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Entries in Eyesight (4)

Monday
Sep102012

Bálint Syndrome: Woman With 20/20 Vision Can't 'See'

Jupiterimages/Thinkstock(NEW YORK) -- A Chicago woman with 20/20 vision hopes to one day "see again" after a series of strokes left her unable to process the scenes around her, according to a new case study.

The 68-year-old woman, dubbed A.S. in the study, thought her vision was failing when she woke up from a nap and fumbled to find her bedroom door.

"We took her to an eye doctor, because we didn't know what it was at the time," her husband, Michael, told the study authors. "They ran tests on her eyes, and she passed them with flying colors!"

A brain scan later revealed A.S. had Bálint syndrome, a rare condition caused by damage to the brain areas that process and integrate visual information.

"Her primary vision is fine," said study author Dr. Murray Flaster, medical director of neurology at Loyola Outpatient Clinic in Maywood, Ill., explaining how the eyes and the nerves that receive visual information remain intact. "It's the second step of relating one thing to another she has trouble with."

A busy neurologist sees a handful of Bálint syndrome cases in a lifetime, according to Flaster. The unusual condition, triggered by strokes or tumors in the back of the brain, restricts the amount of visual information a person can process.

"Basically a person can see things, but they can't gauge their position in space," said Flaster, describing how A.S. was unable to tell where her bedroom wall ended and the doorway began. "It's like a funny sort of tunnel vision."

People with Bálint syndrome are also unable to rely on visual cues to guide their own movements, making simple tasks like tooth-brushing much more complicated.

"Because [A.S.] cannot trust her eyes to direct the toothpaste to her toothbrush, she must put the toothpaste directly in her mouth, and by trial and error move the toothbrush to meet it," Flaster and colleagues wrote in their study, published in the journal Neurology. And "she has learned that she must touch the sink at all times in order to remain oriented -- otherwise her eyes are as good as closed."

The study also describes a 62-year-old man, dubbed J.D., who started showing the strange signs of Bálint syndrome while serving Thanksgiving dinner.

"He was holding the spoon upside down. We all laughed," J.D.'s daughter told the study authors. "We just thought he was tired."

Once a hardworking trucker, J.D. is struggling to adapt to life with Bálint syndrome and suffers from depression, according to the study.

"I think that's the worst part for him because he's a man with a lot of pride who worked all his life, and now he can't do anything," his daughter said.

"Obviously it's distressing for patients," said Flaster, adding that finding ways to recover function is key for living with Bálint syndrome.

A.S. had her son put bright yellow tape around doorways and cupboards to help highlight the edges. And because she can no longer read -- a skill that requires seeing letters in the context of words, and words in the context of sentences -- she traded her morning paper for the radio and listens to books on tape. She hopes her story will prompt research into Bálint syndrome treatments.

"I'm talking to you for one reason," she told the researchers. "Because I think if more people know about it, they won't go through what I've gone through."

Copyright 2012 ABC News Radio

Tuesday
Mar132012

NASA Astronauts' Eyesight Damaged by Long Space Flights

NASA(HOUSTON) -- As American astronauts spend more and more time in space, they've noticed they're returning to Earth with a surprising malady: They cannot focus their eyes properly after they come home, and for some the problem seems permanent.

Astronauts with 20/20 vision found they needed glasses for the first time, says NASA.  A few -- their names withheld to protect their privacy -- were told it would be unwise for them to fly in space again.  At least a couple could no longer pilot private planes.

Now, a team from the University of Texas Health Science Center in Houston has done MRIs on 27 astronauts who spent more than a month in space, and reports in the journal Radiology that 60 percent have intracranial hypertension, or high fluid pressure in the skull.  The more time they spent in flight, the more likely they were to have the problem.

"We've known about vision changes in orbit but in some cases we've actually found that it can be permanent," said Peggy Whitson, who has flown twice on the space station herself and is now chief of the astronaut office.  She spoke with ABC News last year when the pattern among veteran space flyers first became apparent.

A fifth of the astronauts tested showed a flattening of the rear of the eyeball, affecting their ability to focus their eyes.  A third showed expansion of the space surrounding the optic nerve that's normally filled with cerebral spinal fluid.

Dr. Larry Kramer, who led the team at the University of Texas that did the MRIs, said the findings could someday be useful to non-astronauts, but at the moment he's most concerned about space flyers.

"What does this mean when we want to travel beyond Earth orbit, on longer missions to Mars and elsewhere?" he said in an interview with ABC News.  "There's no way to predict it, so we ought to study it now."

Copyright 2012 ABC News Radio

Monday
Feb272012

Research Offers Hope for Halting Macular Degeneration

Reporter's Notebook
By: Jane E. Allen

iStockphoto/Thinkstock(NEW YORK) -- I grew up acutely aware that good vision is precious.

In 1971, at age 46, my mother lost sight in her right eye from a blood clot in the retina. It happened within minutes, and over the years, glaucoma and cataracts took their toll, although she continued plowing through murder mysteries with what she called her “good eye.”

