Blindness is a spectrum

Exploring the spectrum of vision impairment 

When you think about someone who's blind, you probably imagine that they live in a world of utter blackness with no light seeping in. Maybe as a kid you played games where you were blindfolded and got just a taste of what it might mean to have impaired vision. You may be surprised, then, to learn that vision impairment ranges across a wide spectrum.

Yes, some people live completely in the dark — but remarkably few compared to the number with low vision. In fact, 93% of people who are legally blind are actually able to see something. While many vision impairments can be corrected with glasses or contact lenses, not all can. Fortunately, most people only need minor corrections with contact lenses which deliver astonishing vision improvements to millions of people. If you're looking for great deals on contact lenses, reach out to us today to find your brand.

Every blind and visually impaired person probably gets tired of answering the question, "What can you see?" — so let's try to answer it here.

Defining vision impairment 

Vision impairment occurs when someone is unable to see as well as they should. In the United States, approximately 1 million people are legally blind. These people cannot see at 20 feet away what people with normal vision can see at 200 feet away — even if they're wearing glasses. In addition to these people, many others have impaired vision. Their sight isn't poor enough for them to be classified as legally blind. If someone can't see at 20 feet what normal people can see at 70 feet away (and that's with their glasses on), they're considered to have low vision.

Understanding blindness as a spectrum 

Not all visual impairments are the same. Some people are completely blind and unable to see any light at all, while others have a full field of vision, but everything they see is fuzzy and undefined. Along the spectrum of blindness, impaired vision may manifest in the following ways:

• Clear peripheral vision with no vision in the center of the visual field
• Everything appearing as blobs of color with little ability to distinguish shapes or borders
• A narrow field of vision with no or little peripheral vision
• Lack of depth perception
• Inability to tolerate light or glare
• Ability to see things in motion, with limited ability to see things standing still
• Double vision
• Blurred vision
• Constant flickering, flashing, or rippling in the visual field
• Visual distortions
• Limited vision in one eye only
• Vision that expands and contracts

Causes and types of vision impairment 

Many diseases or eye conditions can result in visual impairment and blindness. In all cases, something has disrupted the eye's ability to perceive light and send visual information to the brain.

Common causes of vision impairment 

The eye is a complex and delicate organ. It can be damaged through injury or disease in many ways, and it can also degenerate with age. Among the most common causes of visual impairment are:

• Glaucoma: This disease damages the optic nerve through a buildup of fluid within the eye. It can be treated through surgery and medication, but loss of vision incurred through glaucoma can't be reversed.
• Diabetic retinopathy: This complication of diabetes can lead to blindness. It occurs when high sugar levels damage the retina, leading to blurred vision, eye pain, and total vision loss. Controlling blood sugar helps, as may surgery and medication.
• Age-related macular degeneration: As some people age, the central part of their retina starts to degenerate. As a result, they lose their central vision while retaining peripheral vision. Surgery may help in some cases.
• Cataracts: Aging may also bring about cataracts, a clouding of the eye's lens (diabetes and steroid use have also been implicated as causes). Surgical replacement of the eye's lens with an artificial lens can restore full vision in most cases.
• Refractive errors: These occur when a misshapen eye causes light to hit the wrong part of the retina. Most people can have their myopia (nearsightedness), hyperopia (farsightedness), or astigmatism vastly improved with corrective lenses.
• Retinitis pigmentosa: This disease causes the breakdown of retinal cells that respond to light, leading initially to problems with night vision and eventually, in some cases, to blindness.

In addition, vision impairment can occur as a result of injuries incurred through fights, chemical burns, accidents, fireworks, sports mishaps and other causes. In all these cases, planning for eye safety ahead of time can keep something horrible from happening.

Vision impairment can also be a result of other medical conditions, including blocked blood vessels or strokes, tumors near or in the eye, and infectious diseases including shingles, toxoplasmosis, rubella, and syphilis. Poor nutrition can also cause some vision loss, as can amblyopia, or lazy eye.

Different types of vision impairment 

Because blindness is a spectrum, people experience several types of vision impairment. On one end of the spectrum is total, in-the-dark blindness. On the other end are the people who joke that they're "blind" without their glasses — and given that blindness is a spectrum, they're not totally wrong.

The different types of vision impairment include:

• Complete blindness: This rare condition means the inability to see light in any way.
• Legal blindness: Here, the central vision is no better than 20/200 (the person sees at 20 feet what normally-sighted people see at 200 feet).
• Low vision or partial blindness: People with low vision may have only central vision or only peripheral vision. Their vision may be hazy or blurred. They may also experience night blindness, or an inability to see in low-light conditions.

It might come as a surprise to learn that color blindness actually isn't a type of real blindness at all. That's because people who are color blind, while they can't distinguish all colors well, are still able to perceive light properly. People with normal color vision and color vision deficiency can both be on the blindness spectrum, however.

The impact of vision impairment 

The type of vision impairment you might experience can have impacts throughout your entire life. Many people have to make accommodations to their daily life while others find themselves coping with the emotional fallout of being on the blindness spectrum.

Daily challenges and adaptations 

People who find themselves dealing with partial or complete sight loss may have to use specialized equipment or make other adaptations to do their jobs. Some people might opt for braille keyboards while others turn to voice recognition software to get their work done. The ability to work from home has opened many doors for the partially sighted, who also find it easier to work without having to worry about transportation. Ever-improving assistive technology also helps make it possible for the blind and partially sighted to live a comfortable life and perform their jobs more effectively.

Emotional and psychological impact

Vision loss, especially if it occurs suddenly, can be a true shock to anyone. Someone diagnosed with blindness or vision impairment may want to seek psychological therapy or counseling to help them deal with the significant changes this can bring to their life. Many organizations and medical eye professionals can also provide help and support in making the transition.

Understanding vision impairment 

While the technology and medical advances surrounding eye care are amazing, you should do everything you can to keep your own sight healthy. If you find yourself along the blindness spectrum, you have lots of support available. Start with your own vision care team to learn what treatments, vision therapy, and tools can help you lead the best possible life.

FAQs

How is vision impairment diagnosed?

Your eye care provider will perform in-office tests to determine your visual acuity (or the sharpness of your central vision) and your visual field (or your peripheral vision). They will also test for eye diseases such as glaucoma and follow up on any other symptoms.

How can I be more inclusive and supportive of individuals with vision impairment in my community?

Great question! Start with an attitude of blindness awareness and treat all visually impaired people with respect. Offer help with mobility if they seem to need it, but step back if they decline help. If you walk with them, match their speed and ask them where they'd like you to stand. If a blind person has a guide dog, don't distract the dog at all — it's a hard-working canine!

You can also help by providing vision tips as to where objects are placed. Make sure they can reach objects easily and safely, and don't move them away without discussing it first.

Can vision impairment be treated or reversed?

In some cases, yes. People who are nearsighted or farsighted and/or have astigmatism can typically use glasses or contact lenses to treat their vision impairment and have unimpeded vision. Those with cataracts can often have their cloudy lenses replaced with artificial lenses, restoring their vision completely in most cases. Conditions involving the retina are more complicated to treat, and vision improvement may be partial or impossible, depending on the severity of each individual's condition.