Vision and Blindness: Common Myths Debunked

by Catherine Wall Emerson and Robert Wall Emerson

Let’s look at what is often considered common knowledge about vision, eyes, and blindness, and debunk some of the myths. Although we gain plenty of down-home, common-sense wisdom from our parents, a parent’s life is a busy one, and sometimes they don’t have the time to check all their facts. The fact is, much of what is considered common knowledge about our eyes is just plain wrong.

Don’t sit so close to the television, or you’ll strain your eyes.

Parents often seem to be concerned about “straining your eyes.” This is not surprising since blindness is often listed as the major fear people have (higher than death and taxes and just a bit higher than public speaking). However, kids can focus on things closer than their parents can (parents’ eyes are getting worse, not their kids’!), and while it might feel like a strain to adults to look at something up close, it might be just fine for kids.

As for the idea that harmful rays are being emitted from the television set, what most televisions are emitting is simply light.

Computers can damage the eyes.

Once parents get comfortable with the television set, they look for other potential threats in the environment. And what better candidate than that little-understood item, the computer? Who knows what kinds of weird rays come out of that thing?

This fear might have developed because of kids (and parents) spending so much time with their eyes and attention glued to a screen either for work or video games. This rapt attention can lead to less blinking, drier eyes, and fatigue. But these effects go away after a short break. It is like taking a walk break when jogging.

Reading in the dark will harm your eyes.

Again, it seems our poor parents are suffering under the delusion that if something is fatiguing for them, it must be bad for young people. If this were true, there would be no skateboards, snowboards, or parties that go past 9:00 p.m. In fact, everybody’s eyes operate a little differently. Some of us prefer dim light for reading; some of us prefer brighter light. Reading in the conditions that are most comfortable is best.

As we get older, our eyes tend not to be able to adapt as quickly or as much as they once could, and our operation distances might change so our reading preferences might also change.

If you cross your eyes, they will stay that way.

This is related to the saying that if you make a face it will stay that way. This is probably less a parental safety precaution than an attempt to deter poor behavior in kids. The muscles that control the eye will not stick in one spot when used, even if they are moved to the limit of their range of motion. That would be like saying don’t raise your arm or you won’t be able to lower it.

By the way, the muscles in the eye are the medial and lateral rectus muscles for horizontal movement (e.g., eye crossing), the superior and inferior rectus muscles for vertical movement (e.g., rolling your eyes at your kids), and the superior and inferior oblique muscles for eye rotation.

Eating carrots improves your eyesight.

Not all vision-related myths have to do with making your eyes worse. However, while vitamin A is necessary for vision (after combining with other chemicals in the retina, it flips between two forms when light hits it, initiating a chain of events that leads to an electrical signal being transmitted along the optic nerve), many other vegetables are good sources of vitamin A.

The idea that getting more vitamin A allows you to see in the dark may stem from the fact that the largest portion of the retina (the peripheral area) is populated predominantly by cells called rods, which are responsible for night vision (but insensitive to color). A few carrots might help if you are suffering from a deficiency of vitamin A, but that would be a rare occurrence.

Wearing glasses not designed for your eyes will damage your vision.

Well, not technically. But it is not going to lead to better vision, that is for sure. Wearing glasses not designed for you is like putting on a jogging suit three sizes too big or too small and then going out for a three-mile run. Your performance is going to suffer. If you do require spectacle correction, you can get an approximate solution by buying eyeglasses at the drugstore, but this will be like buying clothes off the rack. They may not fit quite right but you can live with it.

This is not true for contact lenses. Since contact lenses sit right over the cornea, a poor fit can lead to damage. In general, for spectacles or contact lenses, getting your fittings from a certified specialist (e.g., an optician or an optometrist) is the best bet.

Eye exercises will improve your vision.

This myth is a little trickier than the others. On the face of it, it makes sense. Once you know that your eyes and their movements are controlled by three pair of muscles, it seems reasonable that you can strengthen and therefore improve the function of these muscles through exercises, right? Well, not really.

Most reasons for poor vision are not due to the muscles, but muscles are the only parts of the visual system that might respond to “exercises.” Even those reasons for poor vision that are due to muscle imbalance or one muscle being too short, for example, generally need surgery for correction, not simply exercises.

Using your eyes too much will wear them out.

