After blindness, the adult brain can learn to see again

More than 40 million people worldwide are blind, and many of them reach this condition after many years of slow and progressive retinal degeneration. The development of sophisticated prostheses or new light-responsive elements, aiming to replace the disrupted retinal function and to feed restored visual signals to the brain, has provided new hope. However, very little is known about whether the brain of blind people retains residual capacity to process restored or artificial visual inputs. A new study published in the open-access journal PLOS Biology by Elisa Castaldi and Maria Concetta Morrone from the University of Pisa, Italy, and colleagues investigates the brain’s capability to process visual information after many years of total blindness, by studying patients affected by Retinitis Pigmentosa, a hereditary illness of the retina that gradually leads to complete blindness.

Fundus of the patient’s eye implanted with Argus II Retinal 98 Prosthesis, taken soon after the surgery Image Credit: Castaldi E, Cicchini GM, Cinelli L, Biagi L, Rizzo S, Morrone MC (2016)

 

The perceptual and brain responses of a group of patients were assessed before and after the implantation of a prosthetic implant that senses visual signals and transmits them to the brain by stimulating axons of retinal ganglion cells. Using functional magnetic resonance imaging, the researchers found that patients learned to recognize unusual visual stimuli, such as flashes of light, and that this ability correlated with increased brain activity. However, this change in brain activity, observed at both the thalamic and cortical level, took extensive training over a long period of time to become established: the more the patient practiced, the more their brain responded to visual stimuli, and the better they perceived the visual stimuli using the implant. In other words, the brain needs to learn to see again.

The results are important as they show that after the implantation of a prosthetic device the brain undergoes plastic changes to re-learn how to make use of the new artificial and probably aberrant visual signals. They demonstrate a residual plasticity of the sensory circuitry of the adult brain after many years of deprivation, which can be exploited in the development of new prosthetic implants.

Article: Visual BOLD Response in Late Blind Subjects with Argus II Retinal Prosthesis, Castaldi E, Cicchini GM, Cinelli L, Biagi L, Rizzo S, Morrone MC, PLOS Biology, doi:10.1371/journal.pbio.1002569,


Level of education is more decisive than intelligence for the development of short-sightedness

Environmental factors such as education and leisure activities have a greater influence on the development of short-sightedness or myopia than the ability to think logically and solve problems. Myopia and the so-called “fluid intelligence” of a person are certainly related, but only indirectly through the duration of education. This is the conclusion of researchers at the Mainz University Medical Center involved in the study “Myopia and Cognitive Performance: Results from the Gutenberg Health Study.” The results of the study appeared in the October issue of the specialist journal Investigative Ophthalmology & Visual Science.

Myopia, also known as short-sightedness or near-sightedness, is the most common disorder affecting the eyesight and the condition is on the increase. Severe short-sightedness is one of the main causes of impaired vision. In addition, it is closely associated with an increased risk of secondary complications such as retinal detachmentmacular degeneration, premature cataracts, and glaucoma. Because myopia can be easily treated in the early stages, although it cannot be fully cured, insight into the causes of the disease is of central importance.

“We know from earlier studies that a higher level of education frequently goes hand-in-hand with the development of short-sightedness,” said Professor Norbert Pfeiffer, Director of the Department of Ophthalmology at the University Medical Center of Johannes Gutenberg University Mainz (JGU). Together with Professor Alireza Mirshahi, Director of the Bonn Dardenne Eye Clinic, and Professor Josef Unterrainer, who heads the Department of Medical Psychology and Medical Sociology at the University of Freiburg, Pfeiffer was in charge of the study “Myopia and Cognitive Performance: Results From the Gutenberg Health Study,” which was the subject of the recent publication. The core question being considered is whether short-sighted people are not only better educated but also more intelligent.

Based on their findings, the research team lead by Pfeiffer, Mirshahi, and Unterrainer have come to the following conclusions: Considered in isolation, cognitive ability and, thus, intelligence apparently plays a significant role in the development of short-sightedness. But when the researchers took into account already identified potential influencing factors, they discovered that the number of years over which an individual received education exhibited a more direct and closer relationship with short-sightedness than cognitive ability. This means that it is only through educational attainments that cognitive ability is linked to myopia. In other words, the level of education rather than intelligence is more decisive for development of short-sightedness. In the case of two equally intelligent people, it is thus most probably the one who attended school for longer and has the better educational qualifications who will become myopic and experience more defective vision.

