Warning signs of eye trouble

Blurry vision, spots, glare at night - these are common eye complaints that can be harmless annoyances or an early sign of disease. In the slides ahead we explore several eye problems and offer two quick eye tests. You'll see the world through eyes that have floaters, cataracts, myopia and glaucoma. See an optometrist or your doctor promptly if you have any concerns.

Colour blindness test

Which number do you see in the far left? If it's "3", you probably have normal colour vision. If it's a "5", you may be have colour vision deficiency – also known as being colour blind. This view is simulated in the centre panel and represents a mild colour vision deficiency. Red-green colour vision deficiency is the most common type and affects around one in 12 men and one in 100 women in the UK. Complete colour blindness (very rare) is simulated on the right. No number is visible. Tinted glasses may help with colour blindness.

Short-sightedness (myopia)

Around 1 in 3 people in the UK are short-sighted. Risk factors include:

• Family history (one or both parents)
• Lots of prolonged, close-up work, such as reading
• Too little time spent outdoors in childhood

Trouble with driving, sports or seeing a school or college white board or the TV may ensue. Symptoms include headaches, squinting and fatigue. Myopia can be treated with glasses, contact lenses or surgery in some cases.

Long-sightedness (hyperopia)

Most of us are born with mild long-sightedness also known as far-sightedness, but normal growth in childhood often corrects the problem. When it persists, you may see distant objects well, but books, knitting and other close objects are a blur. Hyperopia runs in families. Symptoms include trouble with reading, blurry vision at night, eyestrain and headaches. It can be treated with glasses, contact lenses or surgery in some cases.

Presbyopia

Just like grey hair or wrinkles, trouble reading fine print is a sign of ageing. Called presbyopia - or "old eye" in Greek - symptoms typically appear in the 40s. The eyes' lenses become less flexible and can't change shape to focus on objects at reading distance. The solution: reading glasses, or bifocals that correct near and distance vision. If you wear contacts, one eye can be corrected for reading and the other for distance. This is known as 'monovision' and may also be possible via surgery.

Short-sightedness: What happens

Typically, an eyeball that's too long causes short-sightedness, or myopia, but an abnormally shaped cornea or lens can also be responsible. Light rays focus just in front of the retina, instead of directly on it. This sensitive membrane lines the back of the eye (seen in yellow) and sends signals to the brain through the optic nerve. Short-sightedness often develops in school children and teenagers, who need to change glasses or contacts frequently as they grow. It usually stabilises by the early 20s.

Long-sightedness: What happens

In long-sightedness, or hyperopia, the cause is often an eyeball that is too short. Light rays focus behind the retina, causing close objects to be blurry. An abnormal shape in the cornea or lens can also lead to long-sightedness. Children with significant hyperopia are more likely to have crossed eyes (strabismus) and may have difficulty reading. That's one reason why children have eye tests from birth.

Astigmatism

Your vision may be out of focus at any distance with astigmatism in one or both eyes. It occurs when the lens or the cornea, the clear "window" that covers the front of the eye, is not a perfectly curved shape. Light rays can be scattered in different points on the retina, rather than focusing on a single point. Other symptoms include headaches, fatigue and eye-strain. Glasses or contact lenses correct the problem, and surgery may be another option.

Refractive eye surgery

Do you dream of seeing clearly without glasses? Surgery to reshape the cornea can correct short-sightedness, long-sightedness or astigmatism with a success rate of better than 90%. People with severe dry eye, thin corneas or severe vision problems may not be good candidates. Possible side effects include glare or sensitivity to light. Laser surgery is available on the NHS for eye conditions that can lead to loss of vision if they are left untreated.

Glaucoma

You can't feel it, but rising pressure in the eye can silently steal your sight, a condition called glaucoma. There may be no symptoms until some peripheral vision is lost, so regular eye tests are critical to detect it early because any damage to the eyes cannot be reversed. Those at higher risk include:

• People of black-African or black-Caribbean origin
• People of Asian origin
• People with a family history of glaucoma

Fortunately, glaucoma can be treated with medication or surgery. Regular eye tests every one to two years after the age of 40 – or earlier if recommended – can help identify it early.

