Scientists have confirmed that the healthful substances found in green tea - renowned for their powerful antioxidant and disease-fighting properties - do penetrate into tissues of the eye. Their new report, the first documenting how the lens, retina, and other eye tissues absorb these substances, raises the possibility that green tea may protect against common eye diseases. It appears in ACS’s bi-weekly Journal of Agricultural and Food Chemistry.

Chi Pui Pang and colleagues point out that so-called green tea “catechins” have been among a number of antioxidants thought capable of protecting the eye. Those include vitamin C, vitamin E, lutein, and zeaxanthin. Until now, however, nobody knew if the catechins in green tea actually penetrated into the tissues of the eye.

Pang and his colleagues resolved that uncertainty in experiments with laboratory rats that drank green tea. Analysis of eye tissues showed beyond a doubt that eye structures absorbed significant amounts of individual catechins. The effects of green tea catechins in reducing harmful oxidative stress in the eye lasted for up to 20 hours.
“In addition to a good overall diet and wearing sunglasses, these results show that green tea may play a beneficial role in protecting the eye against oxidative stress,” adds Dr Ashraf, LASIK surgeon at the Atlanta Vision Institute.

A  study from Tel Aviv University has now found that statins, a class of drugs used to lower cholesterol,  cut the risks of cataracts in men by almost 40%.  The study covered over 180,000 patients between the years of 1998 and 2007 and was published in the February 2010 issue of the Annals of Epidemiology.

From the heart to the head

Dr. Chodick and his colleague Dr. Varda Shalev found that men aged 45 to 54 who took the statins daily to lower their cholesterol levels also lowered their chances of developing cataracts by 38%. For women of about the same age, the risk for cataracts was also cut dramatically, by about 18%.

“People who persistently take statins have tremendously reduced chances of premature death by disease. We began to think that statins, which are proven to prevent cardiovascular disease, may do other good things in the body as well. We started investigating cataracts to show statins’ effects in a more statistical manner,” says Dr. Chodick.

A cataract is  clouding of the crystalline lens in the eye of which leads to poor vision.  It is the number one cause of reversible blindness in the developing world.  It typically progresses slowly so that the sufferer may not even be aware of the problem.  In the U.S., cataracts affect about 60% of both men and women over the age of 60.  It is easily remedied with removal of the cataractous lens and replacing this with an artificial lens implant.

According to a report in the February issue of Archives of Ophthalmology swelling commonly occurs in the corneas of mountain climbers, but does not appear to affect vision at altitudes of up to 6,300 meters (about 20,670 feet).

“High-altitude mountaineering is a popular recreational sport among healthy lowlanders,” the authors write as background information in the article. “As a consequence of the exposure to hypobaric atmospheric conditions with a consecutive decrease in oxygen saturation, high-altitude climbing may lead to acute mountain sickness and the rare but potentially fatal high-altitude cerebral edema.”  Changes to the cornea, the transparent membrane covering the front of the eye, also occur during high-altitude climbs.

The authors studied the effects of high-altitude climbing on corneal thickness among 28 healthy volunteers climbing Mount Muztagh Ata in western China. The mountaineers were randomly assigned to two different ascending paths, with one group being allotted a shorter time to acclimate before ascending to 6,265 meters. Corneal thickness, visual acuity and blood oxygen levels were measured in climbers before, during and after their ascent, and symptoms of acute mountain sickness were also assessed.

Corneal thickness increased with increasing altitude and decreased after descent, and the amount of decrease in blood oxygen levels paralleled this increase. The group with the shorter acclimatization time experienced a greater increase in corneal thickness. However, no significant decrease in visual acuity was observed in either group.

“It seems that visual acuity in healthy corneas is not adversely affected despite the presence of edema at altitudes up to 6,300 meters,” the authors conclude. Atlanta LASIK surgeon, Dr Farooq Ashraf adds this is not the case in patients who’ve had radial keratotomy.  Radial keratotomy is an old refractive procedure in which 4-8 radial incisions are made using surgical blade in order to change the shape of the cornea.  “It has been well documented that high altitudes can severely affect vision in these patients and in some cases a few mountain climbers have become functionally blind at these high altitudes,” Dr. Ashraf adds.  “LASIK, on the other hand, is unaffected by high altitudes during mountain climbs or even deep sea diving.”

