How Do Prescription Glasses Address Common Vision Issues?

While many people around the world need corrective lenses to see, not everyone understands what goes into making a pair of prescription glasses or even what causes vision problems in the first place. This guide will help you better understand common vision problems and how your glasses can help.

Why People Need Glasses

Most people who have vision problems deal with refractive errors, which means the eye is unable to accurately focus light on the retina. This is often due to the way the different parts of the eye is shaped or curved. There are four main refractive errors that a person may need glasses for:

Myopia

More commonly referred to as nearsightedness, myopia causes a person to have difficulty seeing objects far away while having no issues seeing items close up. This condition is usually caused by a long or oval-shaped eyeball or a cornea that is too curved, causing images to become focused in front of the retina.

Hyperopia

Hyperopia, or farsightedness, may have the opposite effect of myopia, causing the individual so see clearly items that are at a distance while struggling to see up close. However, more severe cases can cause blurry vision at any distance. This refractive error causes the eye to focus images behind the retina as opposed to on it, often due to a short eyeball.

Astigmatism

If the surface of the cornea has an irregular curve, that can cause distorted vision at any distance. This condition may accompany either hyperopia or myopia. It can sometimes develop due to a condition called keratoconus or due to an eye injury.

How Lenses Work

The type of lens used depends on the vision problem an individual has. When reading your prescription, you will see the abbreviations OD or RE, which refers to the right eye and OS or LE, which refers to the left eye. Sphere measurements are used to describe how near or farsighted the individual is, cylinder measurements show the amount of astigmatism, and axis shows the direction in degrees of astigmatism.

There are three types of lenses used to address different refractive disorders:

• Concave lenses are indicated with a minus symbol and used to correct nearsightedness. They are thinnest at the center of the lens.
• Convex lenses are marked with a plus symbol and are thickest at the center. They are used to address farsightedness.
• Cylindrical lenses are curved in a specific direction for people with astigmatism.

How Frames Work

There are a variety of frame types that people can choose from depending on their style preferences and needs. Sports prescription glasses are designed to prevent slippage in motion and may include a strap to keep the frames in place. Safety prescription glasses are made from durable, flexible materials that can withstand impact in hazardous work environments.