Tag Archives: eyesight

Music helps stroke victims – new study

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London: Patients who have lost part of their visual awareness following a stroke can show an improved ability to see when they are listening to music they like, according to a new study published today in the journal Proceedings of the National Academy of Sciences.

Every year, an estimated 150,000 people in the UK have a stroke. Up to 60% of stroke patients have impaired visual awareness of the outside world as a result, where they have trouble interacting with certain objects in the visual world.

This impaired visual awareness, known as ‘visual neglect’, is due to the damage that a stroke causes in brain areas that are critical for the integration of vision, attention and action. Visual neglect causes the patient to lose awareness of objects in the opposite side of space compared to the site of their brain injury.

If the stroke occurs in the right hemisphere of the brain, these patients tend to lose awareness of visual information in the left side of space. This occurs even though the area of the brain associated with sight is not damaged.

The researchers behind the study, from Imperial College London, the University of Birmingham and other institutions, suggest that listening to their favourite music may help stroke patients with impaired visual awareness to regain their ability to see.

The new study looked at three patients who had lost awareness of half of their field of vision as a result of a stroke. The patients completed tasks under three conditions: while listening to their preferred music, while listening to music they did not like and in silence. All three patients could identify coloured shapes and red lights in their depleted side of vision much more accurately while they were listening to their preferred music, compared with listening to music they did not like or silence.

For example, in one task, patients were asked to press a button when they could see a red light appear. One patient could point out the light in 65% of cases while he was listening to music he liked, but could only recognise the light in 15% of cases when there was no music or music he did not like being played.

The researchers believe that the improvement in visual awareness seen in these patients could be as a result of patients experiencing positive emotions when listening to music that they like. The team suggest that when a patient experiences positive emotions this may result in more efficient signalling in the brain. This may then improve the patient’s awareness by giving the brain more resources to process stimuli.

The team also used functional MRI scans to look at the way the brain functioned while the patients performed different tasks. They found that listening to pleasant music as the patients performed the visual tasks activated the brain in areas linked to positive emotional responses to stimuli. When the brain was activated in this way, the activation in emotion brain regions was coupled with the improvement of the patients’ awareness of the visual world.

Dr David Soto, the lead author of the study from the Division of Neurosciences and Mental Health at Imperial College London, said: “Visual neglect can be a very distressing condition for stroke patients. It has a big effect on their day-to-day lives. For example, in extreme cases, patients with visual neglect may eat only the food on the right side of their plate, or shave only half of their face, thus failing to react to certain objects in the environment”.

“We wanted to see if music would improve visual awareness in these patients by influencing the individual’s emotional state. Our results are very promising, although we would like to look at a much larger group of patients with visual neglect and with other neuropsychological impairments. Our findings suggest that we should think more carefully about the individual emotional factors in patients with visual neglect and in other neurological patients following a stroke. Music appears to improve awareness because of its positive emotional effect on the patient, so similar beneficial effects may also be gained by making the patient happy in other ways. This is something we are keen to investigate further,” added Dr Soto.

This research was funded by the British Academy, Biotechnology and Biological Sciences Research Council, Economic and Social Research Council, Medical Research Council and Stroke Association.

1. About Imperial College London

Consistently rated amongst the world’s best universities, Imperial College London is a science-based institution with a reputation for excellence in teaching and research that attracts 13,000 students and 6,000 staff of the highest international quality.

Innovative research at the College explores the interface between science, medicine, engineering and business, delivering practical solutions that improve quality of life and the environment – underpinned by a dynamic enterprise culture.

Since its foundation in 1907, Imperial’s contributions to society have included the discovery of penicillin, the development of holography and the foundations of fibre optics. This commitment to the application of research for the benefit of all continues today, with current focuses including interdisciplinary collaborations to improve health in the UK and globally, tackle climate change and develop clean and sustainable sources of energy.

Website: www.imperial.ac.uk

Thousands have glaucoma without knowing, say experts

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London: Glaucoma affects up to half a million people in the UK and is the second largest cause of unnecessary sight loss.[1]

Around a quarter of a million people don’t know they have the condition as glaucoma often doesn’t have any symptoms in its early stages.[1] Boots Opticians urges you to have regular sight tests, which are crucial to help detect early signs of the disease.

