Small Adjustments Can Make a Big Difference on the Visual Demands Students Face in the Classroom

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Posted on 28th August 2012 by Pacific ClearVision Institute in General

American Optometric Association offers tips to help students make the most out of high-tech classrooms

How many hours a day do children spend on computers or other electronic devices? New data from the American Optometric Association’s (AOA) 2012 American Eye-QR consumer survey indicates 60 percent of parents estimate their children spend up to four hours per day at home or in school looking at a computer or digital device screen. With smartboards, tablets and other digital tools being incorporated into daily school curriculums, the technology has students spending much of their time learning and socializing in front of a screen.

“While these high-tech classrooms can greatly enhance learning, they can pose a number of challenges to the visual system,” said Geoffrey Goodfellow, O.D., AOA spokesperson and attending optometrist in the Pediatrics/Binocular Vision Service at the Illinois College of Optometry. “Many of these issues can be solved with frequent breaks, proper set up of computer screens and yearly, comprehensive eye exams by a doctor of optometry.”

Continuous or prolonged use of technology can lead to computer vision syndrome (CVS), which may include eye strain, headaches, fatigue, burning or tired eyes, loss of focus, blurred vision, double vision or head and neck pain. Pre-existing, uncorrected vision problems like farsightedness and astigmatism, difficulty with focusing or eye coordination can also contribute to discomfort associated with computer vision syndrome.

Parents and teachers can help students avoid CVS by encouraging them to follow the 20-20-20 rule. When using technology or doing near work, take a 20-second break, every 20 minutes, and view something 20 feet away. Studies show that people need to rest their eyes to keep them moist. Plus, staring off into the distance helps the eyes from locking into a close-up position.

According to the most recent AOA American Eye-QR survey, 79 percent of parents are concerned that their child may be damaging their eyes due to technology use. Dr. Goodfellow explains, “Since these new classroom devices are so compelling to students, they tend to stare at them and use them for hours at a time, which fatigues their visual system. So, in addition to breaks, holding screens at the right height and distance is extremely important.”

The following AOA guidelines can help prevent or reduce eye and vision problems associated with computer vision syndrome:

  • Check the height and arrangement of the computer. According to optometrists, a computer screen should be 15 to 20 degrees below eye level (about 4 or 5 inches) as measured from the center of the screen and held 20 to 28 inches away from the eyes.
  • Check for glare on the computer screen. If possible, windows or other light sources should not be directly visible when sitting in front of the monitor. If this happens turn the desk or computer to prevent glare on the screen.
  • Reduce the amount of lighting in the room to match the computer screen. A lower-wattage light can be substituted for a bright overhead light or a dimmer switch may be installed to give flexible control of room lighting.
  • Keep blinking. To minimize the chances of developing dry eye when using a computer or digital device, make an effort to blink frequently. Blinking keeps the front surface of the eye moist.

Most importantly, as part of the yearly, back-to-school checklist, students should see a doctor of optometry for a comprehensive eye examination to ensure their eyes are healthy and functioning properly. The American Eye-QR survey revealed 51 percent of parents do not include a visit to the eye doctor as part of their child’s back-to-school routine. Doctors of optometry can conduct specific tests that address and diagnose CVS and other vision and eye health issues, which include:

  • Measuring visual acuity (sharpness and clarity) to assess the extent to which vision may be impaired.
  • Checking to detect and correct nearsightedness, farsightedness or astigmatism.
  • Testing how the eyes focus, move and work together.

“Early detection and treatment are key in correcting vision problems and helping students see clearly,” said Dr. Goodfellow.

Cataract Rates are on the Rise in Americans Age 40 and Older

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Posted on 28th August 2012 by Pacific ClearVision Institute in Cataracts

The incidence of cataracts in the U.S. has risen 19 percent since 2000, impacting nearly 25 million Americans age 40 and older. In fact, more than half of all Americans will develop cataracts by age 80, according to Prevent Blindness America’s Vision Problems in the U.S. report. In response, the American Academy of Ophthalmology’s EyeSmart program is educating the public about cataract risk factors, detection and treatment options during Cataract Awareness Month.