For their study, the research team analyzed data collected within the framework of the Gutenberg Health Study conducted by the Mainz University Medical Center. This is one of the largest population-based research studies in the world. The sub-cohort consisted of some 4,000 subjects aged 40 to 79 years. The researchers used the Tower of London (TOL) test to measure cognitive functioning. The 20-minute test assesses cognitive ability by mentally planning ahead and problem solving. In order to diagnose myopia, the researchers examined the refractive power of the eyes of subjects, thus determining how much their eyes had to adjust to produce a sharp image. Short-sightedness is characterized by negative diopter values. In the study, myopia was diagnosed when the identified diopter value was less than or equal to 0.5.


Eye health: Our top tips for healthy eyes

Eye health

Our top tips for healthy eyes

  • Have regular check-ups

Have your eyes tested every two years even if you think your vision is fine. An eye test can spot some eye conditions and other illnesses not related to sight. Regular check-ups are vital even if you have no symptoms.

  • Find out your family eye health history

Talk to your relatives about your family eye health history. Some eye conditions have genetic links which increase your risk of developing them. Share this information with your optometrist or eye health professional.

  • Take care of your contact lenses

If you wear contact lenses make sure you look after them properly. Thoroughly wash and dry your hands before touching your contact lenses or your eyes. Your lenses and their case should only ever be cleaned with the lens solution recommended by your optometrist. Always follow the instructions given to you by your optometrist or the lens manufacturer.

  • Wear sunglasses

Protect your eyes when it is sunny or when you’re in high glare areas such as near snow or water. The CE or BS EN 1836:2005 marks indicate that sunglasses provide a safe level of protection from the sun’s damaging UVA and UVB rays. Ongoing UV exposure can increase your risk of developing cataracts or macular degeneration.

  • Protect your eyes

Wear safety glasses or protective goggles to protect your eyes from injury if you work with hazardous or airborne materials. This applies to home too if you are doing DIY, gardening or setting off fireworks.

  • Keep fit and healthy

Being fit and well can help your eyes stay healthy. Maintaining a healthy weight and blood pressure may help with eye health. Protect your eyes when playing sports involving flying balls.

  • Eat well

Make sure your diet includes nutrients such as Omega 3 fatty acids, zinc and vitamins C and E. These may help to prevent or delay age-related vision problems such as macular degeneration and cataracts. Recommended foods for general good health include green leafy vegetables, oily fish such as salmon and citrus fruits.

  • Stop smoking

Smoking is harmful to your eyes and can increase the risk of sight loss. Current smokers are 2-4 times more at risk of developing macular degeneration than people who have never smoked.

  • Avoid recreational drugs

There is evidence to suggest that some recreational drugs can cause sight loss – particularly alkyl nitrites, also known as poppers.

 

Facts about sight loss

  • Every 5 seconds someone in the world goes blind
  • Every day 100 people in the UK start to lose their sight
  • Almost 2 million people in the UK are living with significant sight loss. The number is predicted to rise to around 2.3 million by 2020 and almost 4 million by 2050
  • Around 360,000 people in the UK are registered blind or partially sighted
  • An estimated 25,000 children in Britain are blind or partially sighted
  • 86% of people in the UK value their sight above any other sense
  • Sight loss can affect people of any age but the likelihood increases as you get older: One in five people over 70 are living with sight loss
  • Black and Asian people are at greater risk of developing certain conditions which can result in the onset of some of the leading causes of sight loss

 


Retinal Migraine: Causes, Symptoms, and Treatment

A retinal migraine is one of many types of migraine. A retinal migraine is rare, and it is different from a migraine headache or a migraine with aura. Those conditions usually affect the vision in both eyes. A retinal migraine affects vision in one eye only.

Around 1 in every 200 people who get migraines will have a retinal migraine.

The condition is also sometimes called an ophthalmic migraine, visual migraine, or an ocular migraine, although symptoms for these are slightly different.

A retinal migraine is an eye condition. It can cause temporary blindness or visual problems in one eye. Retinal migraines usually last for up to 1 hour and are followed by the return of normal vision.

Contents of this article:

Causes of a retinal migraine

A retinal migraine is caused by a reduction in blood flow to the eye when blood vessels narrow suddenly. There are several reasons why this might happen.

A retinal migraine starts with visual disturbances in one eye.

 

Factors that might trigger blood vessel narrowing and retinal migraines include:

As the blood vessels relax and blood flow returns to normal, the symptoms usually disappear and vision comes back.

