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July 21, 2011, 10:29 PM CT

Smartphone making your eyes tired?

Smartphone making your eyes tired?

Several reports indicate that prolonged viewing of mobile devices and other stereo 3D devices leads to visual discomfort, fatigue and even headaches. As per a new Journal of Vision study, the root cause appears to be the demand on our eyes to focus on the screen and simultaneously adjust to the distance of the content.

Scientifically referred to as vergence-accommodation, this conflict and its effect on viewers of stereo 3D displays are detailed in a recent Journal of Vision article, The Zone of Comfort: Predicting Visual Discomfort with Stereo Displays.

"When watching stereo 3D displays, the eyes must focus � that is, accommodate � to the distance of the screen because that's where the light comes from. At the same time, the eyes must converge to the distance of the stereo content, which appears to be in front of or behind the screen," explains author Martin S. Banks, professor of optometry and vision science, University of California, Berkeley.

Through a series of experiments on 24 adults, the research team observed the interaction between the viewing distance and the direction of the conflict, examining whether placing the content in front of or behind the screen affects viewer discomfort. The results demonstrated that with devices like mobile phones and desktop displays that are viewed at a short distance, stereo content placed in front of the screen � appearing closer to the viewer and into the space of viewer's room � was less comfortable than content placed behind the screen. On the other hand, when viewing at a longer distance such as a movie theater screen, stereo content placed behind the screen �appearing as though the viewer is looking through a window scene behind the screen � was less comfortable.........

Posted by: Mike      Read more         Source


July 5, 2011, 8:12 PM CT

Lifestyle, diet can significantly influence course of macular degeneration

Lifestyle, diet can significantly influence course of macular degeneration
Eating a diet high in vitamin D, as well as the nutrients betaine and methionine, might help reduce the risk of macular degeneration, as per new research conducted by Tufts Medical Center scientists. Their study of identical twins from the US World War II Twin Registry also observed that the more a person smoked, the higher their risk of developing macular degeneration. The study, "Smoking, Dietary Betaine, Methionine, and Vitamin D in Monozygotic Twins with Discordant Macular Degeneration: Epigenetic Implications" reported in the journal Ophthalmology on July 1, is the first to look at identical twin pairs in which one twin had early age-related macular degeneration (AMD), and the other had late stage AMD.

AMD is highly heritable, with genetic factors determining up to 71 percent of the disease's severity as determined by a prior study of this twin registry by this same research team. By examining identical twins with the same genes but whose disease was at different stages, scientists were able to identify environmental and behavioral factors that may contribute to severity of the disease. "We wanted to know why, if they have the same genes, do they have different stages of the disease?'' said lead researcher Johanna M. Seddon, MD, ScM, Director of the Epidemiology and Genetics Service, Tufts Medical Center, and Professor of Ophthalmology, Tufts Universtity School of Medicine.........

Posted by: Mike      Read more         Source


February 7, 2011, 8:07 AM CT

Pivotal discoveries in age-related macular degeneration

Pivotal discoveries in age-related macular degeneration
A team of researchers, led by University of Kentucky ophthalmologist Dr. Jayakrishna Ambati, has discovered a molecular mechanism implicated in geographic atrophy, the major cause of untreatable blindness in the industrialized world.

Their article, "DICER1 Deficit Induces Alu RNA Toxicity in Age-Related Macular Degeneration," was published online by the journal Nature on Feb. 6 (DOI: 10.1038/nature09830).

Concurrent with this discovery, Ambati's laboratory developed two promising therapies for the prevention of the condition. This study also elaborates, for the first time, a disease-causing role for a large section of the human genome once regarded as non-coding "junk DNA".

Geographic atrophy, a condition causing the death of cells in the retina, occurs in the later stages of the "dry type" of macular degeneration, a disease affecting some 10 million older Americans and causing blindness in over 1 million. There is currently no effective therapy for geographic atrophy, as its cause is unknown.

Ambati's team discovered that an accumulation of a toxic type of RNA, called Alu RNA, causes retinal cells to die in patients with geographic atrophy. In a healthy eye, a "Dicer" enzyme degrades the Alu RNA particles.

"We discovered that in patients with geographic atrophy, there is a dramatic reduction of the Dicer enzyme in the retina," said Ambati, professor and vice chair of the Department of Ophthalmology and Visual Sciences and the Dr. E. Vernon and Eloise C. Smith Endowed Chair in Macular Degeneration Research at the UK College of Medicine. "When the levels of Dicer decline, the control system is short-circuited and too much Alu RNA accumulates. This leads to death of the retina."........