Cataract is a clouding of the eye’s lens, which can make it more difficult to focus light onto the eye’s retina – the light-sensitive tissue that sends images to the brain. Cataracts, a natural part of aging, are the most common cause of vision loss in the U.S. They typically develop slowly, so symptoms may not be immediately apparent. Over time, cataracts can cause vision to become blurry, cloudy, dull, or dim, and can interfere with daily activities.

The good news is that cataracts are almost always treatable with cataract surgery. During cataract surgery, an ophthalmologist – an eye medical doctor with the training and certification to provide the full range of eye care and surgery – removes the eye’s cloudy natural lens and replaces it with a clear artificial lens implant called an intraocular lens (IOL). Cataract surgery is often performed as an outpatient procedure and does not require an overnight hospital stay. Cataract surgery is one of the safest types of surgery, and 90 percent of patients who have cataract surgery enjoy better vision afterward.

“If you notice vision changes, cataracts could be to blame and you might need more than a new pair of glasses,” said David F. Chang, M.D., a clinical correspondent for the American Academy of Ophthalmology and a clinical professor at the University of California, San Francisco. “If you do have a cataract, you should be reassured that it is a normal aging change and not an eye disease. Cataract surgery usually carries an excellent prognosis, and you should talk to your ophthalmologist about whether surgery should be done to restore your eyesight.”

As the aging population grows, it is increasingly important for seniors and their caregivers to understand cataract risks, symptoms, prevention, and treatment options. The American Academy of ophthalmology recommends the following tips to maintain healthy vision:

Get a baseline exam by age 40. All adults should get a baseline eye exam by age 40 when early signs of eye disease and vision changes may start to occur. During this visit, your ophthalmologist will advise you on how often to have follow-up exams.

After age 65, schedule regular eye exams. Anyone age 65 and older should visit an ophthalmologist regularly to detect eye diseases and conditions like cataract early, and to monitor any vision loss. Seniors age 65 and older may qualify for an eye exam and up to 1 year of care at no out of pocket cost through EyeCare America, a public service program of the Foundation of American Academy of Ophthalmology. See if you qualify at www.eyecareamerica.org.

Know your risk factors for cataract. Diabetes, smoking, extensive UV exposure, serious eye injuries, steroid use, and a family history of cataract can increase your risk for developing a cataract.

Reduce your risks to prevent or delay the onset of cataracts. Use sunglasses and hats to protect your eyes from UV damage. Don’t smoke. If you have diabetes, control your blood sugar carefully through diet, exercise and medications if needed.

Talk to your ophthalmologist about your treatment options. Vision loss from cataracts can interfere with daily activities. Talk to your ophthalmologist about whether cataract surgery is right for you. When preparing for surgery, give your doctor your complete medical and eye health history, including a list of medications that you have taken. Some medications can cause the iris to move out of its normal position and may require your ophthalmologist to adjust his or her surgical technique.

Super Glue: Tests Show That Adhesive Could Improve Safety of LASIK Eye Surgery

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Posted on 28th August 2012 by Pacific ClearVision Institute in LASIK

Kansas State University researchers have developed a glue mixture that may reduce risks after laser vision correction surgery.

Stacy Littlechild, a recent bachelor’s degree graduate in biology originally from Wakeeney, is the lead author of two studies that describe a new protocol involving fibrinogen, riboflavin and ultraviolet light that could improve the safety of the corrective surgery.

One study that demonstrates the ability of a glue to bind corneal surfaces has been published in the June edition of the journal Investigative Ophthalmology & Visual Science, or IOVS. Another study details the molecular mechanisms of how the glue creates adhesion and also will be published in IOVS.

LASIK, or laser-assisted in-situ keratomileusis, surgery uses a laser to reshape the cornea, the eye’s outer layer that helps the eye focus. Many patients have the surgery so they do not have to depend on glasses or contact lenses.

During the procedure, a flap is cut in the cornea so that a laser can remove corneal tissue. The hinged flap is returned to its original position and is held on to the laser-modified cornea with nothing but surface tension.

The cornea has a limited ability to firmly re-adhere the LASIK flap and does not fully heal after the procedure, said Gary Conrad, university distinguished professor in the Division of Biology. Conrad, the principal investigator of the research, studies eye development and was Littlechild’s adviser.

“Although LASIK produces a flap that remains clear and normally lays smoothly on the modified corneal surface, if the eye is hit with blunt force trauma — from an auto airbag or a tennis ball, for example — the flap simply peels open again, resulting in contamination inside the cornea and requiring immediate medical attention, which can include corneal transplantation,” he said.