Tearing, also known as epiphora, is a condition in which there is an overflow of tears onto the face.  Epiphora can develop at any age. It has a bimodal age distribution.  It occurs usually in the first 12 months of life or in the elderly years above the age of 60. The condition may present symptoms in just one or both eyes. Depending on the severity of symptoms, watering eye can sometimes make daily activities such as reading and driving difficult and uncomfortable.

What are the causes of epiphora (watering eye)?
There are two main causes of epiphora - blocked tear ducts or excessive production of tears.

•    Blocked tear ducts - some humans are born with underdeveloped tear ducts. It is not uncommon for newborns to have watery eyes. Generally, this problem goes away within a few weeks as the ducts develop.

The most common cause of watering eyes among adults and older children is blocked ducts, or ducts that are too narrow. Narrowed tear ducts usually become so as a result of swelling (inflammation).

If a patient’s tear ducts are narrowed or blocked their tears will not be able to drain away and will build up in the tear sac. Stagnant tears in the tear sac increase the risk of infection in that area and the eye will produce a sticky liquid, further exacerbating the problem. Infection can also lead to inflammation on the side of the nose, next to the eye.

Narrow drainage channels on the insides of the eyes (canaliculi) can become blocked. This is caused by swelling or scarring.

•    Ocular surface irritation - irritated eyes may produce more tears than normal as the body tries to rinse the irritant away. The following irritants can cause the over-production of tears:

o    Chemicals, such as fumes, pollutants, and even onions
o    Dry eyes
o    Contact lenses- common reason for patients to undergo LASIK
o    Blepharitis
o    Allergic conjunctivitis
o    An injury to the eye,
o    Entropion (inward-growing eyelash)
o    Ectropion - this is when the lower eyelid turns outwards
o    Lagophthalmos or an incomplete blink mechanism

How is epiphora or tearing diagnosed?
With a proper examination an ophthalmologist can usually diagnosis the etiology of excessive tearing, especially if it is due to an anatomical or structural problem.  Further invasive testing may need to be performed to determine if it is due to poor drainage of the nasolacrimal system.

A probe might be inserted into the narrow drainage channels on the inside of the eye (canaliculi) to see whether they are blocked.

Liquid may be inserted into a tear duct to find out whether it comes out of the patient’s nose. If it is found to be blocked, a dye may be injected to find the exact location of the blockage .

What is the treatment?
Treatment options depend on the etiology and severity of the epiphora. In mild cases doctors may recommend just watchful waiting - doing nothing and monitoring the patient’s progress.

•    Treatment for irritation - if the watering eye is caused by infective conjunctivitis the doctor may prefer to wait for a week or so to see if the problem resolves itself without antibiotics.
•    Dry eyes- treatment with artificial tear products, punctal occlusion, or pharmaceutical treatment.
•    Allergic conjunctivitis is the cause the patient may be prescribed an antihistamine or anti-allergy drops, which are effective in bringing down the inflammation.
•    Entropion - an inward-growing eyelash, or some foreign object that lodged in the eye, the doctor will remove it.  Structural entropion is treated with surgery.
•    Ectropion - the eyelid turns outwards - the patient may need to undergo surgery in which the outer eyelid in place is tightened and resumes its natural shape..
•    Blocked tear ducts - surgery which creates a new channel from the tear sac to the inside of the nose may be necessary. This allows the tears to bypass the blocked part of the tear duct. This surgical procedure is called DCR (dacryocystorhinostomy).

If the drainage channels on the inside of the eye (canaliculi) are narrowed, but not entirely blocked, the doctor may use a probe to make them wider. When the canaliculi are completely blocked an operation may be required.
•    Epiphora (watering eye) in babies - in the majority of cases the condition resolves itself on its own within a few weeks.
Sometimes blockages can be dislodged if you gently massage the tear ducts. Apply light pressure with the finger and thumb to the outside of the baby’s nose.

The 3-D version of Avatar has two images projected on the screen, each image seen by one eye. The images are then merged into one by your brain. If the images aren’t perceived correctly, it will be very difficult to merge or fuse the images into 3-D. The technology behind the Avatar 3-D effects is based on the premise that the viewer has the ability to see 3-D or has good stereovision.

