The 13 things you need to know about your eye health

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“In terms of size, the bigger the better, because you’re not only protecting the inside of your eye, but the eyelids — the eyelid area is at a very high risk of skin cancer,” she adds, explaining that UV rays can also worsen dry eye and outcomes with macular degeneration and cause solar retinopathy — damage to the retina from looking directly at the sun. Additional sunglasses features such as tinted lenses to relieve eye strain and polarising lenses that reduce glare from flat surfaces and water may be better quality in more expensive sunglasses.

2. How bad are screens for my eyesight, and what can I do to counteract this?

Research last year found that between 55 and 81 per cent of people who sat in front of computers for extended stretches suffered eyestrain, which happens when the eye’s ciliary muscles, which change the shape of the lens to allow us to focus on a fixed point, become tired. This can lead to blurred vision, burning eyes, sensitivity to light, and headaches.

However, according to Dr Daniel Ezra, oculoplastic consultant at Moorfields eye hospital in London, “the most important issue with screens is dry eye [when our eyes don’t produce enough tears to stay wet]. The intensity and contrast of screens reduces our blink rate, which means the ‘windscreen wiper’ effect of the upper lid to spread tear film [made up of water, oil and mucus] over the eye surface happens less. This puts more pressure on the tear film, which evaporates.” Symptoms include stinging, blurred vision, burning and eye redness.

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“We are not biologically designed to sit staring at bright lights for hours on end,” Ezra says. He advises dimming the brightness of your monitor and taking a few minutes’ break for every hour of screen time; Dr Elizabeth Hawkes, consultant ophthalmic and oculoplastic surgeon at the Cadogan Clinic in Chelsea, west London, advocates the 20:20:20 rule. “Every 20 minutes look at an object 20ft away for 20 seconds,” she says. “Looking away encourages you to blink, so you’re replenishing your ocular surface and relaxing your eye muscles.”

3. I don’t work at a computer. Why have I developed dry eye?

Ageing and hormones may also be to blame. There is a “non-conclusive” link between dry eye and declining oestrogen levels, says Ezra — “HRT can be helpful”. He adds that blepharitis — inflammation of the eyelid caused by blocked oil glands that stop secreting — is another common cause. “In crude terms, the tear film is like a sandwich, with an aqueous layer and an oily layer on top. The oily layer stops the watery bit evaporating.”

Hawkes says that massaging your eyes morning and evening with cotton wool pads soaked in warm water will help to release secretions, adding that it’s essential to remove make-up before bed. Over-the-counter eye drops containing the tear substitute hypromellose may also help. Ezra says that minor surgery to insert microscopic plastic plugs in the lacrimal puncta — the openings in the eyelids where tears drain into the side of the nose — “block the drainage, which increases tear availability”.

4. Is an e-reader better for your eyes than scrolling a phone?

Yes, because most e-readers, such as the Kindle Paperwhite, use e-ink screens — made up of millions of microcapsules containing negatively charged white particles and positively charged black particles that mimic the effect of ink on a page — rather than the backlit LCD (liquid-crystal display) screen found in smartphones, which can strain the eyes in the same way as a desktop computer.

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A research article in the journal Plos One called E-Readers and Visual Fatigue found that reading on LCD screens reduces the blink rate and increases perceived visual fatigue compared with reading e-ink or a paper book. Unlike a printed book, of course, a Kindle’s text size can be increased, “so we recommend patients who have age-related macular disease [when the macula — the part of the retina at the back of the eye responsible for our central vision — is damaged, leading to dark spots and blurred vision] use them to keep reading,” Hawkes says. However, she stresses a Kindle is “still a screen” and advises reading a printed book where possible.

5. Will my child’s gaming habit and phone addiction mean they’ll need glasses younger?

Possibly. Staring at devices at close range can cause similar sight issues for children as it does adults. A study published last year in the journal Environmental Science and Pollution Research reported a positive link between smartphone usage and eye fatigue, blurred vision and irritated or burning eyes. Another study of children found that spending more than 45 minutes viewing books or screens at a distance closer than 25cm was associated with myopia, or near-sightedness — caused when objects further away look blurry because the eye refractslight rays inaccurately. This can be corrected with glasses.

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World Health Organisation guidance is to limit screen time to no more than one hour daily for children under five. Also, research has found that spending at least 13 hours a week outside reduced the likelihood of children becoming myopic. There is “a strong relationship between the development of myopia and being confined indoors”, Ezra says. “It could be when you’re outdoors the eye develops for longer distances.”

6. My eyesight was perfect until I turned 40. Now I can’t see my phone. Is this normal?

Unfortunately yes. As we age, the lens — a protein-filled disc that focuses light through the pupil at the front of the eye to the retina, the light-sensitive tissue at the back — stiffens, losing its ability to bend to focus on nearby objects, making words look blurry at close range. This is known as presbyopia, usually becomes noticeable by the early to mid-forties, affects nearly everyone by 50 and is such an inevitable part of ageing that, Ezra says, “you can almost measure somebody’s age based on how quickly their focusing power drops off”.

7. Can I get away with cheap reading glasses or should I always get my own prescription?

For those of us forever losing our readers, seven cheap pairs scattered around the house seem more useful than one £200 pair lost behind the sofa. And while Ezra says shop-bought glasses tend to be more “crude” — a £20 pair of off-the-peg readers might correct your vision to 95 per cent, compared with the perfection a £200 prescription pair offers — “the incremental improvement can be small, and whether it’s worth it depends on the individual. A decent optician will advise.”

