Refractive Error vs. Visual Impairment: What’s the Difference?

37
0
man-in-eyeglasses-looking-at-camera-squinting-eyes

Many people think that just because they wear prescription contact lenses or eyeglasses, they are visually impaired. While wearing prescription eyewear for vision correction isn’t normal, having a refractive error and being visually impaired are two distinct conditions.

If you’re confused and wondering how to separate the two, then don’t worry. Lens.com is here to help you. In this post, we discuss the differences between refractive errors and visual impairment.

What is a refractive error?

human-eye-closeup

To understand what a refractive error is, you must understand how vision works under normal circumstances.

Light passes through the cornea and the lens first. The two work together to focus light onto the retina. The retina then turns this light into electrical signals that travel from the optic nerve to the brain. The brain then transforms these electrical signals into the images that you see.

A refractive error occurs when there is an irregularity in the shape of your cornea, which prevents it from correctly bending and focusing light onto the cornea. The result of this refractive error is blurred vision.

The four refractive errors are:

  • Myopia or nearsightedness – makes distant objects appear blurry
  • Hyperopia or farsightedness – makes nearby objects appear blurry
  • Astigmatism – makes both nearby and distant objects appear blurry and distorted
  • Presbyopia – refractive error related to aging that makes it difficult to focus on objects up close (like when reading)

Individuals with a refractive error may experience symptoms such as:

  • Blurry vision
  • Double vision
  • Eyestrain
  • Headaches
  • Difficulty focusing on certain objects

How is a refractive error diagnosed?

eye-exam

Eye care professionals (ECPs) can diagnose a refractive error by performing a routine vision screening. The screening involves a series of painless tests to determine if an individual has any vision problems.

If the ECP determines that the individual does have a refractive error, the ECP will provide treatment options to correct the refractive error. The most common treatments for refractive error include:

  • Eyeglasses – Prescription eyeglasses are one of the most common treatment options for refractive errors. Eyeglasses are simple and effective, although some individuals may consider them cumbersome and unappealing to wear.
  • Contact lensesContact lenses are also effective, but they require stricter care. Contact lenses are the best alternative for individuals who want an invisible way to correct their vision.
  • Refractive surgery – Refractive surgery is an elective surgery that permanently reshapes the cornea. Refractive surgery significantly decreases and even eliminates the need for corrective eyewear.

What is visual impairment?

Visual impairment is the decreased ability to see to such a significant degree that the individual can’t correct it with eyeglasses or contact lenses. According to the US Centers for Disease Control (CDC), an individual has visual impairment if no treatment can correct the individual’s eyesight to a normal level.

The most common causes of visual impairment include:

  • Uncorrected refractive errors
  • Diabetic retinopathy
  • Age-related macular degeneration (AMD)
  • Glaucoma

Experts also use the term visual impairment to describe any degree of vision loss, whether it’s partial or total vision loss. While some individuals can’t see at all (complete blindness), others are legally blind.

United States Federal Regulations defines legal blindness (also known as statutory blindness) as a central visual acuity of 20/200 or less in the better eye with the use of a corrective lens. Under the same regulation, having a central visual acuity of 20/200 or less means there is “a limitation in the field of vision so that the widest diameter of the visual field subtends an angle no greater than 20 degrees.”

In simpler terms, an individual is legally blind even if they haven’t lost all their vision, as long as they’d have to stand 20 feet from the object to see it as well as an individual with normal vision can see it from 200 feet (central visual acuity of 20/200).

Unlike refractive errors, US law considers visual impairment such as complete blindness and legal blindness as disabilities under the Americans with Disabilities Act (ADA).

Conclusion

Just because you wear prescription contact lenses or eyeglasses, that doesn’t mean you have a visual impairment. While having a refractive error isn’t normal, you shouldn’t consider yourself visually impaired. The term “visually impaired” only refers to individuals who are either legally blind or completely blind.