Health Watch

World Glaucoma Week - March 11-17,2012:

Don't let glaucoma darken your life!

Dr. Madhuwanthi Dissanayake

Glaucoma is a potentially blinding eye condition. It refers to a group of eye diseases which lead to progressive damage of the optic nerve (the nerve that connects the eye to the brain). It is the second leading cause of blindness in the world.

Glaucoma is a progressive optic neuropathy with characteristic changes in the optic nerve head and corresponding loss of visual field that is associated frequently but not invariably with a raised intra ocular pressure (IOP). It encompasses so many different sub types which have varied symptoms, pathophysiology and therefore treatment options.

Glaucoma is known to be the sneak thief of sight where undetected and untreated patient ends up in blindness.

How does it come about?

The human eye is a fluid filled cavity where the volume is relatively constant. The pressure with in the eye is maintained by a fluid within the eye which is continuously being secreted and drained. It is called the aquous humour. If due to any reason, this smooth passage of fluid is disturbed, the pressure in the eye goes up. If it occurs suddenly the pressure rise is acute and causes acute symptoms such as severe eye pain. If the pressure rise is long standing it is symptomless, but the optic nerve damage is progressing.

Symptoms

Symptoms depend on the subtype of glaucoma. In acute (sudden onset) Glaucoma the main symptom is the eye pain. In chronic (Long standing) glaucoma e.g. Primary open angle glaucoma, most of the patients are symptomless.

Primary open angle glaucoma is a sub type that occurs more commonly in the elderly. It is characterised by increase in intraocular pressure (IOP < 21mmHg), an open drainage angle, glaucomatous optic nerve head damage and visual field loss. The risk factors include Age (most after 65 years ), Race (common in black more than the white),Family history, Myopia and Retinal diseases.

POAG is asymptomatic until a significant part of the visual field is lost and hence the presentation is late.

On the contrary in acute angle closure glaucoma occurring commonly in elderly female patients, the presentation is acute.

Starting as a slight blurring of vision sometimes with visualization of halos( like rainbows),progressing to severe eye pain, redness and difficulty of looking at light and reduced vision. Sometimes the patient has severe headache, abdominal pain and vomiting that she may end up getting admitted to a medical or a surgical ward than an eye ward.

This condition, if not detected and treated immediately, the acute IOP rise will cause permanent optic nerve dame and irreversible blindness.

Another fairly common sub type in Sri Lanka is the normotensive (normal tension) glaucoma where the eye pressure is within normal limits but with progressive optic nerve damage such as visual field defects.

Predisposing causes of glaucoma Genetic factors, congenital defects, previous eye trauma, ocular inflammation, cataract, long term uncontrolled diabetes and the use of steroid medications can be associated with glaucoma.

Glaucoma is more common in diabetics. About 5 % of diabetics have glaucoma. Mainly two types of glaucoma can affect the diabetic patients. In one type (POAG) usually the patient is symptomless. Increased intra ocular pressure damages the optic nerve leading to progressive visual field loss.

The second type (neovascular glaucoma) occurs due to long term uncontrolled diabetics.

Here the lack of blood supply to the inside of the eye (retina) causes growing of new blood vessels in the iridocorneal angle. This results in poor absorption of fluid from the eye. As a result the pressure inside the eye will go up rapidly, leading to pain in the eye.

How to know whether you have glaucoma?

Since glaucoma is mostly a symptomless disease in the initial stages, only an eye examination will help in the diagnosis. In the process of the diagnosis your eye doctor will carry out several tests such as measuring the intraocular pressure (IOP), visual field assessment (HVF), and assessing the optic nerve (GDX).

As glaucoma is more common in diabetics it will be important to get screened when you go for your annual eye examination for diabetic retinopathy. If you have a family history of glaucoma or if you are shortsighted it would be important to get screened annually specially if you are over the age of 40 years.

Treatment options

In the assessment of the patient intraocular pressure (IOP), assessment of visual field and gonioscopy to assess the drainage angle are performed in addition to the routine visual acuity and refraction.

Treatment depends on the subtype and the options include topical medications (eye drops),oral medications, laser treatment and surgery.

The main aim in the treatment is to minimize the progressive optic nerve damage

This is mainly achieved by reducing the intra ocular pressure. This can be done with oral tablets as well as eye drops. Taking the long term usage into consideration, eye drops are at an advantage to minimize the side effects.

There are different groups of eye drops ranging from once a day administration to 3 times a day. Some can have side effects like redness in the eye and darkening around the eyes.

Another eye drop (Timolol) should not be taken by patients with a past history of asthmatic attacks.

Other treatment options are laser treatment and surgery in selected cases.

Whatever the eye drop you are using it is very important to use it regularly in the correct dosage as this will minimize the optic nerve damage.

As glaucoma treatment should be continued long term the patient should fully understand the importance of the continuous usage of treatment.

