Archive for the Eye News Category

Kilos could dim your sight

Posted in Eye News on June 12, 2008 by larrazabaleye

How much you weigh and whether you exercise could influence more than just your jean size.

It might also have a powerful impact on the progression of age-related macular degeneration, a disease affecting some thousands of South Africans and a major cause of blindness among seniors, reports a study in the June issue of the Archives of Ophthalmology.

Why research is unique and important
What makes this research unique is that it involved evaluation of the progression of this disease, and a documentation that certain factors – most notably body mass index and exercise – can play a role in how quickly that progression occurs, says study author Dr Johanna Seddon, of the Massachusetts Eye and Ear Infirmary.

The idea that these factors could be modified and controlled makes the finding that much more meaningful and important to patients, Seddon adds.

Age-related macular degeneration (AMD) develops when the high concentration of light-sensing cells in the central portion of the retina – the area known as the macula – malfunction or begin to lose function. Initially, this causes a decrease in central vision and the inability to see fine detail. Eventually, it destroys sight, plunging some 40 000 South African seniors into total blindness each year.

Different theories to explain correlation
While doctors aren’t certain why weight and exercise make a difference, Seddon believes it may influence inflammation in the tiny blood vessels that remove waste products from the retina.

Right now we know that some of the same risk factors for heart disease – smoking, obesity and lack of exercise – also affect the progression of AMD, Seddon says.

For ophthalmologist Dr Robert Cykiert, the study is an important step forward for patients with this devastating disease.

Because AMD has no known cure, slowing down the progression is the only tool that patients have to preserve their eyesight. So, obviously, anything that can help accomplish this is vital, says Cykiert, a clinical associate professor of ophthalmology at New York University Medical Center.

While he says it’s important that the finding is verified by larger studies, he adds this: I would tell any overweight patients at risk for AMD, or with AMD, that it’s probably a good idea to lose some weight, particularly since obesity is associated with so many other diseases.

The research study
The new study involved 102 men and 159 women, aged 60 or older, diagnosed with signs of non-advanced AMD.

Patient interviews documented risk factors, including smoking and alcohol consumption, while a dietary questionnaire detailed total daily intake of calories, carotenoids such as beta carotene and alcohol. Also considered was previous history of cardiovascular disease, cancer, or diabetes, and any regularly used medication.

Height, weight, and blood pressure measurements were taken, and each patient had a thorough eye examination. These tests, along with the food questionnaire, were repeated annually. Patients also self-reported waist and hip measurements, along with documenting physical activity and regular exercise regimes, throughout the study period. The average follow-up time for each patient was 4,6 years, with some followed for as long as seven years.

Progression nearly twice as fast
The result: Patients with a high body mass index (25 to 29, which constitutes overweight, and 30 or more, which is considered obese) experienced the fastest AMD disease progression – nearly twice as fast as those with a lower body mass index.

Moreover, those with a higher waist circumference – indicating a greater amount of weight in the midsection – saw a twofold increased risk for the progression of AMD.

On a more positive note, those who participated in regular exercise saw a reduction in disease progression – up to 25 percent for those who engaged in vigorous activity three times a week or more. This, says Seddon, was independent of any weight loss.

The next step, say researchers, is to discover if losing weight can reverse the path of the disease.


Ethnicity plays role in vision problems

Posted in Eye News on June 12, 2008 by larrazabaleye

(Eyesight – Brief Article)

Ethnicity appears to be associated with children’s vision problems–such as near- and farsightedness–suggest researchers from Ohio State University, Columbus. They found that Asian-American youngsters tend to be myopic, or nearsighted, more than their Hispanic African-American, and white peers while white children present with hyperopia, or farsightedness, with greater frequency than those from other ethnic groups. Astigmatism–an irregular curvature of the cornea that causes blurry vision–was most prevalent among Hispanic youth.

“We don’t really know why these differences exist,” says Karla Zadnik an associate professor of optometry. “It’s probably like most of our modern conditions and diseases–a mix of nature and nurture and factors that interact together. But uncorrected vision [difficulties] are a major public health problem, and a large number of children are visually handicapped in their everyday classroom recreational, and other activities.”

Nearly one out of five Asian-American children in the study was nearsighted, and an equal percentage of white children was farsighted. More than one-third of the Hispanic kids had astigmatism.