Cornea transplantation replaces part of the cornea with cornea tissue from a donor and is the most common type of organ transplantation in the U.S. Rejection occurs in about 20 percent of cornea transplants, according to the Mayo Clinic.

“Although a cornea transplant is a routine outpatient procedure, we need to do everything we can to avoid such a transplant,” Littlechild said. “These patients are in pain, out of work and can’t see for a few days afterward. If we can decrease the need for transplants by using a glue, then we won’t impede lives as much and protect patients from having future surgeries.”

In the first study, Littlechild tested the glue using corneas removed from dogfish sharks and rabbits to measure adhesive strength.

She discovered that using glue made from fibrinogen and riboflavin and then binding proteins and glue together using ultraviolet light — the type used in tanning salons — provided the best adhesion to keep the cornea’s flap in place. The substance is a nontoxic biodegradable glue that is used in cataract surgery and does not leave a cloudy scar.

“The idea is that if you use the glue, you’ll either reduce or alleviate the risk associated with LASIK surgery,” Littlechild said. “The hope is that you would never have to worry about needing a transplant later.”

In a second study, Littlechild analyzed specific molecular interactions that are responsible for the adhesion. She found that both covalent and zinc-mediated non-covalent mechanisms contributed to the adhesion.

The finding could prompt further development of the glue and could reveal alternative uses throughout the body, Littlechild said. The glue has the potential to bond other body tissues that are similar in chemical and molecular composition to the cornea.

For instance, tendon tissue that connects muscle to bone is similar to the cornea. Tendon tissue often heals slowly because it does not have many blood vessels; likewise, the cornea does not have any blood vessels.

Other collaborators in the research include Gage Brummer, a senior in biochemistry and premedicine, Prairie Village; John Tomich, professor of biochemistry; and Yuntao Zhang, research assistant professor of biology. Scott McCall, a May 2010 bachelor’s graduate in biochemistry, was the lead author on a related study detailing the effects of riboflavin and ultraviolet light used for strengthening the cornea connective tissue to treat keratoconus, the second-most frequent symptom requiring corneal transplantation.

Research funding came from the Maine IDeA Network for Biomedical Research Excellence in support of work at the Mount Desert Island Biological Laboratory in Salisbury Cove, Maine; the Kansas State University Johnson Cancer Research Center; Kansas IDeA Network for Biomedical Research Excellence; National Center for Research Resources; and the National Eye Institute of the National Institutes of Health.

Littlechild plans to attend Cardiff University in Wales, Great Britain, to earn a doctorate in biophysics. Littlechild presented posters at two annual ophthalmology meetings that led to the invitation to continue her research at Cardiff.

“I would not be where I am today without Kansas State University and Dr. Conrad’s continued support and patience,” said Littlechild, who originally applied for a student office job in the Division of Biology until she received a phone call from Conrad. “I owe my undergraduate success and everything that develops from it to Dr. Conrad’s unfailing efforts.”

Cholesterol-Lowering Drugs May Be Linked to Increased Cataract Risk

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Posted on 28th August 2012 by Pacific ClearVision Institute in Cataracts

Patients using cholesterol-lowering statin drugs may be at increased risk of developing age-related cataracts, according to a study — “Age-related Cataract Is Associated with Type 2 Diabetes and Statin Use,” in the August issue of Optometry and Vision Science, official journal of the American Academy of Optometry.

While further research is needed to understand the true nature of the association, the additional risk of cataracts in statin users appears similar to that associated with type 2 diabetes, according to the study by Carolyn M. Machan, OD, and colleagues of University of Waterloo, Ont., Canada.

Statins and Diabetes Both Increase Cataract Risk The study included nearly 6,400 patients seen at the optometry clinic at the University of Waterloo in 2007-08. Of these, 452 patients had type 2 diabetes. Statin treatment and diabetes were evaluated as possible risk factors for age-related cataracts, controlling for other factors including sex, smoking, and high blood pressure.

Fifty-six percent of patients with type 2 diabetes were taking statins, compared to 16 percent of those without diabetes. Both diabetes and statin use were significantly associated with an increased rate of age-related cataracts.