Posted by: Mike      Read more         Source


December 10, 2010, 10:58 PM CT

Cataracts: Prevention and Treatment

Cataracts: Prevention and Treatment
There is no foolproof way to prevent cataracts, but certain steps may slow the progression of cataracts. Some evidence suggests that smoking can facilitate cataract development so stopping or reducing the habit could help. Other studies advocate moderation in the consumption of alcohol (three or fewer drinks on a daily basis). Because UV rays can damage tissue, consistently wearing sunglasses can decrease your risk as well. Other active steps that you can take include eating a healthful diet that includes fruits and vegetables, and scheduling eye exams regularly. In addition to looking for cataracts, your doctor will be more likely to catch a number of other potential eye diseases in their early stages if you are going in for routine appointments. Importantly, if you have diabetes, be pro-active in managing the symptoms because high blood sugar can contribute to damage of the proteins that constitute the eye's natural, crystalline lens thereby leading to cataracts or other vision problems. By extension, maintaining a healthy weight can reduce your risk of diabetes. Finally, ask your doctor whether any of your medications put you at an elevated risk for cataracts; some corticosteroids, tranquilizers, and steroidal eye drops may do so.

How are cataracts treated?
If your doctor suspects that you have a cataract in one or both eyes, he or she will use the visual acuity test, a dilated eye exam, and/or a tonometry test to confirm the presence of a cataract. In the early stages of a cataract, simple lifestyle changes-such as enhanced lighting, glare-reducing eyewear, or magnifying lenses-may be sufficient to provide noticeable vision improvements. However, if the cataract has begun to impede your activities of daily living-enjoying television, reading books or newsprint, or operating your vehicle safely-cataract surgery may be warranted. Fortunately, cataract surgery is a routine, generally safe procedure in the United States, and most patients are able to return home the same day. In the most common type of surgery, the physician makes a tiny incision on the eye and uses ultrasound waves to break up the natural lens, which is then extracted via suction. After the cataract has been removed, the surgeon replaces it with an intraocular lens.

Choosing an intraocular lens (IOL) is one of the most important decisions that you must make before surgery. The three types that are currently available include monofocal, multifocal, and accommodating IOLs. As the name suggests, monofocal IOLs only provide vision correction for one distance: near or far. Multifocal IOLs, like bifocals or trifocals, can provide vision correction at more than one distance; the lens is subdivided into rings (like a bullseye), and each ring is designed to correct either near or distance vision. Two major difficulties that many patients encounter with multifocal IOLs are that the brain must learn to reprocess "seeing" in this way and that middle-range vision is still challenging. Finally, accommodating IOLs function like the natural lens and adjust to the eye's movement, which allows for a full range of vision. Currently, Crystalens is the only accommodating IOL that is available in the U.S.

Posted by: Mike      Read more         Source


November 5, 2010, 7:58 AM CT

Gene linked to the spread of eye melanoma.

Gene linked to the spread of eye melanoma.
A cancerous melanoma tumor (dark area, upper right) is seen below the retina.

Harbour laboratory
Scientists at Washington University School of Medicine in St. Louis have identified a gene associated with the spread of eye melanoma.

Eventhough more studies are needed, the scientists say the discovery is an important step in understanding why some tumors spread (metastasize) and others don't. They believe the findings could lead to more effective therapys.

Reporting online in the journal Science Express, the team found mutations in a gene called BAP1 in 84 percent of the metastatic eye tumors they studied. In contrast, the mutation was rare in tumors that did not metastasize.

Metastasis is the most common cause of death in cancer patients, yet little is known about how cancer cells evolve the ability to spread to other parts of the body. There is growing evidence that mutations in so-called metastasis suppressor genes may promote the spread of cancer, while having little to do with earlier stages in the life of a tumor. Very few such genes have been identified, but this finding strongly implicates BAP1 as a new member of that small group.

"Researchers and physicians have been waiting for a rational, therapeutic target that we could use to treat high-risk patients," says first author and Washington University ophthalmologist J. William Harbour, MD. "We believe this discovery may provide insights needed to hasten the development of therapies for these patients".........

Posted by: Janet      Read more         Source


October 19, 2010, 8:51 AM CT

Cataract surgery saves lives

Cataract surgery saves lives
CHICAGOCataract surgery not only improves vision and quality of life for older people, but is also apparently a way to reduce the number of car crashes. The research will be presented today's at the Scientific Program of the 2010 American Academy of Ophthalmology (AAO) Middle East-Africa Council of Ophthalmology (MEACO) Joint Meeting. Cataract surgery not only improves vision and quality of life for older people, but is also apparently a way to reduce the number of car crashes. The research will be presented today's at the Scientific Program of the 2010 American Academy of Ophthalmology (AAO) Middle East-Africa Council of Ophthalmology (MEACO) Joint Meeting. It is the largest, most comprehensive ophthalmic education conference in the world.

