Eye Myths and Facts: 24 Common Beliefs Checked Against the Evidence

Few parts of the body attract as much folklore as the eyes. Grandparents warn that crossing your eyes will make them stay that way, adverts promise that exercises will let you throw away your glasses, and social media regularly claims that phone screens are blinding a generation. Some of these beliefs contain a grain of truth; many are simply wrong; and a few are harmful because they delay real treatment.

Below we examine 24 of the most common eye myths, grouped by theme, and explain what mainstream research and organisations such as the American Academy of Ophthalmology (AAO), the National Eye Institute (NEI) and the NHS actually say. Where the evidence is uncertain, we say so.

Food and nutrition myths

Myth 1: Eating carrots gives you super-sharp vision

Fact: Carrots contain beta-carotene, which the body converts into vitamin A, essential for the light-sensitive cells of the retina. In countries where vitamin A deficiency is common, it is a leading cause of preventable childhood blindness and night blindness, and supplementation saves sight. But if you already get enough vitamin A, eating more carrots will not improve your vision or let you see in the dark. The story was famously popularised during the Second World War, reportedly to explain the success of British night-fighter pilots, who were in fact helped by radar. Read more in vitamin A and night vision.

Myth 2: Supplements can prevent all eye diseases

Fact: The large AREDS and AREDS2 trials showed that a specific combination of vitamins and minerals can slow progression in people who already have intermediate or advanced age-related macular degeneration in at least one eye. They did not show a benefit for preventing AMD in people without it, nor for preventing cataract. Supplements are not a substitute for a balanced diet, not smoking and regular eye checks. Our nutrition for eye health guide explains which foods matter most.

Myth 3: Bilberries and blueberries restore eyesight

Fact: Bilberry extract is widely marketed for night vision, partly due to another wartime pilot story. Well-designed studies have not shown a meaningful improvement in night vision or eyesight. Berries are healthy food, but not a vision treatment.

Screens and modern life

Myth 4: Looking at screens will make you go blind

Fact: There is no evidence that normal use of computers, tablets or phones causes permanent eye damage or blindness. Screens can cause digital eye strain: tired eyes, dryness, blurred vision and headaches, mainly because we blink less and focus up close for long periods. These symptoms are uncomfortable but temporary. Regular breaks, such as the 20-20-20 rule, good lighting and correct glasses usually help.

Myth 5: Blue light from screens damages the retina

Fact: Screens emit far less blue light than the sun, and current evidence does not show that screen blue light damages the retina. The AAO does not recommend blue-light-filtering glasses for eye health, and a Cochrane review found no clear evidence that they reduce eye strain. Blue light in the evening may affect sleep, so reducing screen use before bed or using night settings may help sleep, but this is separate from eye damage.

Myth 6: Screens alone are causing the myopia epidemic

Fact: Myopia is rising rapidly worldwide, particularly in East Asia. The strongest evidence points to two linked factors: large amounts of near work (reading, studying and screens) and too little time outdoors in daylight. Studies show that more outdoor time reduces the chance of children becoming myopic. Screens play a role mainly as one form of near work and because they replace outdoor play. Genetics matter too.

Myth 7: Sitting close to the TV damages children's eyes

Fact: Children can focus up close more easily than adults, so they often sit close without harm. Sitting very close does not damage the eyes, but it can occasionally be a sign that a child is short-sighted and needs an eye exam.

Glasses and contact lens myths

Myth 8: Wearing glasses makes your eyes weaker

Fact: Glasses correct how light is focused; they do not change the structure of your eye. Many people notice that their uncorrected vision seems worse after getting glasses, but this is because they have become used to seeing clearly, not because the eyes have deteriorated. Myopia often progresses in childhood and adolescence regardless of glasses, because the eye is still growing.

Myth 9: Not wearing your glasses will strengthen your eyes

Fact: Going without needed glasses does not train the eyes to improve. In adults it simply causes blur, strain and headaches. In children it can be harmful: a child with a significant prescription or a difference between the eyes can develop a lazy eye (amblyopia) if not corrected during early childhood. Under-correcting myopia was once thought to slow progression, but studies have shown it does not, and may even speed it up.

Myth 10: Wearing someone else's glasses will damage your eyes

Fact: Wearing the wrong prescription briefly may cause blur, discomfort or a headache, but it does not cause lasting damage in adults. Children should wear only glasses prescribed for them. Cheap ready-made reading glasses are fine for many adults with similar prescriptions in both eyes and no astigmatism.