Some people are more at risk of a retinal migraine than others. These people include:

  • People aged 40 years and under
  • Individuals with a family history of migraines
  • People with another condition, such as atherosclerosisepilepsylupus, and sickle cell disease

It affects women more often than men.

Symptoms

Retinal migraines involve repeated attacks of certain visual disturbances. These usually happen before the headache phase of a migraine. The visual disturbances are often collectively referred to as “aura.”

Symptoms occur in one eye. The characteristics of an aura may include:

  • Seeing flashing, sparkling, or twinkling lights
  • A blind spot or partial loss of vision
  • Temporary blindness

The aura may spread gradually over 5 minutes or more and last for 6-60 minutes. Within 60 minutes of visual symptoms, the headache phase of a retinal migraine may begin.

The headache phase of a retinal migraine has symptoms like a migraine without aura. These symptoms include a headache that lasts 4 to 72 hours on one side of the head.

The headache may be:

  • Pulsing or throbbing
  • Moderate to severe in pain intensity
  • Made worse by activities such as walking or climbing stairs

A migraine headache may also cause:

  • Nausea and vomiting
  • Increased sensitivity to light
  • Increased sensitivity to sound

A migraine with aura is a different condition to a retinal migraine, although some of the symptoms are similar.

Migraines with aura also cause visual disturbances such as flashes of light, blind spots, and other visual changes. However, a retinal migraine differs from a migraine with aura for two main reasons:

  • The visual symptoms only occur in one eye and not both
  • Complete but temporary blindness may occur in one eye only

Diagnosis

There are no diagnostic tests that detect a retinal migraine. A doctor may diagnose a retinal migraine by examining personal and family medical history, asking about symptoms, and conducting an examination.

Other possible causes for the symptoms will be ruled out before a retinal migraine is diagnosed. It is important to investigate and rule out other causes of temporary blindness.

A specialist doctor might need to ensure that the symptoms are not caused by a serious eye disease or stroke.

Some people that have visual disturbances in one eye might have hemianopia. Hemianopia is the loss of vision on the same side in both eyes. This condition often happens in stroke and traumatic brain injuries.

Treatments

The medication that a doctor prescribes to treat retinal migraines may change depending on a person’s age and how frequently they have retinal migraine attacks.

Prescribed medication might include:

NSAIDS such as ibuprofen or aspirin may relieve the pain of the headache.

 

  • Non-steroidal anti-inflammatory drugs(NSAIDs), such as aspirinor ibuprofen, to relieve pain and inflammation
  • Anti nausea medications to prevent nausea and vomiting
  • Ergotamines to narrow blood vessels in the brain to relieve a headache
  • Triptans to narrow blood vessels in the brain and reduce swelling
  • Beta-blockersto relax blood vessels in the brain
  • Calciumchannel blockers to prevent blood vessels constricting
  • Antidepressantsto help prevent a migraine
  • Anticonvulsants to help prevent a migraine

There is currently a lack of research into the best way to treat a retinal migraine. However, most treatments focus on pain relief for headaches and reducing exposure to potential retinal migraine triggers.

Complications

There is a small risk with a retinal migraine that the sudden reduction in blood flow to the eye may damage the retina and blood vessels of the eye.

The medications that are used to treat a retinal migraine can sometimes cause other problems.

  • NSAIDs may cause stomach pain, bleeding, ulcers, and other problems
  • Medications can cause overuse headaches if an individual uses them for more than 10 days a month for 3 months
  • Serotoninsyndrome is a rare, life-threatening condition that has an increased risk in people that combine certain antidepressants and triptans

The permanent loss of vision following a retinal migraine is rare.


Researchers find children with ‘wobbly eye’ unable to recognise faces

Researchers in Southampton have discovered children who suffer from eye movement disorder nystagmus – known as ‘wobbly eye’ – struggle to recognise faces but not other objects.

It is hoped the novel finding, which was made following a study led by consultant paediatric ophthalmologist Jay Self and his team at Southampton Children’s Hospital, will lead to the development of more accurate diagnostic tests and better support for patients.

Nystagmus causes the eyes to ‘wobble’ and creates strobe vision, which makes it difficult to see moving objects, recognise familiar faces or perform everyday activities such as playing with toys and friends.

Although the condition, which affects around one in 1,500 people in the UK, can develop in later life, it is more commonly found in babies and young children – known as congenital nystagmus – and can be caused by many different underlying conditions.