There's no question that good vision is essential to avoiding auto crashes. But what's the actual impact of a common, vision-improving therapy like cataract removal on crash rates? And is it significant enough that health systems should make sure people don't wait months between cataract diagnosis and surgery? To answer these questions researcher Jonathon Ng, MD, studied accident rates for Western Australian residents before and after cataract surgery on the first eye. (Commonly a time interval is built in between surgery in the first and second eyes.)........

Posted by: Mike      Read more         Source


October 1, 2010, 5:36 AM CT

Drugs for macular degeneration

Drugs for macular degeneration
(Boston) Scientists from Boston University School of Medicine (BUSM) and the VA Boston Healthcare System have conducted a study that failed to show a difference in efficacy between Bevacizumab (Avastin) and Ranibizumab (Lucentis) for the therapy of age-related macular degeneration (AMD). The study, which appears currently on-line in Eye, is thought to bethe first study to describe one-year outcomes of a prospective, double-masked, randomized clinical trial directly comparing bevacizumab to ranibizuamab. Last October, these same scientists published early, six month outcomes of the same study, which also failed to show a difference in efficacy between these two drugs for treating AMD.

AMD is the leading cause of blindness over the age of 50 in developed Western countries. It presents in two forms, exudative (wet) or nonexudative (dry). Wet AMD is often more visually devastating with a higher risk of blindness. The gold standard of therapy for wet AMD is ranibizumab (Lucentis, Genentech Inc.), which was FDA approved as an eye injection in 2006. Bevacizumab (Avastin, Genentech Inc.) was FDA approved for the therapy of colorectal cancer in 2004, but has also been used worldwide in an off-label fashion as an eye injection for the therapy of wet AMD. Lucenitis costs approximately $2000.00 per injection, while Avastin costs approximately $50.00 per injection. While both drugs have shown independently to be effective in treating wet AMD, it was uncertain if both drugs were equally efficacious or if either one was better.........

Posted by: Mike      Read more         Source


May 6, 2010, 6:46 AM CT

Preventing blindness

Preventing blindness
Oak Ridge National Laboratory researchers Ken Tobin (left) and Tom Karnowski see TRIAD as something that could be a life-changer for people at risk of diabetic retinopathy and other potentially blinding diseases. (Photo by Ron Walli/ORNL)
Automated Medical Diagnostics, a startup company based in Memphis, envisions its product helping to preserve the sight of millions of people who are at risk of vision loss from diabetic retinopathy.

Using Telemedical Retinal Image Analysis and Diagnosis, a technology recently licensed by AMDx from the Department of Energy's Oak Ridge National Laboratory and the University of Tennessee Health Science Center, patients can quickly be screened for the disease in their primary care doctor's office and other remote sites, permitting early detection and referral for diabetic retinopathy and other retinal diseases.

"If diabetic retinopathy is detected early, therapys can preserve vision and significantly reduce the occurence rate of debilitating blindness," said Edward Chaum, an ophthalmologist and Plough Foundation professor of retinal diseases at the UT Health Science Center Hamilton Eye Institute in Memphis. Chaum and ORNL's Ken Tobin, partners in AMDx, led the team that developed a method for teaching computers to aid in the diagnosis of diabetic retinopathy and other blinding eye diseases.

The Web-based technology uses a digital camera that takes pictures of the retina at a primary care physician's office or other remote clinical site. The patient's medical data and retinal images are sent to a server and processed through the patented system that quickly sorts through large databases and finds visually similar images representing equivalent states of diabetic eye disease. This allows diagnoses to be made in seconds so patients will know before they leave the office if they have no eye disease or if they need to follow up with a retinal specialist. Conventional techniques require a patient to wait several days to receive results.........

Posted by: Mike      Read more         Source


March 9, 2010, 8:39 AM CT

Anti-depressants and cataracts

Anti-depressants and cataracts
Some anti-depressant drugs are linked to an increased chance of developing cataracts, as per a new statistical study by scientists at the University of British Columbia, Vancouver Coastal Health Research Institute and McGill University.

The study, based on a database of more than 200,000 Quebec residents aged 65 and older, showed statistical relationships between a diagnosis of cataracts or cataract surgery and the class of drugs called selective serotonin reuptake inhibitors (SSRIs), as well as between cataracts and specific drugs within that class.