Don’t wait until it’s too late. To book an eye test at Boots Opticians, call 0845 120 4343 or visit www.bootsopticians.com

Carolyn Zweig, Boots Opticians says: ‘Regular eye tests are a vital health check, which not only test your sight, but they can also detect eye conditions such as glaucoma and age-related macular degeneration, before you notice the effect on your sight. How often you have an eye test depends on your age and the recommendation of your optometrist, but as a general rule, children should be taken for an eye examination by the age of five and eye tests should be taken every two years after that until the age of 70. At 70 and beyond, you should have an eye test every year.’

Facts about glaucoma

The first World Glaucoma Day was March 6th 2008
There are four types of glaucoma – the most common is open angle or chronic glaucoma

Chronic glaucoma causes gradual blockage of the eye’s drainage tubes leading to a build-up of pressure which damages the optic nerves
50 per cent of glaucoma sufferers go undiagnosed in developed countries[2]
Up to 95 per cent of glaucoma sufferers go undiagnosed in the developing world [2]
Around two in every 100 people over 40 in the UK have glaucoma [3] which equates to approximately 600,000 people

[1] RNIB.org.uk

[2] World Glaucoma Association

3 NHS
4 Based on figures from The Office of National Statistics
5 The College Of Optometrists

Ageing eyes may get protection from antioxidants

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London: Eating foods rich in antioxidants may protect ageing eyes from degeneration, according to new research.

Scientists have found a link between two processes in the retina that, in combination, contribute to a disease called macular degeneration.

They found antioxidants disrupt the link and extend the lifetime of irreplaceable photoreceptors and other retinal cells.

“The implication is that people at risk of macular degeneration could help prevent the disease by consuming antioxidants,” said Heidi Vollmer-Snarr, a Brigham Young University chemist who earned a doctorate from Oxford and began work on this disease as a postdoctoral researcher at Columbia.

People struck with the disease first lose central vision and temporarily adjust by relying more on peripheral vision. Some eventually lose their vision entirely.

The study found a destructive synergy between the build-up of a compound called A2E and damage to cellular ‘power plants’ called mitochondria. A2E is a natural byproduct of cellular activity that, unlike other compounds, won’t break down or be disposed by the body.

A problem occurs when A2E encounters oxidative stress created by light exposure. In these circumstances, A2E disrupts energy production in mitochondria.

The resulting energy shortage pulls the plug on daily cleaning and maintenance of photoreceptors and another type of retinal cell.

The result is more A2E buildup, and the cycle of destruction hastens the death of these vital visual cells, which are not replaced when they die.

The experiments performed with visual cells from rats, cows and humans showed that antioxidants could completely counter the damage.

Seeing this process play out in the retina has given Vollmer-Snarr a novel idea for attacking harmful growths in the body.

The strategy would involve delivering potentially disruptive compounds like A2E to the target and then using light to trigger the damage.

The study appears online and is published in an issue of the Journal of Biological Chemistry.

Antioxidants do not prevent degenerative eye disease

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Melbourne: A diet rich in antioxidant vitamins and minerals does not seem to prevent the degenerative eye disease known as age related macular published on www.bmj.com today.

Age related macular degeneration is the leading cause of visual loss in older people. It is caused by the progressive break down of light sensitive cells in the macula, located in the centre of the retina at the back of the eye. Sufferers do not go blind, but find it virtually impossible to read, drive, or do tasks requiring fine, sharp, central vision.

Risk increases with age and smokers are thought to be more susceptible.

Antioxidants (such as vitamin C, vitamin E, various types of carotenoids, and zinc) are thought to reduce oxidative damage to the retina. But the evidence to support the role of dietary antioxidants in preventing macular degeneration remains unclear.

So researchers at the Centre for Eye Research Australia, the University of Melbourne analysed the evidence to examine the role of dietary antioxidants or dietary supplements in the primary prevention of age related macular degeneration.

They identified 11 studies (seven prospective studies and three randomised controlled trials) involving 149,203 people. A range of common dietary antioxidants were investigated and all the studies were carried out amongst well nourished Western populations with an average follow-up period of nine years.

Importantly, all the studies adjusted for age and smoking in their analyses.

The antioxidants investigated differed across studies, but when results were pooled they showed that vitamin A, vitamin C, vitamin E, zinc, lutein, zeaxanthin, α- carotene, β-carotene, β-cryptoxanthin and lycopene have little or no effect in the primary prevention of early age-related macular degeneration.

None of the three trials found antioxidant supplements to be protective in the primary prevention of early age related macular degeneration.