“There are a variety of vision problems which may cause difficulty in viewing 3-D Avatar.  This may cause headaches or at the least make viewing very uncomfortable,” explained Dr. Farooq Ashraf, medical director of the Atlanta Vision Institute.

Research has shown that up to 56% of those 18 to 38 years of age have one or more problems with binocular vision and therefore could have difficulty seeing 3-D. In addition, about five percent of the population have amblyopia (lazy eye) and/or strabismus which makes 3-D viewing impossible.

A new study reported in Investigative Ophthalmology & Visual Science found that UV-blocking contact lenses can reduce or eliminate the effects of the sun’s harmful UV radiation.

According to the article, “Prevention of UV-Induced Damage to the Anterior Segment Using Class I UV Absorbing Hydrogel), overexposure to UV radiation can lead to harmful changes in the cornea, conjunctiva and lens, including cataracts, the most common cause of visual impairment around the globe. According to the researchers, some estimates say that by the year 2050, there will be 167,000 to 830,000 more cases of cataracts.

Dr Ashraf adds that UV light exposure not only puts your skin at risk but also the eyes. Certain eye diseases have been implicated to UV exposure including cataracts, pterygium, and macular degeneration. This study shows that UV blocking contact lenses are beneficial in decrease your risk to UV exposure to the eye. In patients that do not wear contact lenses, such as ones that had LASIK surgery, good UV blocking sunglasses and hats also aid in decreasing UV light exposure. Dr Ashraf adds that these preventative measures are important not only in the summer but also during winter activities such as skiing in which the sun light gets reflected off the snow and can enter the eye.

Dry eye is very common in patients presenting with cataract or wanting refractive surgery, said Kerry D. Solomon, M.D., Charleston, South Carolina. “These are people whose ocular surface disease has made contact lenses or spectacles uncomfortable,” Dr. Solomon said speaking during an EyeWorld Educational Symposia. The ocular surface is the refractive surface of the eye, he said, and dry eye is the most common complaint after LASIK. “Keep in mind that one in four or one in five patients presenting in your offices has dry eye,” he said. Dr Ashraf, Atlanta LASIK surgeon, adds that preoperative screening for dry eyes prior to LASIK is very important. “With screening and aggressive treatment prior to surgery, our post LASIK dry eye complaints have decreased tremendously over the past year,” adds Dr Ashraf.

The report notes that 16.3 million surgeries have been performed worldwide to date, and about one million LASIK surgeries are done annually in the United States. This peer-reviewed report provides a systematic worldwide overview of LASIK patient satisfaction as of 2008. Report findings were first released last year by the American Society of Cataract and Refractive Surgery (ASCRS). LASIK has been assessed and improved by more than a decade of clinical studies and technological innovation since the procedure was introduced.

The review found an overall patient satisfaction rate of 95.4 percent (2,097 of 2,198 subjects), with a range of 87.2 to 100 percent.. For an elective surgery like LASIK, satisfaction criteria include whether the patients’ physical, emotional, and financial expectations are met and physical and psychological benefits achieved.

The researchers looked at whether patient satisfaction with LASIK has changed over time by comparing rates for surgeries performed 1995 to 2000 with those performed 2001 and after. The rate was 96.0 percent in the earlier period and 94.6 percent in the later period, confirming consistently high patient satisfaction. The review also analyzed satisfaction rates in relation to questionnaire characteristics, administration methods and timing, type of patient refractive error (near- or farsightedness, astigmatism) and country. All analyses showed very high overall patient satisfaction rates. Questionnaires used in all studies allowed patients to rate their satisfaction on graduated scales, from “satisfied” to “dissatisfied.” Five articles offered an “undecided” category, and patients who selected this option were not included in the review analysis.

The research team reviewed 19 studies from 13 countries representing the U.S. and most areas of the world, encompassing 2,198 subjects who had LASIK between 1995 and 2003. A comprehensive international literature search performed by a Storm Eye Institute panel had indentified 309 peer-reviewed, well-designed studies of primary (original) LASIK surgery, of which 19 reported on both patient quality of life and satisfaction. All were randomized, controlled clinical trials, or cohort or case-controlled studies.

“This surgery confirms what patients and physicians performing LASIK have known all along, that LASIK surgery is safe, effective, and yields very few side effects.” adds Atlanta LASIK surgeon Dr Ashraf of the Atlanta Vision Institute.

April 2009 Issue of Ophthalmology.