As the patient does not feel any improvement or worsening, it is important to monitor the disease with regular eye pressure checking and visual field assessment etc.

The writer is a
Consultant Eye
Surgeon / Head,
Department of
Anatomy,
Faculty of Medicine, University of Colombo

A daily cup of tea, for a healthy heart and body

Studies have shown that a simple cup of tea can help improve heart (cardiovascular) health. The secret is in a class of compounds called flavonoids, found in your tea.

“The health benefits of tea are mainly derived from its antioxidant properties. Studies all over the world have shown that tea is very rich in a class of compounds called flavonoids. The most prominent effect of flavonoids is its anti-oxidant properties. Anti-oxidants have been found to reduce the risk of heart diseases, such as heart attacks,” said Dr Tissa Amarakoon, a senior lecturer at the Department of Chemistry at the University of Kelaniya and a former Deputy Director of the Tea Research Institute of Sri Lanka.

The anti-oxidant properties in flavonoids work by reducing the oxidisation of fat molecules in our bodies, thereby reducing fat deposits on walls of arteries that pump blood to the heart. This makes tea a simple but effective defence against heart attacks.

Flavonoids also help in other ways. Many in vitro studies that investigated the effects of flavonoids on relaxing isolated arteries, have confirmed the vasodilatory effects of flavonoids derived from foods such as wine, grape products, cocoa and tea.

These in vitro studies indicate that flavonoids help to increase production of Nitrous Oxide (NO) that contributes towards the relaxation of blood vessels. This, relaxation of blood vessels makes it easier for the blood to flow through the body.

Studies have shown that black tea has a high percentage (82%) of anti-oxidant flavonoids. The USDA database on flavonoids content in selected foods (2003) , shows that black tea has the highest flavonoid content out of foods such as apples, red onions, blue berries and dark chocolate. Black tea also contributes 60%-84% of dietary flavonoids in western populations.

However, the level of flavonoids in tea may change depending on the cultivar, or the variety of the tea plant, and climatic and soil factors. Leaf size of the tea, whether the tea is bagged or loose, brewing time of the tea and brewing methods, may also have an impact. The good news however, is that the anti-oxidant benefits of tea are not shown to reduce when tea is consumed with milk and sugar. A good amount of flavonoids could be detected in milked teas indicating that milk does not cut down on the flavonoids present in tea due to chemical reactions.

Other studies have shown that tea can induce alertness, together with calming properties. These properties are attributed to the two compounds, caffeine and theanine, that are also found in tea.

“The caffeine in tea contributes to making a person more alert. A substance called theanine, also found in tea, contributes to a calming effect,” said Dr Amarakoon. However, caffeine content in tea is much lower than in beverages such as coffee.

“Generally the content of caffeine in tea, is about half that of coffee. In Sri Lankan tea for instance, the caffeine content in one cup of tea is about 40 mgs, which is a very moderate intake,” explained Dr Amarakoon.

Tea can also contribute to overall health because of its hydrating properties. Contrary to some beliefs that tea can cause dehydration, studies have shown that tea hydrates the body, which helps sustain the body’s natural water balance. Because tea, on its own, without milk or sugar, is a zero calorie beverage, substituting a cup of plain tea for something heavier in calories, can also help you stay leaner, longer.

“In addition to its anti-oxidant properties, tea can also help in a sensible and balanced weight loss programme because tea is a zero calorie beverage. Consuming tea, without sugar, will make it a healthy beverage that does not add to your daily caloric intake. Adding milk to the tea will also not significantly reduce the benefits you get from flavonoids, in terms of anti-oxidant properties,” explained Ms Sigrid de Silva, a Senior Dietician, Nutrition Consultant and Lifestyle and Wellness expert practicing in Sri Lanka.

How you consume your tea may have an impact on the overall benefits derived from your cup of tea. However, in general, a plain, old fashioned cup of tea, can be a low cost investment for long term good health for you and your family.

Early diagnosis of Alzheimer’s Disease

Professor Ralph Martins, a recognised world leader of research into Alzheimer’s disease will deliver a public lecture on ‘Early diagnosis and prevention’ on March 15 at 6 pm at the Lanka Alzheimer’s Foundation auditorium at 110 Ketawalamulla Lane, Colombo 10.

Since the disease’s discovery in 1906, little research work was done until Professor Martins teamed up with Professor Colin Masters and a team of German scientists. They made the first significant discovery showing that the beta amyloid protein that coats the brain is the foundation of Alzheimer’s.

Later Professor Martins made the critical discovery that the Alzheimer’s brain is under oxidative stress. He has been instrumental in new technology that makes it possible to determine if a patient has deposits of the toxic beta amyloid, and therefore allow early treatment before the brain has been irreparably damaged.