Published online today in the journal Ophthalmology, the study does not prove causation but only reveals an association between the use of SSRIs and the development of cataracts. The study could not account for the possibility of smoking - which is a risk factor for cataracts - and additional population-based studies are needed to confirm these findings, the scientists say.

This study of statistical relationships is the first to establish a link between this class of drugs and cataracts in humans. Prior studies in animal models had demonstrated that SSRIs could increase the likelihood of developing the condition.

"When you look at the trade-offs of these drugs, the benefits of treating depression - which can be life-threatening - still outweigh the risk of.........

Posted by: Mike      Read more         Source


February 18, 2010, 9:57 PM CT

Green tea may help fight glaucoma

Green tea may help fight glaucoma
Green tea contains healthful substances that can penetrate eye tissues, raising the possibility that the tea may protect against glaucoma and other eye diseases.

Credit: iStock

Researchers 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 glaucoma and other common eye diseases. It appears in ACS's bi-weekly Journal of Agricultural and Food Chemistry

Chi Pui Pang and his colleagues point out that so-called green tea "catechins" have been among many 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 passed from the stomach and gastrointestinal tract into the tissues of the eye.

Pang and 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 retina, for example, absorbed the highest levels of gallocatechin, while the aqueous humor tended to absorb epigallocatechin. The effects of green tea catechins in reducing harmful oxidative stress in the eye lasted for up to 20 hours. "Our results indicate that green tea consumption could benefit the eye against oxidative stress," the report concludes.........

Posted by: Mike      Read more         Source


January 18, 2010, 7:59 AM CT

Artificial muscles restore ability to blink

Artificial muscles restore ability to blink
Surgeons from UC Davis Medical Center have demonstrated that artificial muscles can restore the ability of patients with facial paralysis to blink, a development that could benefit the thousands of people each year who no longer are able to close their eyelids due to combat-related injuries, stroke, nerve injury or facial surgery.

In addition, the technique, which uses a combination of electrode leads and silicon polymers, could be used to develop synthetic muscles to control other parts of the body. The new procedure is described in an article in the January-recent issue of the Archives of Facial Plastic Surgery

"This is the first-wave use of artificial muscle in any biological system," said Travis Tollefson, a facial plastic surgeon in the UC Davis Department of Otolaryngology Head and Neck Surgery. "But there are a number of ideas and concepts where this technology may play a role".

In their study, Tollefson and colleagues were seeking to develop the protocol and device design for human implantation of electroactive polymer artificial muscle (EPAM) to reproducibly create a long-lasting eyelid blink that will protect the eye and improve facial appearance. EPAM is an emerging technology that has the potential for use in rehabilitating facial movement in patients with paralysis. Electroactive polymers act like human muscles by expanding and contracting, based on variable voltage input levels.........

Posted by: Mike      Read more         Source


January 14, 2010, 7:50 AM CT

Eye test could detect Alzheimer's

Eye test could detect Alzheimer's
A simple and inexpensive eye test could aid detection and diagnosis of major neurological diseases such as Alzheimer's at an earlier stage than is currently possible, as per new research by UCL scientists.

The research, led by Professors Francesca Cordeiro & Stephen Moss and published recently in Cell Death & Disease, demonstrates a new technique that enables retinal, and therefore brain cell death, to be directly measured in real time. The method, demonstrated in an animal model, could not only refine diagnosis of neurodegenerative disorders and help track disease progress; it could also aid the evaluation and development of new therapys.

The technique uses fluorescent markers that attach themselves to the relevant cells and indicate the stage of cell death. The retina is then observed using a customised laser ophthalmoscope. Until now, this kind of technique has only been used in cells in the lab, rather than in live animals. This research is therefore the first ever in vivo demonstration of retinal nerve cell death in Alzheimer's Disease.

Professor Cordeiro, UCL Institute of Ophthalmology, said: "The death of nerve cells is the key event in all neurodegenerative disorders but until now it has not been possible to study cell death in real time. This technique means we should be able to directly observe retinal nerve cell death in patients, which has many advantages in terms of effective diagnosis. This could be critically important since identification of the early stages could lead to successful reversal of the disease progression with therapy.........

Posted by: Daniel      Read more         Source


January 3, 2010, 10:49 AM CT

It's never too late to quit smoking

It's never too late to quit smoking
Need a little extra incentive to kick the habit?

Just in time for New Year's resolutions, a UCLA study finds that even after age 80, smoking continues to increase one's risk for age-related macular degeneration (AMD), the leading cause of blindness in Americans over 65.

The American Journal of Ophthalmology publishes the findings in its January edition.