Then, one night in December 2008, Mom casually mentioned that bar codes on food packages looked wavy. I knew visual distortions were a sentinel symptom of age-related macular degeneration (AMD), a leading cause of blindness, and urged her to see her ophthalmologist. Within 36 hours, a retina specialist was injecting a drug called Lucentis into her left eye to protect her central vision and ability to see detail. Since then, my 86-year-old mother has returned every six weeks for an injection of Lucentis, which has largely stabilized the so-called wet form of the disease.

As if having one parent with severe eye disease isn’t troubling enough, my 89-year-old father has been treated for glaucoma, cataracts and the so-called dry form of macular degeneration. However, his vision is so stable that he long ago stopped checking for crooked lines on what’s called an Amsler grid, which he taped inside a kitchen cabinet door more than 25 years ago.

According to the National Eye Institute, more than 1.75 million Americans, aged 40 and older have advanced AMD. There are treatments, but there is no cure -- at least not yet.

Despite my own elevated risk for the disease, stemming from age and family history, this week I got a glimmer of hope that science may keep me from following in my parents’ footsteps. Researchers from UC Santa Barbara, the University of Utah and the University of Iowa reported finding 50 genes that were either overly active or less active in a comparison of donor eyes with and without macular degeneration. The findings are illuminating little-understood aspects of how macular degeneration begins and progresses, according to a study published Thursday in BioMed Central’s journal Genome Medicine.

Not only can these genes “identify people with clinically recognized AMD and distinguish between different advanced types,” some of them also appear linked to abnormal changes occurring in the eye before the disease is diagnosable, said study author Monte J. Radeke, a research scientist at UCSB’s Center for the Study of Macular Degeneration. Knowing how these genes function makes them potentially valuable targets for drug development, he said.

“That’s the most important thing about this article. It points out different pathways that could be involved in the disease progression,” said Dr. Marco Zarbin, chief of ophthalmology at the University of Medicine and Dentistry of New Jersey in Newark. “This is wonderful research because first of all, it shows a number of pathways involved in the disease process, both in the early and later stages, which creates opportunities to create treatments that might be better than what we have now.”

Eye doctors currently cannot really help someone at high risk who hasn’t yet manifested signs of the disease. In addition, the current treatment arsenal remains limited, although some of the many drugs now in clinical trials might potentially prove useful, Zarbin said.

Doctors can halt or slow the progression of wet AMD with injections of Lucentis (ranibizumab), approved in 2005; Avastin (bevacizumab), used off-label; and Eylea (aflibercept), FDA-approved last November. All three drugs, which prevent growth of abnormal and leaky vessels in the retina, appear more effective than Macugen (pegaptanib), which was approved in 2004. A few patients still receive photodynamic therapy with Visudyne (verteporfin), an intravenous drug approved in 2000 that’s activated by light shined into the eye. Patients with some manifestations of dry AMD, such as deposits called drusen, can stave off vision loss by taking a dietary supplement of minerals and vitamins.

Researchers around the globe have found some genes associated with a predisposition to AMD, but the new study “increases our knowledge of the genetic abnormalities that are associated with the different stages of AMD. You’re basically increasing the genetic fingerprint for at-risk patients,” Zarbin said. It’s still too soon to make the information the basis of a screening test, he said.

“If we had perfect treatment for all stages of disease, and perfect treatments that could prevent development of disease before you get it, then genetic screening would make a lot of sense,” Zarbin added.

By identifying genes involved in processes that damage the eye, the findings set the stage for a more sophisticated, multi-pronged approach to treatment. Doctors could develop therapies that target genes associated with inflammation, genes that control programmed cell death (apoptosis) in dry AMD, and genes that drive the formation of leaky blood vessels (angiogenesis) in wet AMD. Doctors might prescribe multiple drugs, kind of like hitting your enemy on several fronts.

Zarbin and Dr. Kang Zhang, director of the Institute for Genomic Medicine and chief of Ophthalmic Genetics at UC San Diego, said they’d like to see the study replicated in larger numbers.

”What I want to see is more connections between genes which give you heightened genetic risk for AMD and the genes identified by these authors,” Zhang said.

Finally, Zhang said one of the practical limitations of the new findings was that they came from cadaver eyes. “It’s not feasible to biopsy human eyes,” he said. He hopes the same kinds of genetic information might be gleaned from blood samples and eventually turned into simple blood tests.

I’m hoping that diagnostic, therapeutic and preventive advances will keep me from ever having to face a needlestick in the eye eight times a year. Unfortunately, I didn’t inherit my mother’s remarkable ability to tolerate pain and discomfort.

Copyright 2012 ABC News Radio

Thursday
Dec022010

Scientisits 'See' New Benefit in Fish Diets

Photo Courtesy - Getty Images(BALTIMORE) -- Eating fish may be the key to saving your eyesight.

Researchers at Johns Hopkins School of Medicine in Baltimore claim that the onset of age-related macular degeneration, or AMD, might be minimized by a diet rich in omega-3 fatty acids, which fish have in abundance.

AMD is prevalent in seniors and is the major cause of blindness in Caucasians.

Lead study author Sheila K. West reported a study of 2,400 people between the ages of 65 and 84 revealed that those who ate less omega-3-rich fish and shellfish were more prone to contracting AMD and being in the advanced stages of the disease.

Seniors in the study group lived in Maryland's Eastern Shore region, where fish and shellfish are a dietary staple.

Copyright 2010 ABC News Radio







ABC News Radio