The researchers also are studying the rate at which children’s eyes change during their elementary and middle school years. “About two percent of children are nearsighted when they enter school,” Zadnik notes. They “tend to develop myopia between eight and 12 years old. In fact, most first-graders are slightly farsighted when they begin school. As the body grows, that farsightedness tends to decrease. But for reasons that are still unclear, a child’s eyes sometimes keep growing until he or she reaches [the] teen years. It’s this growth that, in some cases, contributes to near-sightedness.”

USA Today (Society for the Advancement of Education), Oct, 2003

Keyboards spread pink eye

Posted in Eye News on June 12, 2008 by larrazabaleye

Whose been using your keyboard? This is what you’ll ask yourself after reading the following study about an outbreak of pink eye that spread through the use of shared keyboards.

In 2002, students at Dartmouth College in New Hampshire, were plagued by a conjunctivitis outbreak that researchers now believe spread through shared keyboards of university computers.

The Centers for Disease Control and Prevention (CDC) in Atlanta were called in to investigate. Heading up the investigation was Dr Cynthia Whitney. They sent their findings in a letter to The New England Journal of Medicine. The original report appeared in the March 15, 2002, issue of the CDC’s Morbidity and Mortality Weekly Report.

Recreating the scenario
In initial scans of about 40 to 60 keyboards taken during the outbreak, the CDC found no sign of conjunctivitis-causing bacteria. However, in later in-depth laboratory experiments, researchers used more sensitive detection techniques. They recreated the scenario by placing bacteria on a keyboard and they were later able to recover samples of the germs from the tainted keyboard.

Whitney says that her team is not sure whether the laboratory experiment mirrored what happens when people use keyboards in real life. Also if the CDC had used more sensitive culturing techniques on the university keyboards in the first place, they might have found the bacteria.

Go wash your hands
What it all boils down to is that the CDC is not yet sure if the keyboards are responsible for spreading germs. In the meantime, Whitney suggests that public computer users start practicing good hygiene, in particular regular hand washing.

Clean hands can prevent a lot more infections than just pink eye. Keyboards are no more likely than any other surface to spread germs. According to Whitney, many other pathogens, such as the ones that cause diarrhoea, skin infections, colds, flu and other respiratory infections, can survive for some time on surfaces.

A case in point is Japan, whose people managed to circumvent the recent deadly severe acute respiratory syndrome (sars) outbreak. Experts believe that the country remained sars-free thanks to a culture of good hygiene and regular hand washing.

How it spreads
Although relatively harmless, conjunctivitis is highly contagious. It can be caused by a virus or a bacterium and leads to inflammation of the eyelids. It spreads easily from person-to-person via contact with eye secretions, coughing and sneezing.

The Dartmouth outbreak occurred in the first two weeks of February 2002, during which time 100 students went to the varsity health centre with conjunctivitis. At first, experts thought the infections were viral, but were not sure because of the large number of cases. Eye cultures collected from 12 students revealed that a bacterium was responsible.

500 students infected
At the end of the outbreak it was estimated that 500 students (10% of the student body) had been struck down with pink eye.

Researchers are still not sure that the germs were spread via keyboards, because conventional wisdom holds that conjunctivitis-causing bacteria do not survive on surfaces. A letter from a Dartmouth student alerted authorities to the possibility of the keyboard spread. The student told the CDC that most students use the public computer terminals up to 20 times a day.


Laser vision can give you ‘super eyes’

Posted in Eye News on June 12, 2008 by larrazabaleye

An article by Jonathan Leake, Science Editor

Top sportsmen, pilots and military personnel are taking advantage of new laser techniques that can make their vision even better than nature can achieve.

They have been attending private clinics pioneering the laser treatment, which can give them eyesight almost two times more powerful than 20/20 vision, the benchmark for perfect sight.

A number of Premiership footballers have booked into clinics for the off-season in July and August. Golfers are among the keenest customers, since vision defects can be a prime cause of mishits. Tiger Woods is one of several players whose game improved after this type of surgery.

Although the Ministry of Defence bans military personnel from such treatments, a number of fighter pilots and special forces soldiers are understood to have undergone the procedure, which is relatively painless. The MoD is expected to lift the restriction after hearing it could save millions of pounds in pensioning off pilots early.

The treatment, known as wavefront technology, can also improve night vision, enabling those who have had it to see objects in the dusk or shadows.

The technique uses satellite mapping technology to build up a 3D image of the lens and cornea so that lasers can be targeted with greater accuracy.

