea. Eyeglasses help refocus the light so that it falls on the retina like normal.

Eyeglasses Are Plus or Minus

When you read your prescription, you may notice you have a negative or positive number. Negative numbers are for the concave lenses that correct nearsightedness. Positive numbers are for convex lenses used to correct for farsightedness. If you also have astigmatism, also known as a refractive error, your lens will be more cylindrical.

The lens shape plays a huge role in directing light and images on your retina. The concave minus lens spreads the light away from the center of the lens and pushes the focal point back. Convex lenses do the opposite by bending the light towards the lens center and drawing the focal point inward. Cylindrical lenses straighten the light rather than converging it to a point from two directions.

Eyeglasses Need Precise Measurements

Because eyeglasses can be complicated, your optometrist needs to take precise measurements of your vision and eye structure. The optometrist uses various machines to determine the shape of your eyeglass lens. All those "better or worse" questions help fine-tune your prescription. The more complicated your prescription, the more precise the measurements need to be.

Eyeglasses have improved so much over the years that most people with vision problems can benefit from them. On top of their improved optical qualities, their materials are also more advanced. You can choose from so many options, including reduced-glare and impact-resistant glasses. Chances are there's an eyeglass frame and lens out there that fits your lifestyle. Contact your optometrist if you need to upgrade your eyeglasses.