The study, carried out by medical student Shinn Tan, in collaboration with the psychology team at the University of Southampton and clinicians in Cardiff and Plymouth, compared how children with and without nystagmus look at faces using an innovative infrared eye-tracking device.

Children were shown two different images on a computer screen at the same time while the Eyelink 1000 Plus analyser used infrared light reflected from the cornea of their eye to measure the time spent looking at each image.

When presented with a black and white checkerboard pattern and a plain grey panel, all children spent longer looking at the distinctive checkerboard and seemed to identify it very quickly – as expected by the clinicians.

However, when shown photos of their own mother’s face and that of another woman, children without nystagmus spent longer looking at their mother and found their face very quickly, while those with the condition looked at both faces for the same length of time and seemed to struggle to identify their own mother’s face.

“Nystagmus is an extremely complicated condition, therefore, testing and diagnosing it has proved very challenging, so we are constantly looking for ways to improve and enhance methods of diagnosis, as well as increase the support available to patients,” explained Mr Self, who is associate professor of ophthalmology at the University of Southampton.

“These results indicate that children with nystagmus may have specific difficulty recognising faces or adopt different ways of looking at faces – something that’s rarely detected by standard eye tests.”

He added: “The findings could provide the basis of a more accurate diagnosis of nystagmus severity and measure of the efficacy of trial treatments, as well as improved social support and understanding for patients.”

The study was funded by the Nystagmus Network.


Sunglasses for children

Children may not be interested in the fashion aspect of sunglasses, but given that kids spend much more time outdoors than most adults, sunglasses that block 100 percent of the sun’s harmful ultraviolet (UV) rays are an important consideration.

In fact, according to some experts, up to half of a person’s lifetime exposure to UV radiation can occur by age 18. (Other research cited by The Skin Cancer Foundation suggests the amount of lifetime exposure to UV radiation sustained by age 18 is less than 25 percent.)


Sunglasses help protect children’s eyes from UV rays and glare, whether it’s a sunny day at the beach or a cloudy day on a snowy mountaintop. Make sure your child’s sunglass lenses are made of a shatter-resistant material such as polycarbonate.

 

Given that excessive lifetime exposure to UV radiation has been linked to the development of cataracts and other eye problems, it’s never too early for kids to begin wearing good quality sunglasses outdoors.

UV rays aren’t the only potential danger from sunlight. Recently, researchers have suggested that long-term exposure to high-energy visible (HEV) light rays, also called “blue light,” may also cause eye damage over time. In particular, some believe a high lifetime exposure to HEV light may contribute to the development of macular degeneration later in life.

Children’s eyes are more susceptible to UV and HEV radiation than adult eyes because the lens inside a child’s eye is less capable of filtering these high-energy rays. This is especially true for young children, so it’s wise for kids to start wearing protective sunglasses outdoors as early in life as possible.

It is also important to consider that your child’s exposure to UV rays increases at high altitudes, in tropical regions and in highly reflective environments (such as in a snowfield, on the water or on a sandy beach). Protective sun wear is especially important for kids in these situations.

Choosing sunglass lens colours

The level of UV protection that sunglasses provide is not related to the colour of the lenses.

As long as your optician certifies that the lenses block 100 percent of the sun’s UV rays, the choice of colour and tint density is a matter of personal preference.

Most sunglass lenses that block the sun’s HEV rays are amber or copper in colour. By blocking blue light, these lenses also enhance contrast, a positive feature for outdoor sports and cycling.

Sunglass styles for children

Colourful, adolescent frame styles are still available, but sunglass companies have found a niche in appealing to children’s desire to look like their parents or older siblings.

Oval, round, rectangular, cat-eye and geometric shapes are all popular in cool, sophisticated colours like green, blue, tortoise and black. Metal frames are very popular, but so are plastic sunglass frames that look like scaled-down versions of trendy adult styles. Also, sporty styles for kids like wraparounds are available in miniature adult editions.

Where to buy kids’ sunglasses

The best places to find kids’ sunglasses or obtain advice regarding them, are sunglass specialty stores like your local optician or optical shop.

Some opticians even specialise in children’s sunglasses and eyeglasses and have dedicated areas just for kids to play and shop for their frames.

Wherever you go, look for a good selection of sunglass frames scaled specifically for a child’s facial dimensions and a professional staff experienced in fitting children’s eyewear.

 


Blurry Vision and Diabetes what’s the connection

Blurry vision is being unable to see the fine details.

Blurred vision can be described as the lack of clarity or detail when viewing an object, similar to seeing things as if they are out-of-focus in a photograph.