"The take-home message is that it's never too late to quit smoking," said main author Dr. Anne Coleman, professor of ophthalmology at the Jules Stein Eye Institute at UCLA. "We observed that even older people's eyes will benefit from kicking the habit." .

AMD causes progressive damage to the macula, the center of the retina that allows us to see fine details. When the macula degenerates, people experience darkness or blurring in their central vision, preventing them from being able to read, drive and recognize faces.

After age, smoking is the second most common risk factor for AMD. This study sought to determine whether age influences the effects of smoking on AMD risk.

Coleman and her colleagues followed a group of 1,958 women who underwent retinal photographs at five-year intervals, starting with a baseline exam at age 78. Four percent, or 75 of the women, smoked.........

Posted by: Mike      Read more         Source


November 10, 2009, 8:55 AM CT

The world's most common operation

The world's most common operation
As a number of as 10 million people around the world suffer from cataracts. Thomas Kohnen of the Goethe University in Frankfurt and his coauthors discuss cataract surgery with the implantation of an artificial lens in the current issue of Deutsches rzteblatt International (Dtsch Arztebl Int 2009; 106[43]: 695�).

Blindness is commonly due to opacification of the lens. In Gera number of alone, more than 600,000 cataract operations are performed each year. Cataracts can be either congenital or acquired; age-related opacification of the lens is the most common type. The main symptom of cataract is slowly progressive worsening of vision, but glare disability and nearsightedness can also be signs of the disease.

Cataract operations are now commonly performed on an outpatient basis. The eye is anesthetized, pretreated with antibiotics, and surgically opened. New approaches permit the operation to be performed through an incision smaller than 2 mm. In the phacoemulsification technique, the lens is emulsified and aspirated away through a vibrating hollow needle. The surgeon then implants an intraocular artificial lens. Patients without any other diseases of the eye can achieve a visual acuity of 1.0 or even better. Special optical designs for the artificial lens can further optimize the quality of vision and thereby improve patient satisfaction.........

Posted by: Mike      Read more         Source


November 6, 2009, 8:55 AM CT

Research Study On Near Vision

Research Study On Near Vision
The Cornea and Laser Eye Institute is participating in a research study to determine if an investigational corneal inlay can safely and effectively reduce the need for reading glasses. Dr. Peter Hersh, the study doctor, will perform the procedures.

The investigational AcuFocus Corneal Inlay (ACI) is intended to improve near vision in patients with presbyopia, which is the loss of near vision, and reduce dependency on reading glasses. Qualified participants will receive the procedure at no charge.

Presbyopia, the loss of near vision happens when the eye's natural lens loses the ability to focus light from both far and near objects. As a result, near tasks like reading or computer work are blurry. However, it is possible for far objects to still be clear. Presbyopia is a natural occurrence that happens to most of us by age 45. Patients 45 to 60 years are eligible to participate.

Smaller than a contact lens, the ACI Corneal Inlay looks like a small brown ring. It is 5 microns thick and 3.8 mm across with a small hole in the center. Over 8,000 tiny holes throughout the ACI help maintain the health of the cornea. It is placed within the body of the cornea, directly in front of the pupil. The ACI lets the central rays of light continue on to the retina while blocking out some of the more out-of-focus rays. This is similar to the effect seen when one looks through a small pinhole. This increased focus may improve near vision. With the ACI placed in one eye, the depth of focus is anticipated to provide improved near and in-between vision while having little effect on far away vision.........

Posted by: Mike      Read more         Source


June 3, 2009, 5:14 AM CT

How the Brain Processes What the Eye Sees

How the Brain Processes What the Eye Sees
Scientists at the Center for Molecular and Behavioral Neuroscience (CMBN) at Rutgers University in Newark have identified the need to develop a new framework for understanding "perceptual stability" and how we see the world with their discovery that visual input obtained during eye movements is being processed by the brain but blocked from awareness.

The process of seeing requires the eyes to move so light can hit the photoreceptors at the center of each retina, which then pass that information to the brain. If we were cognizant of the stimulus that passes before the eyes during the two to three times they move every second, however, vision would consist of a series of sensations of rapid motion rather than a stable perception of the world. To achieve perceptual stability, current theory has held that visual information gained during an eye movement is eliminated, as if cut off by a camera's shutter, and removed from processing.

As published in Current Biology (http://www.cell.com/current-biology), significant new research conducted by assistant professor Bart Krekelberg and post-doctoral researcher Tamara L. Watson now shows that theory of saccadic suppression is incorrect and what the brain is doing instead is processing information gained during eye movement but blocking it from being reported.........

Posted by: Daniel      Read more         Source



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