This was a stance popular decades ago and can still be found rattling around in dark alleys of popular belief. In fact, some state schools for the blind were once called “sight-saving” schools because it was thought that children with low vision should save what little vision they had left.

We know now that these children need to practice using their vision—what they can see, how to make sense of it, and how best to fit what vision they have into their daily lives. We do not have a limited amount of vision, just like we do not have a limited number of times our hearts beat. If that were true, we would all be counseled to lie still as much as possible in order to save our heartbeats and therefore prolong our lives.

Masturbation will make you go blind.

Can we figure out where this myth came from? Parents, in trying to deter what they see as bad behavior, often go for what rates as many people’s top fear—blindness. Fear not. Sex, either alone or with a partner, is not going to lead to blindness.

Then again, sex with the wrong people can lead to syphilis, which, if left untreated, can lead to blindness, insanity, and death.

Everybody with poor vision can have it corrected with glasses (and everyone with glasses has normal vision).

This double myth is based on a misunderstanding of the causes of visual impairment. Spectacles correct refractive errors (poor vision resulting from the eyeball being too long or short so the image is not projected properly on the retina) and a few associated problems. There are many other causes of visual impairment that involve the lens, retinal cells, the optic nerve, the visual center in the brain, or any of the many other parts of the visual system, none of which will be impacted by the wearing of spectacles.

A person may wear glasses to correct his or her refractive error but then be left with poor vision due to another cause. However, that person’s vision is better than it would be without the glasses.

Blind people’s other senses are extraordinary.

Some people believe in the compensatory model of visual impairment. This is a fancy way of saying that they believe that if one sense is lost, the others improve to make up for it. This is partly wishful thinking and partly a misunderstanding of observations. It sometimes seems as though people who are blind hear better or feel things more intensely than people with 20/20 vision. In fact, people who are blind must rely on their other senses to a larger degree to make sense of the world around them and so they are more practiced in using these senses.

If you spent as much time paying attention to these senses without vision getting in the way, you would become better at making sense of that information as well.

If you are blind, all you see is black.

It is actually pretty rare that a person sees nothing at all. You pretty much have to have the eyes enucleated (removed) and replaced with prosthetics to see nothing at all. Most people who are blind at least have light perception (they can sense when lights are on or can tell the difference between night and day). Others can see forms or shadows. Sometimes a bit of color can creep in. This may not seem like a lot of vision, but it can be handy in some cases.

There can be a lot of levels of vision in the grey area termed “legal blindness.” To be legally blind someone needs to have an acuity of 20/200 or a field of view of 10 degrees or less. The term itself is a little weird, like a judge decreed that someone is blind. Anyway, someone on the high end of the spectrum of legal blindness might be able to read large print and get around without too much trouble.

All people who are blind read Braille.

Braille is pretty handy but not everybody can or will learn it. Some people who are legally blind have enough vision to read large print or read regular print using a magnifier.

Others prefer to rely on electronic media with speech output. Still others prefer to have a family member or friend read to them since they can’t learn Braille (their fingertips may be too numb) or don’t have the opportunity to learn.

Guide dog users just tell their dogs where to go and then enjoy the ride.

It might seem like a person using a guide dog is being led, but it is much more of a partnership. The dog leads the person around certain obstacles (holes, low-hanging branches, puddles, and so forth) but it is the person who tells the dog which way to turn or where to go.

A person traveling with a long cane uses it to find out things about the environment and make decisions when traveling. The dog acts like an intelligent cane by perceiving environmental information and deciding what to do about it. The dog’s training teaches it to walk around obstacles without bothering to tell the person and to stop at level changes like a curb. This allows the person to pay more attention to location and where he or she needs to go so the person/dog partnership can travel more efficiently than the person/cane partnership.

You need to speak louder when talking to a person who is blind.

Pardon? Just because one mode of gathering perceptual information doesn’t work, that doesn’t mean everything else isn’t working just fine. This is a bit of an odd myth. No one assumes that because blind people can’t see, they can’t walk or move their hands. But they often think that they can’t hear well. And yet often those same people might also hold the belief that people who are blind have extraordinary senses. That is often how it is with myths—they are not based on fact or evidence and so can contradict each other.

And that brings us full circle. Myths about vision, or anything else, are propagated through word of mouth and by people not stopping to think about what they are saying (or not checking their facts). Common wisdom is sometimes common because it is too easy to come by. That which is too cheap may be worth what you pay.