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If you have other vision problems in addition to presbyopia — blurry distance vision, for example — off-the-peg readers aren’t suitable and you may need to see your optician to get bifocals, with two prescription strengths in a single lens. The strength of reading glasses is categorised in increments of .25 and typically ranges from +1.00 to +6.00. You could use an online tool such as readers.com to assess which number you need, or try on pairs in a shop until you find glasses you can read comfortably in, but opticians will check for general eye health as well as measuring your prescription.

8. Will upping my glasses’ strength make my eyesight weaker?

No, although repeated studies have found that people think glasses can somehow exacerbate vision deterioration. It is a “powerful narrative” — but false, Ezra says. “People think of glasses as being like using a crutch for support — if you don’t use your crutch your leg will get stronger. But eyes don’t work like that. They’re working just as hard with glasses.”

Hawkes adds that if you’re reliant on perfect vision for high-risk activities such as driving, going without glasses can be dangerous.

9. How often should I get my eyes checked?

Every two years, according to NHS guidance, although “if you have family history of eye disease, go at least once a year”, says Hawkes — not just to check if you need a new glasses prescription, but because opticians perform checks such as macular and optic nerve scans that can pick up otherwise undetected eye diseases such as macular degeneration and glaucoma (caused by fluid build-up that increases pressure in the eye, damaging the optic nerve that transfers visual information from the eyes to the brain, leading to loss of vision). “Sight loss is a late sign of many diseases. The earlier you pick them up, the better the prognosis.”

10. What are the surgery options to improve my eyesight?

Laser surgery — for presbyopia and long and short-sightedness — uses a laser to change the shape of the cornea, the transparent part of the eye that covers the iris and pupil and allows light to enter.

The surgery usually costs between £600 and £3,500 per eye and takes less than an hour. Recovery time is a matter of days and the biggest side-effects are dry eye and discomfort, “which is usually transient”, Ezra says. Results aren’t always permanent — your eyes may need lasering again in five to ten years, he says, “but for most it is very stable”.

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Then there’s lens replacement surgery — also for presbyopia, although it originated as cataract surgery — during which a surgeon makes a tiny cut in the cornea and extracts your natural lens before inserting a multifocal artificial lens that allows you to see at near and long distance. This can cost from £1,995 to £3,995 per eye.

The results are permanent and recovery time is similar to that after laser surgery. “More people are amenable to lens replacement surgery but the quality of the vision is not quite as good,” says Ezra, who adds that the risks are “more significant, such as vision loss and damage to the eye during surgery, but these are rare, at less than 1 per cent”.

11. Does eating carrots or leafy greens really help eyesight?

While eating carrots won’t, alas, help you to see in the dark, they’re rich in beta carotene and lutein, antioxidants that can help to prevent cell damage. Research in Jama (the Journal of the American Medical Association) found that those with the highest intake of lutein and another antioxidant, zeaxanthin — also present in spinach and kale — had a 43 per cent lower risk of macular degeneration, leading to dark spots and blurred vision, than those with a lower intake.

“It’s worth taking lutein and zeaxanthin supplements if you have a family history of macular degeneration,” Hawkes says.

Another key nutrient includes zinc — a mineral found in red meat, poultry and nuts — which helps to bring vitamin A from the liver to the retina to produce melanin, a protective pigment in the eyes. Vitamin E, plentiful in seeds and nuts, also protects the retina, with one study in Public Health Nutrition finding that more than 7mg of vitamin E daily, the equivalent to 27g of almonds, could reduce the risk of cataracts — cloudy patches that develop on the lens, causing blurred vision — by 6 per cent. However, the NHS-recommended daily allowance is 4mg for men and 3mg for women.

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Hawkes also recommends flaxseed, which is high in omega-3; it “has been found to improve the quality of the secretions of tear film from the [meibomian] glands in the eyelid. It is also good for retinal function at the back of the eye.”

Studies show that following a Mediterranean diet with lots of leafy green vegetables containing antioxidants can also delay the onset of cataract formation and macular degeneration, Hawkes says. She recommends that those with a history of thyroid dysfunction take selenium, which is a mineral found in brazil nuts and available in supplement form to improve symptoms of thyroid eye disease, when an overactive thyroid causes swelling of the eye muscles, causing the eyes to become pushed forward.

12. Will exercise help my eyes?

Yes — cardiovascular exercise improves blood flow, helping every organ to function properly, and eyes are no exception. “The eye has some of the smallest blood vessels in the body, so they are more sensitive to cardiovascular changes, and the outcome of poor cardiovascular function can be just as devastating as to other areas of the body,” Hawkes says.

An analysis of six studies published in 2020 in the International Journal of Ophthalmology Press found that physical activity can help to increase antioxidant enzymes in the eye and was associated with a 10 per cent reduced risk of cataracts. A 2021 study published in the Indian Journal of Ophthalmology found that 30 minutes on a treadmill reduced participants’ intraocular (eye) pressure (an increase can lead to glaucoma).

“The guidance is to get your heart rate up for 30 minutes every day,” Hawkes says. Cut out smoking; Ezra says it “causes hypoxia, which decreases the ability of the blood to carry oxygen and damages the eyes’ blood vessels, causing a variety of eye diseases including artery occlusions, leading to sudden vision loss”. He also advises limiting alcohol intake, which “can affect the eye in a number of ways, the most severe of which is probably optic nerve damage and damage to the macular — the most sensitive part of the eye”.

13. What about sleep?

Published in the medical journal BMJ Open in 2022, an observational study of 400,000 people aged 40 to 69 found that those who slept less than seven hours or more than nine hours a night were 13 per cent more likely to develop glaucoma, potentially because eye pressure increases when lying down, damaging optic nerves that connect the eyes to the brain. Other research has found a link between poor sleep quality and dry eye. “When your eye is closed the ocular surface is resting and able to repair the traumas of the day — the pollution, air conditioning, heat and stress it is under,” Hawkes says.