With adjustment for other factors, diabetes was associated with an 82 percent increase in cataract risk and statin use with a 57 percent increase. Statistically, the increase in cataract risk associated with statins was similar to that associated with diabetes.

The associations differed for different types of cataracts. For one specific type long linked to diabetes (posterior subcapsular cataract), the association with diabetes was no longer significant after adjustment for statin treatment.

Despite the high rate of statin use among patients with diabetes, the two risk factors appeared independent of each other. At older ages, the risk of cataracts increased fastest in diabetic patients who took statins and slowest in nondiabetic patients who did not take statins. On average, cataracts developed 5.6 years earlier in diabetic patients who took statins, compared to nondiabetic patients who did not take statins.

Type 2 diabetes is a known risk factor for the development of age-related cataracts — a common vision problem caused by clouding of the crystalline lens of the eye. Studies in animals have shown a clear link between long-term treatment with statins (at high doses) and cataracts.

The new study suggests that statins may also be linked to cataracts in humans. The authors emphasize that the study can’t prove that statins play any role in causing cataracts, but suggest that such a link is biologically plausible.

While further studies are needed, Dr Machan and colleagues emphasize that the known benefits of statin treatment for patients with type 2 diabetes probably outweigh any increased risk of cataracts. They believe their results will help to increase awareness of the risks of treatments for type 2 diabetes, and may encourage the development of alternative cholesterol-lowering drugs that are not associated with an increased risk of cataracts.

Anthony Adams, OD, PhD, Editor-in-Chief of Optometry and Vision Science, comments, “Considering the increase in the prevalence of diabetes and the corresponding increase in the use of statins, the authors feel these findings serve to encourage further research on the long-term effect of statins on the human crystalline lens.”

An Artificial Retina With the Capacity to Restore Normal Vision

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Posted on 28th August 2012 by Pacific ClearVision Institute in Retina

Two researchers at Weill Cornell Medical College have deciphered a mouse’s retina’s neural code and coupled this information to a novel prosthetic device to restore sight to blind mice. The researchers say they have also cracked the code for a monkey retina — which is essentially identical to that of a human — and hope to quickly design and test a device that blind humans can use.

The breakthrough, reported in the Proceedings of the National Academy of Sciences (PNAS), signals a remarkable advance in longstanding efforts to restore vision. Current prosthetics provide blind users with spots and edges of light to help them navigate. This novel device provides the code to restore normal vision. The code is so accurate that it can allow facial features to be discerned and allow animals to track moving images.

The lead researcher, Dr. Sheila Nirenberg, a computational neuroscientist at Weill Cornell, envisions a day when the blind can choose to wear a visor, similar to the one used on the television show Star Trek. The visor’s camera will take in light and use a computer chip to turn it into a code that the brain can translate into an image.

“It’s an exciting time. We can make blind mouse retinas see, and we’re moving as fast as we can to do the same in humans,” says Dr. Nirenberg, a professor in the Department of Physiology and Biophysics and in the Institute for Computational Biomedicine at Weill Cornell. The study’s co-author is Dr. Chethan Pandarinath, who was a graduate student with Dr. Nirenberg and is currently a postdoctoral researcher at Stanford University.

This new approach provides hope for the 25 million people worldwide who suffer from blindness due to diseases of the retina. Because drug therapies help only a small fraction of this population, prosthetic devices are their best option for future sight. “This is the first prosthetic that has the potential to provide normal or near-normal vision because it incorporates the code,” Dr. Nirenberg explains.

Discovering the Code

Normal vision occurs when light falls on photoreceptors in the surface of the retina. The retinal circuitry then processes the signals from the photoreceptors and converts them into a code of neural impulses. These impulses are then sent up to the brain by the retina’s output cells, called ganglion cells. The brain understands this code of neural pulses and can translate it into meaningful images.

Blindness is often caused by diseases of the retina that kill the photoreceptors and destroy the associated circuitry, but typically, in these diseases, the retina’s output cells are spared.

Current prosthetics generally work by driving these surviving cells. Electrodes are implanted into a blind patient’s eye, and they stimulate the ganglion cells with current. But this only produces rough visual fields.

Many groups are working to improve performance by placing more stimulators into the patient’s eye. The hope is that with more stimulators, more ganglion cells in the damaged tissue will be activated, and image quality will improve.