Glaucoma: What happens

In the most common form of glaucoma, too much fluid builds up inside the eye. That increases pressure and damages the optic nerve at the back - the bundle of one million nerve fibres that carry information to the brain. Without treatment, glaucoma can cause total blindness.

The bright yellow circle shows an optic nerve head that is damaged by glaucoma. The dark central area is the macula, responsible for finely-detailed central vision.

Macular degeneration

Age-related macular degeneration (AMD) damages, then destroys, the eye's finely-detailed central vision, making it difficult to read or drive. Symptoms can include a central blurry spot or straight lines that appear wavy. Detecting and treating AMD promptly can help slow vision loss. Being over 60, a family history of AMD, and smoking increase the risk.

Macular degeneration: What happens

In age-related macular degeneration (AMD), the central part of the retina, called the macula, deteriorates. In the dry form, doctors often see yellow deposits called drusen in the macula. As dry AMD progresses, the macular tissue deteriorates, gradually shutting down the delivery of images to the brain. In the wet form, abnormal blood vessels grow. They leak blood and fluid (seen here), causing scarring and further damage to the macula. Both types lead to a central blind spot.

Macular degeneration: Test

Cover one eye and stare at the centre dot in this Amsler Grid, from a distance of 30 to 40 cm. (You can wear your reading glasses.) Do you see wavy, broken or blurry lines? Are any areas distorted or dark? These are possible signs of AMD and should prompt an eye examination. Repeat the procedure for your other eye. While no self-test can substitute for an eye examination, this grid is used to help detect early symptoms of AMD.

Next:  See how this grid looks with AMD.

Macular degeneration: Signs

As seen here, the Amsler Grid can look quite distorted to someone with significant macular degeneration and may include a central dark area. Straight lines that appear wavy are also cause for concern, as they can be an early symptom of "wet" AMD, the more serious and fast-moving type of macular degeneration. Your optometrist will want to evaluate you right away, starting with a thorough dilated eye examination.

Diabetic retinopathy

Type 1 and type 2 diabetes can cause partial vision loss (seen here) and lead to blindness. The damage involves tiny blood vessels in the retina and can often be treated - but don't wait for symptoms. By the time they occur - blurry vision, spots, shadows or pain - the disease may be severe. For those with diabetes, an annual examination of the retina can detect early warning signs. The best prevention is keeping your blood sugar well managed.

Diabetic retinopathy: What happens

When high blood sugar levels go unchecked, it can damage the tiny blood vessels that support the retina. These blood vessels can swell, break and leak fluid. In some cases, dozens of new, abnormal blood vessels grow, a condition called proliferative retinopathy. The abnormal vessels are very fragile and break open easily. These processes gradually damage the retina, causing blurred vision, blind spots or ultimately blindness if left untreated.

Cataracts

Age is not kind to our eyes. Most people over 65 in the UK have some degree of cataracts or clouding of the lens, sufficient to interfere with vision. Vision gradually gets foggy and makes it harder to read, drive and see at night. Diabetes, smoking or prolonged sunlight exposure may increase the risk. Surgery that replaces the clouded lens with an artificial lens is highly effective.

Cataracts: What happens

In good health, the lens focuses light into a sharp, clear image on the retina, which captures the image like film in a camera. As we age, protein builds up in the lens, clouding it and sending scattered rays of light to the retina, instead of one sharp clear image. The result can be blurred vision, changes in colour vision, and glare, especially at night. Advanced cataracts are visible to the naked eye - the muddy-coloured circle at the centre of this picture.

Retinitis pigmentosa

Retinitis pigmentosa (RP) is an inherited disorder that often begins with night vision problems, followed by a gradual loss of side vision, developing into tunnel vision, and finally, in some cases, blindness. RP affects approximately one in 3,000 to 4,000 people in the UK. There is no cure yet for retinitis pigmentosa, but treatments may slow its progression. Researchers are working to develop treatments for RP and other inherited retinal diseases.

Retinitis pigmentosa (RP): What happens

The light-sensitive tissue of the retina slowly deteriorates over many years in people with RP. As this tissue dies, it stops sending signals to the brain, and some vision is lost. Eye tests show abnormal dark spots sprinkled around the retina, so-called bone spicule pigment deposits due to their shape. Early cataracts can also occur, as well as a swelling of the retina called macular oedema (the central orange mass seen here).