The blurriness can be subtle or obvious, can change through the day, and can come on slowly or quickly. It depends on the cause.

Diabetes can cause blurry vision for a variety of reasons. Both short-term and long-term complications can affect the vision of someone with diabetes.

Contents of this article:

How does diabetes affect the eyes?

Long-term uncontrolled diabetes can lead to high blood sugar levels that cause damage to small blood vessels over time. This damage can lead to problems with part of the eye called the retina which can create blurred vision.

There are many reasons why diabetes might cause blurry vision.

Short-term blurriness in people with diabetes is due to a different cause. Fluid shifts into and out of the eye due to high blood sugar levels, causing the lens of the eye to swell.

This change in its shape causes blurriness as the lens is the part that focuses light onto the back of the eye. This short-term issue will resolve once blood sugar levels are lowered.

Can diabetes treatment cause blurriness?

Diabetes can also cause short-term blurriness if blood sugar levels fall too low (hypoglycemia). This can happen due to the timing of food or a change in activity levels in people who take medication that increases insulin in the body.

Rather than being caused by changes in the eye, blurriness from low blood sugars is caused by the effects of hypoglycemia on the brain. Vision affected in this way will return to normal after glucose levels return to normal.

Is blurry vision with diabetes temporary?

As stated above, blurry vision can be caused by both short-term and long-term complications of diabetes.

Long-term eye problems are related to blood vessel damage in the retina of one or both eyes due to high blood sugar levels over the course of many years.

These complications are not temporary, although their progression can be slowed down.

Short-term blurred vision due to high or low blood sugar levels is temporary and will resolve when blood sugar levels return to normal.

When should I see a doctor if I have blurry vision?

A range of medical conditions can cause blurry vision, and diabetes is just one.

Most people who begin to suffer with blurred vision may simply need eyesight correction with the help of an optometrist. However, anyone who develops blurry vision should see a doctor – especially if the problem has appeared suddenly.

Eye problems can be related to new cases of diabetes or can be a complication of an existing condition.

Whether diabetes has yet to be diagnosed or is already under medical care, symptoms of blurred vision should always be fully investigated.

Routine eye examinations should be carried out for all diabetic patients, at least once every year. Doing so will pick up any eye complications while they are still minor.

Regular diabetes eye checks

In addition to the annual eye examination with an optometrist, a detailed view of the retina is also necessary. This is usually carried out as part of a diabetic screening program through GP referral once the diabetes has been diagnosed. In most instances these checks are also annual, but may need to be carried out more frequently if the ophthalmologist/specialist feels that it is needed.

Diabetic screening involves the specialist looking at the back of the eye (the retina) after dilating the eye (making the pupil bigger with a drug delivered via eye drops) and is often referred to as the dilated eye exam. It enables the detection of diabetic retinopathy – disease of the retina caused by diabetes.

If diabetic eye problems are known to have developed already, multiple follow-up checks will be recommended to take place every year.

Pregnant women should also have more regular checks.

Long-term eye problems with diabetes

Eye complications caused by diabetes are progressive. They can start at a point where they are found only by a specialist eye examination, before any eye or visual symptoms appear.


Eye disease caused by diabetes gets worse over time without treatment.

Retinopathy has the potential to progress onto increasingly worse states. Broadly, there are two stages of this eye disease:

  • Background retinopathy, or non-proliferative diabetic retinopathy (NPDR) – early stages, with no symptoms, or only mild ones
  • Proliferative diabetic retinopathy (PDR) – advanced stages of eye complications

With NPDR, the retina’s tiny blood vessels may be weakened and blocked. There may be bulges in them, or fluid can leak out. This can cause swelling in the central part of the retina.

NPDR can be classed as mild, moderate, or severe based on the extent of the blood vessel problem.

Swelling in the retina is known as macula oedema. It can cause vision problems because the macula is located centrally at the back of the eye and allows fine detail to be resolved.

PDR, the more advanced stage of eye disease that can be caused by diabetes, results from blood vessel problems. Vessels fail to get blood to the retina because they have closed up, and new vessels start to grow to compensate for this. This stage only develops in some people with diabetes and takes several years to develop.

The growth of new blood vessels does not provide normal blood flow to the retina, however, and it can lead to scarring and wrinkling. If this is severe enough, vision can become distorted. The retina can even become detached, causing a loss of vision.

The fragile new vessels can also bleed out. Symptoms of this can include floating spots in the vision. If a bleed from the retina into the central part of the eye is substantial, sight can sometimes be lost, leaving only the ability to tell light from dark.