Myth 11: A contact lens can get lost behind your eye

Fact: The conjunctiva, the thin membrane covering the white of the eye, folds back to line the eyelids, forming a closed pocket. A lens can slip under the upper lid and feel lost, but it cannot travel behind the eyeball. It can usually be moved back with gentle massage of the closed lid and lubricating drops, or removed by an eye professional.

Myth 12: It is fine to sleep or swim in contact lenses

Fact: Sleeping in lenses that are not approved for overnight wear significantly increases the risk of corneal infection. Water, including tap water, swimming pools and hot tubs, can carry Acanthamoeba, a rare but devastating cause of keratitis. Follow the hygiene advice in our contact lenses guide.

Eye exercise and natural cure myths

Myth 13: Eye exercises can cure myopia and let you throw away your glasses

Fact: This is one of the most persistent myths, often linked to the Bates method from the early twentieth century. Refractive errors are caused mainly by the shape and length of the eye, which exercises cannot change. Reviews of the evidence have found no proof that exercises cure myopia, hyperopia or astigmatism. Some people notice small temporary improvements in how they interpret blurred images, but the refractive error remains.

Myth 14: Exercises can prevent or reverse presbyopia

Fact: Presbyopia is the natural stiffening of the lens with age, and it happens to everyone, usually from the early to mid-forties. No exercise has been shown to stop it. Reading glasses, varifocals, contact lenses or surgery are the effective options.

Myth 15: So eye exercises are useless

Fact: Not quite. Exercises are not a cure for focusing errors or eye diseases, but they have legitimate uses. Supervised vision therapy is an evidence-based treatment for convergence insufficiency, a condition in which the eyes struggle to work together up close. Breaks, blinking exercises, palming and focus shifts can make screen work more comfortable. Our review of what science says about eye exercises covers this in detail.

Myth 16: Natural remedies can dissolve cataracts

Fact: No eye drop, diet, supplement or exercise has been proven to reverse a cataract. Experimental drops are being studied, but none are approved treatments. Surgery remains the only effective option, and it is highly successful.

Habits and everyday behaviour

Myth 17: If you cross your eyes, they will stay stuck

Fact: Crossing your eyes deliberately uses the same muscles you use to look at something close. When you relax, the eyes return to normal. A persistent squint (strabismus) has other causes, such as problems with focusing, muscles or nerves, and it needs professional assessment, especially in children.

Myth 18: Reading in dim light ruins your eyes

Fact: Reading in poor light can make your eyes feel tired and cause temporary strain, but there is no evidence that it causes permanent damage. Good lighting simply makes reading more comfortable.

Myth 19: Rubbing your eyes is harmless

Fact: Occasional gentle rubbing is usually fine, but frequent, vigorous rubbing is associated with keratoconus, a progressive thinning of the cornea, especially in people with allergies. Rubbing can also worsen allergic symptoms and spread infections. If itching drives you to rub, treat the underlying cause.

Myth 20: Staring at the sun briefly, or during an eclipse, is safe

Fact: Looking directly at the sun, including during a partial eclipse, can cause solar retinopathy, a burn of the retina that may permanently damage central vision. Ordinary sunglasses do not protect you; only certified eclipse viewers are safe for direct viewing.

Myths about eye diseases

Myth 21: If I see well, my eyes are healthy

Fact: Glaucoma, early diabetic retinopathy and early macular degeneration usually cause no symptoms until significant, sometimes irreversible, damage has occurred. Regular comprehensive exams, as described in our guide to eye examinations, are the only way to catch them early.

Myth 22: Only older people get eye diseases

Fact: While many conditions are more common with age, children can have amblyopia, strabismus, myopia and, rarely, tumours or congenital cataract. Young adults can develop keratoconus, uveitis and diabetic eye disease. Eye care matters at every age.

Myth 23: Glaucoma always causes pain

Fact: The most common form, primary open-angle glaucoma, is painless and slowly steals side vision without warning. Only the less common acute angle-closure form causes sudden pain, redness and blurred vision.

Myth 24: Colour blindness means you see only in black and white

Fact: Complete absence of colour vision (achromatopsia) is very rare. Most people with colour vision deficiency, far more often men, have difficulty distinguishing certain shades, usually reds and greens. They see colours, just differently.

Myth versus fact at a glance

How to spot a new eye myth

New claims appear online every day. Be sceptical when a product or method promises to cure a refractive error or eye disease, relies on testimonials rather than controlled trials, claims doctors are hiding the truth, or asks you to stop prescribed treatment. Reliable information usually comes from professional bodies, universities and national health services, and it acknowledges uncertainty.

When to see an eye doctor