Eye Myths Sorted From Facts, From Reading in Dim Light to Eating Carrots

Almost every family has a saying about eyes. Do not read in the dark. Do not sit close to the television. Eat your carrots. Some of these sayings were passed down because they sounded sensible, and some are partly true. Others have no support at all. This guide sorts common eye myths into fact and fiction, using the advice of the College of Optometrists on its public information site, Look After Your Eyes.

Reading in dim light will not harm your eyes

This is one of the oldest warnings, and the College of Optometrists’ guide to eye facts and fiction calls it fiction. It is harder to see in the dark or in dim light than in bright light. The effort can bring on a headache. But reading in poor light does not cause any harm to the eyes.

The saying still carries a small lesson. If a child keeps reading in a weak light, the better answer is a brighter light, so the task is more comfortable. The advice is about comfort, not about damage.

A contact lens cannot get lost behind the eye

People who wear contact lenses sometimes worry that a lens that slips out of place will travel behind the eye. The College calls this fiction. The membrane that covers the white of the eye, the conjunctiva, also lines the eyelids. The two are joined, so it is impossible for a lens to get behind the eye.

If a lens feels stuck, or the eye is painful or red, seeing an eye professional is wiser than searching at home.

Borrowing someone’s glasses will not damage your eyes

Many people have tried on a relative’s glasses to see what the world looks like. The College says that wearing glasses that are not your prescription will not harm the eyes. You may not see very well, and you may get a headache or double vision, but you will come to no lasting harm.

There is one important exception. The College advises that you should only ever wear glasses that are your own prescription when you drive. A headache is harmless on the sofa. Behind the wheel, clear vision matters for everyone on the road.

If you often feel that your glasses are not right, or the print has become harder to read, the answer is a new test and not a borrowed pair. A guide on who should be tested for blurred vision explains who needs one.

Too much television will not damage the eyes, but near work matters for children

Watching a lot of television, or sitting very close to it, can make the eyes tired and bring on a headache, especially if the room is dark. The College says it will not cause permanent damage.

There is a second part to this answer, and it matters for parents. The College adds that long periods of near work, such as reading and screen time, may contribute to the development and progression of short sight in childhood. Researchers do not yet fully understand why. One possibility is that time spent on near work takes time away from being outdoors. So the old warning is wrong about damage, but it points at something real. Regular eye tests remain the way to check a child’s sight.

Eye exercises will not replace glasses

Some people believe that exercising the eye muscles will let you throw away your glasses. The College calls this fiction. People normally need glasses because of the shape and size of their eyes. Exercises will not change that.

A person who relies on exercises may delay getting the correct glasses.

The iris cannot reveal your health problems

Some people claim that studying the coloured part of a person’s eye, the iris, can reveal their health problems. The College says there is no scientific proof of this.

It does point out a true connection. When an optometrist examines your eyes, the visit does more than test your sight. The optometrist also checks the health of your eyes, and looks for signs of some general health problems. That is a good reason to attend an examination, and a guide on what a dilated eye exam checks shows what a thorough one can involve.

You cannot wear out your eyes by using them

People sometimes say that too much reading, too much work or too many hours of use will wear out the eyes. The College says the health of your eyes has nothing to do with the number of hours you use them. A day of heavy use may leave the eyes feeling tired, but the hours do not decide how healthy they are.

If the tiredness is constant, or if it comes with blurred vision or headaches, an eye test is worth having.

Holding a book close does not damage a child’s eyes

Parents often worry when a child holds a book very close. The College says how a child holds a book has no effect on the health of the eyes. It does not necessarily mean the child needs glasses. Some children simply find it more comfortable to read close up, and their very good focusing ability makes it easy.

The same page makes a distinction. If a child sits too close to the television, it may mean that the child has difficulty seeing things that are further away. In that case, take the child to an optometrist. A guide to the signs a child cannot see the blackboard lists other habits worth noticing.

Carrots help, as part of a balanced diet

This is the one saying that the College does not dismiss. It describes it as partly true. Carrots are a source of vitamin A, which is important for the eyes, and they should be part of a well-balanced diet that supports all-round health. The College adds that poor nutrition has been linked to diseases such as age-related macular degeneration.

The College’s verdict is “some fact” and not “fact”. A balanced diet supports general health, and that includes the eyes.

Its separate page on eating for healthy eyes adds some care. A wide variety of colourful fruit and vegetables, including dark green leaves, is good for general health and may support good eye health. Even so, the College says there is no strong evidence about the effect of diet on eye health.

The same applies to the many supplements that are sold with promises about the eyes. The College says there is no good evidence that you should be taking them. A large trial in the United States found that certain nutritional supplements may slow the progress of age-related macular degeneration in some people, but it is not clear that this applies to the wider population. If you smoke, or have been exposed to asbestos, the College warns against supplements that contain beta carotene, because they may be harmful. Ask your optometrist before buying any supplement.

Weight is another part of the picture. The College says a healthy weight is good for the eyes as well as for general health, because being overweight makes diabetes and high blood pressure more likely, and these can affect the eyes.

Sunglasses do not make it safe to look at the sun

One more belief is worth correcting, because the harm it causes is painless. Some people think that dark sunglasses make it safe to stare at the sun, for instance during a solar eclipse. The College’s page on sun and ultraviolet light says otherwise. Looking directly at the sun may cause a solar burn of the retina.

• Do not look directly at the sun, even with sunglasses on, because sunglasses do not offer enough protection.
• Do not watch the sun, or photograph it, on a phone, a camera, a telescope or binoculars. Even the quick glance up to line up the shot puts the eyes at risk.
• Do not assume that damage will be obvious. Harm to the retina is painless, and it may not be noticed for several hours.

The College’s safe options are simple. Use eclipse glasses with specially made solar filters, and check that the surface is not scratched. Or make a pinhole projector. Put a small hole in a piece of stiff card and hold the card with your back to the sun, so the image of the sun falls on a sheet of white paper held behind it. Never look through the pinhole at the sun. A person who accidentally looks at the sun and notices blurring, distortion or changes in colour vision afterwards should contact an optometrist.

Outdoor play helps, and eyes still need protection

Sunshine is not only a hazard. The College says that scientific studies have shown that children who spend time outdoors are less likely to be short-sighted. Its advice is not to stop a child exercising outdoors, but to make sure the eyes are properly protected. It suggests a hat with a brim or a sun visor in bright sunlight, and good quality, dark sunglasses with UV protection. It also notes that exposure to ultraviolet light has been linked to certain eye conditions, including cataract.

How to judge a saying you have heard

A few habits help when you hear a new claim about eyes.

• Be cautious when a claim promises a miracle, such as throwing away glasses.
• Be cautious when it tells you to skip an examination. A sound source will normally advise a professional check for a new problem.
• Check whether the claim is about comfort or about damage. Many myths confuse the two.
• Take your question to an optometrist or an eye doctor at your next visit. They hear these sayings often.

When to see an eye professional

Whatever the saying, some signs deserve an examination. A child who holds things very close, sits close to the television or struggles to see the board should be seen. An adult whose reading has become harder, or whose glasses no longer feel right, should be seen too. Sudden changes in vision need care straight away and not a wait for the next routine test.

For questions about your own eye health, ask PEBS about an eye examination. Readers who would like to give can review the hospital’s donation methods.

A saying about eyes is worth repeating only if it survives a visit to someone who tests eyes for a living.

This article is general information and does not replace an examination by an eye doctor.