Eventually, new vessels can also start forming in the iris, the part that gives people their eye color. This affects the balance of fluid inside the eye. Glaucoma is the result – a build up of pressure in the eye that can affect the optic nerve.

Treatment of long-term eye problems with diabetes

The goal of regular eye checks for diabetic patients is to identify problems with the retina at the earliest stages. It is good news if diabetes is well-controlled and no changes to the back of the eye can be seen for a number of years.


Keeping blood sugar levels under control is important for treating eye problems caused by diabetes.

When it is found at its earliest stages, retinopathy can be managed with monitoring and controlling those things that can affect eye health, such as high blood sugar level and high blood pressure.

Preventive measures can then be started in time to slow down the condition. Otherwise, retinopathy is a progressive condition that worsens if blood sugar levels remain too high.

Problems with the retina can be prevented by bringing sugar levels under control. Keeping tight control of blood sugar levels also slows down any retinopathy that has already been found.

The diet and lifestyle measures that are needed to manage diabetes are the same measures that prevent eye problems. Any further medical help for diabetes also controls the risk for eye complications.

Good blood sugar control also helps to keep another risk factor for eye problems under control – high blood pressure (hypertension).

Preventing high blood sugar levels can have wider benefits against other diabetes complications, too. Diabetic neuropathy, which can cause loss of sensation throughout the body, is due to damage to nerves due to high blood sugar levels.

Prevention with regular checks and strict diabetes management is better than managing the complication once it occurs. But if retinopathy does reach the later stages of progression, specific eye treatments may be needed.

Eye doctors may recommend:

  • Injections in the eye
  • Laser surgery on the back of the eye – used to reduce swelling at the centre of the retina, to shrink or prevent abnormal blood vessel growth, and prevent bleeds
  • Microsurgery in the eye

How to Boost Your Diet and Nutrition to Protect Aging Eyes

Age-related eye diseases such as macular degeneration and cataracts commonly cause impaired vision and blindness in older adults. But lifestyle changes including good nutrition, could help delay or prevent certain eye problems.

Besides adopting a healthy diet, we can also protect our eyes by avoiding intense ultraviolet (UV) light, quitting smoking and having regular check-ups that may help detect chronic diseases contributing to eye problems. Diabetes for example, increases your risk for age-related eye diseases and may cause diabetic retinopathy.

Regular eye exams are essential for maintaining eye optimum health. If eye problems and chronic diseases are detected early enough, appropriate treatment may prevent permanent vision loss.

Diet, Antioxidants and Healthy Eyes

A healthy, balanced diet is an important consideration when making daily lifestyle choices. Foods we eat and the dietary supplements we take, affect both overall wellbeing and ocular health.
Eat plenty of colourful fruits and vegetables for optimum eye health.

A diet high in saturated fat and sugar may increase the risk of eye disease. On the other hand, healthy foods such as greens and fruits may help prevent certain eye diseases and other health problems.

Cardiovascular disease, diabetes and eye conditions including cataracts and age-related macular degeneration (AMD) have been shown to occur less frequently in people who eat diets rich in vitamins, minerals, healthy proteins, omega-3 fatty acids and lutein.

A healthy diet should include ample amounts of fresh, colourful fruits and vegetables. In fact, experts recommend that you consume at least five to nine servings of these foods daily.

Dark green or brightly coloured fruits and vegetables which contain antioxidants, have been shown to protect the eyes from free radical damage, thus reducing the risk of certain eye diseases.
Lutein and zeaxanthin are plant pigments called carotenoids and these are known to protect the retina from oxidative changes caused by ultraviolet light. Spinach and kale are excellent food sources of lutein and zeaxanthin.They are also found in sweet corn, peas and broccoli.

Vitamin A, vital for healthy vision, is found in orange and yellow vegetables such as carrots and squash. Fruits and vegetables also provide essential vitamin C, another powerful antioxidant.

Other Guidelines for Diet and Eye Health

Try following these diet guidelines to improve your chance of healthy vision for a lifetime:


Supplements, such as these containing essential fatty acids and vitamin E, can help maintain vision.