Despite some study limitations, the authors conclude that there is insufficient evidence to support the role of dietary antioxidants, including the use of dietary antioxidant supplements, for the primary prevention of early age-related macular degeneration.

Currently, cigarette smoking remains the only widely accepted modifiable risk factor for the primary prevention of early age-related macular degeneration, and patients seeking advice on this condition should be encouraged to quit, they add.

An accompanying editorial by Jennifer Evans at the International Centre for Eye Health supports these findings and says that reducing the prevalence of smoking is probably the most effective method of reducing the population burden of this common cause of visual loss in older people.

Exercise may protect eyes from ageing

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New York: Taking regular exercise may help reduce the risk of age-related eye diseases, scientists at the University of Wisconsin have discovered.

The researchers examined 4,000 men and women over a 15 years period, carrying out eye tests and recording levels of exercise, says their report in the British Journal of Ophthalmology.

Age-related macular degeneration (AMD) destroys the functionality of light sensitive cells behind the eye. The scientists found those with an active lifestyle were 70% less likely to develop the degenerative eye disease than those with a sedentary lifestyle.

AMD s the leading cause of severe vision loss in the over-50s in the developed world and affects central vision, needed for driving. The study of people aged between 43 and 86 began in 1988 and they were assessed every five years.

The research examined their exercise habits and eye health and found one in four had an active lifestyle and nearly one in four climbed more than six flights of stairs a day.

After taking into account other risk factors such as weight, blood fat levels and age, active participants were 70% less likely to develop AMD than those who did little exercise. It also showed regular walkers were 30% less likely to get the disease.

Authors of the report did warn however that diet may also explain the findings.

Stem cells may cure age-related sight loss

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WORCESTER, Mass: US scientists have used stem cells to slow vision loss in rats suffering from a similar disease to macular degeneration, says a report in the journal Cloning and Stem Cells.

The finding supports the idea of trying the technique in humans suffering from macular degeneration — the leading cause of blindness in people older than 55, The Washington Post reported.

Raymond Lund, then at the University of Utah, and Dr. Robert Lanza of Advanced Cell Technology Inc. in Worcester, Mass., started by developing a method of turning embryonic stem cells into retinal pigment epithelium cells, which nourish the eye’s light-sensitive “photoreceptor” cells, the newspaper said. In macular degeneration, the pigment cells gradually disappear.

The researchers said they succeeded in all 18 stem cell lines they worked with, injecting the stem cells, about 20,000 per eye, into the retinas of 14 rats with a genetic disease similar to macular degeneration. Eight control rats received eye injections without any cells.

The scientists found treated rats were twice as responsive as untreated ones, which started to become blind. The study also showed treated rats had twice the visual acuity of untreated rats nearly three months after treatment.

Eyesight deterioration in elderly may be linked to diet

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Boston: The leading cause of blindness in the elderly, age-related macular degeneration (AMD), may be accelerated by regular diet of “high glycemic index” foods.

People with AMD are also likely to suffer from other health problems such as cognitive impairment, or problems with thinking, learning and memory, according to a new study in the April issue of the Archives of Ophthalmology.

The study was led by Chung-Jung Chiu and Allen Taylor at the Jean Mayer USDA Human Nutrition Research Center on Aging in Boston, Mass., and is part of the Nutrition and Vision Project, a substudy of the federally funded Nurses’ Health Study.

A high glycemic-index diet is a diet high in the type of carbohydrates that are quickly digested and absorbed, resulting in a rapid rise in blood glucose levels. The macula is a yellow pigmented spot, one-eighth-inch wide, in the center of the retina toward the back of the eye. AMD is one of the leading causes of irreversible vision loss among those aged 40 or older in the United States.

Study participants were 526 women aged 53 to 73 years who did not have a history of age-related maculopathy, the early form of AMD. The scientists assessed the participants for macular disease and classified the results. They then compared the results with long-term dietary information that had been collected using questionnaires over a 10-year period prior to the macular disease assessment.

When ranked into three groups from highest to lowest in terms of dietary glycemic index, the participants who were ranked highest were well over two times more likely to have macular pigment abnormalities as those ranked lowest.

An abnormal level of macular pigment is an early indicator of macular degeneration. The macula is responsible for the maximum ability to receive light and distinguish images.

Although the data do not establish a causal relationship, they do indicate a new direction for further studies that may help prevent or delay the onset of macular disease.