As head of the Sir James McCusker Unit for Alzheimer’s Disease Research for over 20 years, and Inaugural Chair for Ageing and Alzheimer's Disease at Edith Cowan University, Professor Martins is working to develop an early diagnostic blood test.

How much iodine is too much?

Amy Norton

A new study looks at excess iodine intake: how much is too much iodine? Excessive iodine in the diet can cause sub clinical hypothyroidism, which has been linked with heart disease.

New York- Iodine deficiency is a major health problem worldwide, but a new study points to the potential downsides of too much iodine.

Iodine is a mineral found in iodized salt, seafood, eggs, dairy and some breads. It is used by the thyroid gland to help regulate metabolism and development, especially in babies and children.

Iodine deficiency during fetal and early-childhood development is a leading cause of brain impairments in much of the world. So most research has been directed at the effects of inadequate iodine.

Less is known about how much iodine is too much. So for the new study, reported in the American Journal of Clinical Nutrition, Chinese researchers randomly assigned healthy adults to take various doses of iodine supplements for four weeks.

They found that at relatively higher doses -- 400 micrograms a day and up -- study participants began developing what's called subclinical hypothyroidism.

That refers to a dip in the body's thyroid hormone levels, but with no obvious symptoms of hypothyroidism -- which include problems like fatigue, depression, dry skin and weight gain.

In this study, people taking 400-microgram supplements were getting around 800 micrograms of iodine per day when diet was factored in.

So the findings suggest that people -- at least in China -- should get no more than 800 micrograms a day, according to the researchers, led by Wanqi Zhang of Tianjin Medical University.

That's different from what's recommended in the U.S., where National Institutes of Health guidelines say the safe upper limit for adults is 1,100 micrograms of iodine per day.

Still, the typical American would get much less than 800 micrograms of iodine a day through diet anyway, according to Dr. Elizabeth Pearce, an associate professor of medicine at Boston University who was not involved in the study.

That said, Pearce cautioned against taking iodine supplements with more than 150 micrograms in a daily dose. And most Americans could skip supplements altogether.

“Overall, we're iodine-sufficient,” said Pearce, who studies iodine sufficiency and thyroid function.

But she said there are certain people who may need supplements, including pregnant women.

In the U.S., adults are advised to get 150 micrograms of iodine each day; pregnant women should get 220 micrograms, while breastfeeding moms are told to get 290 micrograms.

The American Thyroid Association recommends that pregnant and breastfeeding women take a vitamin with iodine because low iodine can increase the risk of miscarriage and thyroid problems in moms, in addition to mental disabilities in babies.

According to Pearce, vegans may also want to take a supplement. In a recent study, Pearce and her colleagues found that the average iodine level in a group of 63 vegans was lower than what's recommended -- though their thyroid hormone levels were in the normal range.

Vegans eschew all animal products, including dairy and eggs, so their iodine sources may be few.

The current findings are based on 256 healthy adults who had normal thyroid when they entered the study. Zhang's team, which did not respond to requests for comment, randomly assigned them to take one of 12 doses of supplemental iodine -- anywhere from 0 to 2,000 micrograms per day, for four weeks.

Of the people who took 400 micrograms, 5 percent developed subclinical hypothyroidism. And the numbers rose in tandem with the iodine dose: Of people on the highest dose (2,000 micrograms per day), 47 percent developed subclinical hypothyroidism.

“These are interesting data,” Pearce said, “because we don't have a lot of information on iodine excess.”

Subclinical hypothyroidism has no obvious symptoms, but studies have linked it to an increased risk of heart disease over the long term, Pearce noted.

Those studies don't prove that subclinical hypothyroidism is to blame. Still, they raise concerns that there could be health consequences.

But in general, Pearce said, it's thought that the effects of your iodine intake may depend on “who you are and where you live.”

In certain parts of the world, the soil is low in iodine, and people who eat mainly local foods have a high risk of deficiency. In other parts of the world -- Japan, for example -- people have a high iodine intake starting early in life, and they seem to “tolerate” that high level, Pearce explained.

In China, natural iodine levels vary by region. The country introduced universal salt iodization in 1996, so the problem of iodine deficiency has been controlled in most areas.

But Pearce said it's not clear if the adults in this study had adequate iodine intake early in life. If not, that could be a factor in their response to iodine supplements.

(Reuters)

Negative effects of air conditioners

L.S.R. Balachandran

At present practically all offices and even wealthy bungalows are air conditioned. People should be aware of the health hazards faced by them if they stay continuously in air conditioned rooms for more than 12 hours.

Your skin will get dry. During summer season it is always better to perspirate more which in turn keep your skin cool and it is healthy.

Those who have skin diseases should not wait in air-conditioned rooms for long.

Intake of water every hour is compulsory.

It is better to leave the A/C rooms after usage of 3 hours. Even at night it is better to stop usage every one hour.