  1. Eat whole grains and cereals. Sugars and refined white flours commonly found in breads and cereal may increase your risk of age-related eye diseases. Choose instead 100 percent whole-grain breads and cereals that have lots of fibre. This slows down the digestion and absorption of sugars and starches. Fibre also keeps us feeling full, which makes it easier to limit the amount of calories we consume. Experts suggest that at least half of our daily grains and cereals be 100 percent whole grains.
  2. Make sure fats are healthy. The omega-3 essential fatty acids found in fish, flaxseed oil, walnuts and canola oil help to prevent dry eyes and possibly cataracts. Eat fish or seafood twice weekly, or take flax oil every day. .
  3. Choose good sources of protein. Remember that the fat content of meats and the cooking method used to prepare them contribute to making them healthy or unhealthy. Also, limit the consumption of saturated fats from red meats and dairy products as this may increase the risk of macular degeneration. Choose lean meats, fish, nuts, legumes and eggs for proteins. Most meats and seafood also are excellent sources of zinc. Eggs are a good source of lutein.
  4. Avoid sodium. High sodium intake may add to the risk of cataract formation. Use less salt, and look for sodium content on the labels of canned and packaged foods. Stay below 2,000 mg of sodium each day. Choose fresh and frozen foods whenever possible.
  5. Stay hydrated. Consider a diet with low-fat dairy products such as skimmed milk for calcium, and healthy beverages such as 100 percent vegetable juices, fruit juices, non-caffeinated herbal teas and water. Proper hydration may also reduce irritation from dry eyes.

Always wear sunglasses for protection from the sun’s harmful UV rays.

Eye Vitamins and Vision Supplements

In additional to a healthy, balanced diet and exercise, taking a daily nutritional supplement may further protect the eye from disease and age related ocular changes.

Two large, five-year clinical trials called the Age-Related Eye Disease Studies (AREDS and AREDS2) have provided valuable information about the benefits of vision supplements.

Sponsored by the National Eye Institute, AREDS and AREDS2 specifically investigated the effect of taking a daily antioxidant multivitamin on the development and progression of AMD and cataracts among adults ages 55 to 80.

The original AREDS study found that a supplement containing the following ingredients reduced the risk of advanced AMD among study participants at high risk of vision loss due to pre-existing intermediate AMD (or advanced AMD in one eye) by 25 percent:

  • beta-carotene (15 mg)
  • vitamin C (250 mg)
  • vitamin E (400 IU)
  • zinc (80 mg)

The AREDS2 study investigated whether including or substituting other nutrients in the original AREDS formulation might provide even greater eye benefits.

Specifically, AREDS2 investigated the effect of adding either a combination of lutein and zeaxanthin (10 mg and 2 mg, respectively) or omega-3 fatty acids (350 mg DHA and 650 mg EPA) to the original AREDS supplement.

AREDS2 also removed beta-carotene from the original AREDS formulation, since other studies have found too much of this vitamin A precursor, particularly when taken in supplement form, is associated with increased risk of lung cancer among smokers and previous smokers.

AREDS2 also decreased the amount of zinc — from 80 mg in the original AREDS formulation to 20 mg — to reduce the potential for stomach upset some people experience when taking the higher dose.

Results of the AREDS2 study showed that use of a daily multivitamin supplement that also contained lutein and zeaxanthin (and no beta-carotene) reduced the risk of progression of AMD to advanced stages by up to 25 percent, with the greatest risk reduction occurring among participants whose diets were low in lutein and zeaxanthin at the time of enrolment in the study.

Daily multivitamin supplements containing omega-3 fatty acids (and no lutein, zeaxanthin or beta-carotene), on the other hand, failed to show any benefit toward reducing the risk of progressive AMD.

Neither AREDS nor AREDS2 found that use of daily multivitamins — with or without lutein/zeaxanthin or omega-3 fatty acids — prevented or reduced the risk of cataracts among the study participants.

Also, the AREDS and AREDS2 supplements did not prevent or reduce the risk of AMD among study participants who had no signs of macular degeneration at the onset of the five-year studies.

Another influential and large-scale nutritional study is the Blue Mountains Eye Study. Conducted in Australia, this study found that daily multivitamins and B vitamin supplements — especially those containing folic acid and vitamin B12 — reduced the risk of cataract formation in study participants. Results also showed that daily omega-3 fatty acid supplements also reduced the risk of cataracts.

The Blue Mountains Eye Study also reported on the long-term effects of adherence to a healthy diet. The study authors found that individuals who were 65 and older and had maintained a better diet had less risk of visual impairment over a 10-year follow-up period.

Based on the results of these and other studies, and because it can be difficult to obtain the same level of nutrients investigated in these studies by diet alone, taking a daily eye supplement should be considered.