“What makes this treatment different is that we can map out the tiny defects that occur naturally in all eyes and which we could not pinpoint before,” said Julian Stevens, consultant ophthalmologist at Moorfields eye hospital in London. “We can then smooth out the defects using the laser. For the right patients it is a remarkably powerful technique.”

In America, Steve Schallhorn, a former F-14 fighter pilot instructor who retrained as an ophthalmic surgeon, has persuaded the military to offer the treatment to fighter pilots with deteriorating eyesight.

Normally, such pilots risk being pensioned off or assigned to lesser duties if they suffer even slight reductions in vision. The treatment has been so successful that some pilots are said to have even better sight than their untreated colleagues, giving them a potentially crucial advantage in combat.

Similar treatments have been offered to US Navy Seals, the equivalent of Britain’s Special Boat Squadron.

The emergence of the treatment – one of a number of types of laser-based eye surgery – coincides with a surge in the number of people seeking conventional laser eye surgery. A report from the British Society for Refractive Surgery shows that 300,000 Britons are now treated each year.

Those who have had laser treatments include Sir Richard Branson, Nicole Kidman, Courteney Cox, Mel Brown (aka Scary Spice) and Nasser Hussain, the England cricket captain. Sir Elton John has announced similar plans.

One patient of Stevens was Kate Lonnen, 24, an occupational therapist who had the operation along with her brothers Bradley, 30, and Alexander, 28. The three suffered from severe astigmatisms and other defects. “It was amazing to be able to see clearly for the first time in years,” said Lonnen. “It was like waking up.”

There are risks involved in having such surgery, especially at cheaper clinics where doctors may be less experienced and less scrupulous. Last month an investigation by Health Which? said many clinics exaggerated the success of their treatments and failed to warn of side- effects and complications.

However, such warnings are unlikely to reverse the trend to risk surgery rather than spend a lifetime wearing glasses. Lasik, the most popular of the older methods, involves cutting a flap from the surface of the cornea and reshaping the cornea underneath before replacing the flap. It costs up to £1,000 per eye.

Wavefront techniques are costlier but are still usually less than £1,800 per eye, comparing favourably with the lifetime cost of buying spectacles.

Sheraz Daya, director of the Corneoplastic Unit and Eye Bank at Queen Victoria hospital in East Grinstead, said he had treated a tank commander from Syria who flew over just for the operation. “We also get policemen and firemen as well as a lot of golfers – all people for whom good vision is critical for their work.”

Nick Webborn, a doctor who advises the British Paralympic Association on sports medicine, said the operation had changed his life. “I am in a wheelchair so spectacles and contact lenses are an even bigger nuisance.”

Keith Williams, medical director of Laser Vision Europe in Harley Street, London, has treated Mel Brown, Roger Taylor, the drummer for Queen, and the actor Tony Robinson. He said patients should beware that for a minority the operation does not work. “People react differently and we cannot always predict how,” he said.

(The Sunday Times. 9th March 2003)

Dry Eye: Often Ignored

Posted in Eye News on June 12, 2008 by larrazabaleye

Many people experience an inadequate tear film or eye discomfort some time in their lives. In may be in an airplane, a dry, overheated room or a dusty workplace. But there may be more than 10 million Americans who have a significant dry eye condition that may be related to other symptoms.

The classic Sjogren’s-Associated dry eye affects up to two percent of the population. This triad of symptoms includes: dry eye, dry mouth and arthritis. Dry eyes can be caused by medication, dehydration, inflammation of the eyelids and/or skin, previous eye surgery, systemic diseases such as rheumatoid arthritis, thyroid disease, lupus, sarcoidosis and even poor blinking habits (such as staring at a computer).

Tears at not just water. They have three separate components: 1.) Oil (from the Meibomian oil glands in the eyelids); 2.) Mucous (from the goblet cells deep inside the eyelid); 3.) watery tears (the “aqueous” tears from the lachrymal gland and accessory lachrymal glands located in the conjunctiva of the eyelids).

The innermost layer of tears in direct contact with the eye is the mucous layer, which is also call mucin. The mucin coats the surface of the cornea. The middle layer is the watery tears, which stick to the mucin and keep the eye moist. The outer tear layer is composed of oil from the Meibomian glands; it is deposited like an oil slick on the outside of the watery tears to slow their evaporation from the surface of the eye. Every time you blink you sweep the tears across the cornea and into the drainage ducts called puncta.