Floaters and specks

Blurry spots or specks that move may be floaters - debris in the eye's vitreous gel. They don't block vision and are more easily seen in bright light. Floaters are common and usually harmless, but if they change or increase suddenly, or are accompanied by light flashes or any loss of vision, you should seek medical advice or visit your optometrist urgently. These symptoms require immediate evaluation as they may indicate damage to the retina.

Lazy eye (ambylopia)

Ambylopia, or lazy eye, may stem from a misalignment of the eyes (strabismus or crossed eyes) or poorer vision in one eye. Lazy eye affects around 2% of children in the UK. When vision is reduced in one eye, the brain sometimes favours the other eye. A patch or drops that blur the vision in the "good" eye can force the brain to use the other eye. If untreated, amblyopia can lead to a permanent problem with central vision in the affected eye.

Eye care: Object in the eye

Many nerve endings lurk just beneath the surface or your cornea, so a tiny speck can be surprisingly painful. Don't rub the eye, or you may cause serious damage. Gently flushing the eye with lukewarm water is often recommended. If it doesn't dislodge the foreign body, or irritation persists, seek medical advice or visit an optometrist. Objects can be removed and antibiotic drops given to protect the cornea from infection. Seek urgent attention if the particle could have hit the eye at speed, such as debris from grinding or hammering, or if your vision is affected.

Eye care: Tears and dry eye

Tears are the lubrication for our eyes. When not enough flow, perhaps due to dry air, ageing or other health conditions, the eyes can become painful and itchy. Eye drops called artificial tears may help, but some people will need other medication or a procedure to plug the tear drainage ducts.

Eye Care: Conjunctivitis

Conjunctivitis is an inflammation caused by a virus, bacteria, irritant or allergy. Along with the tell-tale redness, you might have an itching or burning sensation and a discharge. Most infectious cases are viral, which don't require antibiotics. Bacterial conjunctivitis may be treated with antibiotic eye drops in some circumstances. Both types are very contagious, so wash your hands frequently and don't share towels or flannels while you wait for it to clear up.

Eye care: Stye

A stye is a red bump that looks like a pimple on the edge of the eyelid. It is just one type of infection of the eyelids. Styes usually heal in a week, but using a warm, wet compress three to six times a day can speed the healing. Don’t wear contact lenses or eye make-up until it heals.

Eye care: Allergies

One in three people in the UK suffers from an allergy at some time. Watery, itchy eyes are commonly triggered by allergens such as pollen, dust, weeds and pet fur. Reduce allergen levels in your home and avoid allergens as best as possible. Allergy eye drops, artificial tears and antihistamines may also soothe the symptoms.

Eye care: Regular eye tests

Everyone should have regular eye tests as often as advised by their optometrist or doctor. This is especially important if there is a family history of eye problems or you have diabetes. Beyond vision issues, the eyes can reveal underlying health problems, such as diabetes and high blood pressure. In people with high cholesterol, particles that could lodge in the retina and threaten sight may be detected. Abnormalities in an eye test can also help reveal a stroke, brain tumour or other serious disorder. Bulging eyes can be a sign of thyroid disease, and a yellow tint of the sclera (white of the eye) may indicate liver problems.

Eye protection: Sun

UV rays can damage your eyes, just as they do your skin. Regular overexposure to sun can cause cataracts 8 to 10 years earlier than normal, and a single lengthy exposure can actually burn your corneas. The solution is sunglasses that block UV rays and a hat. People with light-coloured eyes are likely to have a greater sensitivity to light. More significant light sensitivity - getting headaches or nausea from light exposure - could be a symptom of other eye disorders.

Eye protection: Everyday hazards

Grease splatters from a frying pan, garden debris flies up from the lawn mower, cleaning solution splashes in a bucket. Some of the greatest hazards to the eyes are in the home, so consider using eye protection for some DIY tasks. Even if an eye injury seems minor, seek medical advice immediately.

Foods for eye health

Carrots can be really good for your eyes. So are spinach, nuts, oranges, beef, fish, whole grains and many other foods in a healthy diet. Look for foods with omega-3 fatty acids; antioxidants such as vitamins C, E, beta-carotene and zinc, and lutein and zeaxanthin, found in spinach, kale and egg yolks. Research suggests those nutrients may reduce the risk of age-related macular degeneration.

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