Experts suggest high-quality eye and vision supplements should contain at least the following ingredients for optimum effect:

  • vitamin C (250 to 500 mg)
  • vitamin E (400 IU)
  • zinc (25 to 40 mg)
  • copper (2 mg)
  • vitamin B complex that also contains 400 mcg of folic acid
  • omega-3 fatty acids (2,000 mg)

Taking eye vitamins and vision supplements is generally very safe, but be sure to check with your doctor first if you are on medications, are pregnant or nursing, or are considering taking higher daily doses than those listed above.


Zika: Could virus spread via contact with sweat, tears?

In a letter to the New England Journal of Medicine, doctors discuss a rare case of the death in the United States of a patient infected with Zika virus, and how another patient may have contracted the virus by coming into contact with the first patient’s sweat or tears.


The researchers discuss the possibility that Zika may spread through contact with tears of sweat from a highly infectious patient.

The first patient, a 73-year-old man, died in June of this year at the University of Utah hospital in Salt Lake City – the first known case of Zika virus-related death in the continental U.S.

He began experiencing symptoms of Zika virus infection 8 days after returning from a trip to southwest Mexico, a Zika-infected area.

At first, his symptoms were abdominal pain and fever. By the time he was admitted to the hospital, he also had watery, inflamed eyes, low blood pressure, and a rapid heart rate. He developed septic shock, his kidneys, lungs, and other organs shut down, and he died shortly after.

The second patient, “a previously healthy 38-year-old man with no known coexisting illnesses,” visited the first patient in hospital and reported wiping away his tears and helping nurses to reposition him in the hospital bed.

He came to the attention of one of the authors during a discussion about what happened to the first patient a week after he died; they noticed he had red, watery eyes, a common symptom of Zika infection.

Tests confirmed the second patient was infected with Zika, but his symptoms were only mild and resolved within a few days.

Case continues to puzzle health experts

Two aspects of this case continue to puzzle health experts. First, why did the first patient die? It is very rare for Zika infection to even cause severe illness in adults – much less, death.

Fast facts about Zika

  • Health authorities say the best way to prevent Zika is to prevent mosquito bites
  • Pregnant women are advised not to travel to areas with Zika
  • Couples with a partner who lives in or has been to a Zika area should take protective measures during sex.

Only nine other cases of deaths linked to Zika virus have been reported worldwide, note the researchers from the University of Utah School of Medicine, together with colleagues from ARUP Laboratories, also in Salt Lake City.

The second point that remains a mystery is how did the second patient contract Zika? He did nothing that was known at the time to put himself at risk.

In their letter, the researchers suggest unusually high levels of Zika virus in the first patient’s blood may have been the cause of his death.

This may also explain why the second patient may have become infected with the virus – through touching tears or sweat from the first patient. The authors note this is the first time such a transmission route has been documented.

Corresponding author Sankar Swaminathan, a professor of internal medicine at the University of Utah School of Medicine, remarks:

“This rare case is helping us to understand the full spectrum of the disease, and the precautions we may need to take to avoid passing the virus from one person to another in specific situations.”

‘Viral load 100,000 times higher’

The researchers ran several tests to show there were no other infections that could explain the first patient’s illness. One of these is called Taxonomer, which rapidly analyzes all genetic material from infectious agents in a patient’s sample.

They found the Zika virus the first patient was infected with was 99.8 percent identical to that identified in a mosquito collected from the area he had visited – southwest Mexico – in the weeks before falling ill.

In discussing how the second patient became infected, the authors note that the species of mosquito that carries Zika has not been found in Utah, he had not traveled to a Zika-infected area, and a reconstruction of events ruled out any other known means of transmission.

The researchers suggest the reason the second patient become infected was because the first patient had unusually high levels of virus in his body – 200 million particles per milliliter. This could have overwhelmed his system and made him extremely infectious.

Prof. Swaminathan, who is also chief of infectious diseases at the School of Medicine, describes his reaction:

“I couldn’t believe it. The viral load was 100,000 times higher than what had been reported in other Zika cases, and was an unusually high amount for any infection.”

The researchers say they still do not know what led to such an unusually severe infection. Did something in the first patient’s biology or health history make him particularly vulnerable? Was the particular strain he had – there were tiny genetic differences to other known strains – particularly aggressive?

Prof. Swaminathan says we may never see another case like this, and it shows we still have a lot to learn about Zika.

“This type of information could help us improve treatments for Zika as the virus continues to spread across the world and within our country.”

Prof. Sankar Swaminathan