The tear film can be evaluated by the use of vital dyes, breakup time, measurement of tear production (Schirmer test) and even some very fancy measurements of thickness and chemical constitution of the tear film. However, your symptoms will often be your best guide.

The symptoms include irritation, burning, redness, mucous accumulations, itching and even light sensitivity. In fact when cells fall off the cornea, it can be downright painful. Having mild eye muscle problems or having inadequate reading glasses may make the symptoms worse. A routine eye examination will exclude other causes of irritation such as conjunctivitis, faulty glasses or contact lens trouble.

It is important to recognize that this low-grade, chronic irritation is actually a medical problem, so you should begin getting help.

Therapy is directed at supplying wetting drops, reducing inflammation, improving your environment and evaluating your drugs and diet.

  1. Use artificial tears: These may be non-preserved (sometimes expensive and inconvenient); minimally preserved or fully preserved. See the Dry Eye chapter in “The Eye Care Revolution” for more details. There are some new types of artificial tears that give patients more options Thera tears has been well-received by many patients. Similsan is a homeopathic eye drop. Cyclosporine A is a new anti-inflammatory drop that attacks the inflammatory nature of some peoples’ condition. Researchers are looking at estrogen and essential fatty acids as other ways to fortify the tear film. Ointments at bedtime are often helpful in reducing morning symptoms.
  2. Punctal plugs: These will reduce tear loss. Every time you blink, tears exit through the little holes (puncta) in the inner corner of your eyelids. By plugging the exit route, the tears you make or supplied by eye drops, will remain longer. Many companies make these removable plugs, which can be tried for either short or long periods.
  3. Environment: Take a careful look at your home (especially bedroom) and workplace. Is it too dry? Is there any humidity? Are there plants? If you suffer from dry eye symptoms especially in the winter, place a humidifier in your bedroom. Any changes in your environment, such as adding a humidifier to your heating system will be helpful.
  4. Evaluate your diet: Are you drinking enough water? Drink at least six to eight glasses of water a day, and limit sodas, caffeine and alcohol. Include fish, soy and other legumes, and seeds such as flaxseed in your diet. These provide essential fatty acids to protect cells and stabilize the tear film. Green leafy vegetables and to a lesser extent meat supply the B vitamins. Those supplements that are good for arthritis appear to be build up other membranes such conjunctiva, mouth, nose and ears. Omega-3 and -6 fatty acids, which come from plants (such as flaxseed, oil of evening primrose, borage) or from cold water fish (such as salmon, mackerel, sardines, halibut and cod) are loaded with these good fats. A good supplement is approximately 500 mg of DHA (fish oil), or flaxseed oil twice daily with meals. People also report that glucosamine sulfate, chondroitin sulfate and gelatin have also helped their eyes, in addition to their arthritis. Promote good digestion through water intake, exercise, lactobacillus and even digestive enzymes if necessary.
  5. Medications: Check out your current medications. Common drugs for intestinal problems, depression, allergy and colds may dehydrate sensitive tissues in your body. If they are necessary, you may have to compensate for this dehydration by drinking more water. Ask you pharmacist or doctor if any of your current medications may cause dry eye.
  6. Remember to blink. Many of us stare at computers and get lost in our work and simply forget to blink. Other people have weak lower lids, which do not contribute the necessary 20 percent to completing a blink. Your or your eye doctor may notice that the lower lid doesn’t move with a routine blink. Fortunately, with a forced or voluntary blink, you can close the eye. Inadequate eye closure while sleeping may also contribute to dry eye symptoms.
  7. Treat associated problems: Conjunctivitis or blepharitis (inflammation of the eye lid) will contribute to symptoms and can be treated with a program of short-term antibiotic therapy. Recognize that many people who have dry eye will experience headaches, neckaches and other generalized complaints and may not recognize that the dry eye problem is fundamental to their constellation of symptoms. Be aware, take a minute to think about it, and determine if you suffer from this condition. Dry eye may be a hidden cause of your headache and discomfort.

Dry eye syndrome is a frustrating condition that may involve more than your eyes. There are many ways that you can help yourself and numerous suggestions that can be made by your eye doctor. Be specific about your complaints, the time of day you experience them, and whether they are aggravated by reading or other activity, and other non-eye symptoms that may not seem to be related. If you are ever intending to undergo eye surgery be sure dry eye problems have been addressed ahead of time.