Other research teams are testing use of light-sensitive proteins as an alternate way to stimulate the cells. These proteins are introduced into the retina by gene therapy. Once in the eye, they can target many ganglion cells at once.

But Dr. Nirenberg points out that there’s another critical factor. “Not only is it necessary to stimulate large numbers of cells, but they also have to be stimulated with the right code — the code the retina normally uses to communicate with the brain.”

This is what the authors discovered — and what they incorporated into a novel prosthetic system.

Dr. Nirenberg reasoned that any pattern of light falling on to the retina had to be converted into a general code — a set of equations — that turns light patterns into patterns of electrical pulses. “People have been trying to find the code that does this for simple stimuli, but we knew it had to be generalizable, so that it could work for anything — faces, landscapes, anything that a person sees,” Dr. Nirenberg says.

Vision = Chip Plus Gene Therapy

In a eureka moment, while working on the code for a different reason, Dr. Nirenberg realized that what she was doing could be directly applied to a prosthetic. She and her student, Dr. Pandarinath, immediately went to work on it. They implemented the mathematical equations on a “chip” and combined it with a mini-projector. The chip, which she calls the “encoder” converts images that come into the eye into streams of electrical impulses, and the mini-projector then converts the electrical impulses into light impulses. These light pulses then drive the light-sensitive proteins, which have been put in the ganglion cells, to send the code on up to the brain.

The entire approach was tested on the mouse. The researchers built two prosthetic systems — one with the code and one without. “Incorporating the code had a dramatic impact,” Dr. Nirenberg says. “It jumped the system’s performance up to near-normal levels — that is, there was enough information in the system’s output to reconstruct images of faces, animals — basically anything we attempted.”

In a rigorous series of experiments, the researchers found that the patterns produced by the blind retinas in mice closely matched those produced by normal mouse retinas.

“The reason this system works is two-fold,” Dr. Nirenberg says. “The encoder — the set of equations — is able to mimic retinal transformations for a broad range of stimuli, including natural scenes, and thus produce normal patterns of electrical pulses, and the stimulator (the light sensitive protein) is able to send those pulses on up to the brain.”

“What these findings show is that the critical ingredients for building a highly-effective retinal prosthetic — the retina’s code and a high resolution stimulating method — are now, to a large extent, in place,” reports Dr. Nirenberg.

Dr. Nirenberg says her retinal prosthetic will need to undergo human clinical trials, especially to test safety of the gene therapy component, which delivers the light-sensitive protein. But she anticipates it will be safe since similar gene therapy vectors have been successfully tested for other retinal diseases.

“This has all been thrilling,” Dr. Nirenberg says. “I can’t wait to get started on bringing this approach to patients.”

The study was funded by grants from the National Institutes of Health and Cornell University’s Institute for Computational Biomedicine.

Both Drs. Nirenberg and Pandarinath have a patent application for the prosthetic system filed through Cornell University.

Improving Vision with Cataract Surgery Has Another Benefit: Fewer Broken Hips in Elderly

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Posted on 2nd August 2012 by Pacific ClearVision Institute in Cataracts |General

Elderly patients who undergo cataract surgery may be up to 28% less likely to fall and suffer a crippling hip fracture, a new study finds:

It stands to reason that better vision could help people lower their risk of falling and breaking a hip. That’s what a new study of more than a million Medicare patients found: those who had surgery to remove vision-impairing cataracts were significantly less likely to suffer hip fractures afterward, particularly those who were older and very sick.

The finding may impact a wide swath of the population, given that more than half of Americans will develop cataracts by age 80, according to the National Eye Institute. Previous research also finds that cataract surgery not only improves vision, but also boosts elderly patients’ quality of life, allowing them to engage socially and take part in their community more. Without clear vision, people may have trouble performing day-to-day activities or other pursuits, and may be more likely to succumb to low self-esteem and depression.

Hip fractures, too, are a major health concern among the elderly: a study last fall found that elderly women who broke a hip were at least twice as likely to die in the year following injury than uninjured women. Fall-related injuries are pricey as well, costing the U.S. more than $10 billion in 2000.

Dr. Victoria Tseng and her colleagues at the Warren Alpert Medical School of Brown University looked at a random sample of 1.1 million Medicare beneficiaries aged 65 or older who were diagnosed with cataracts between 2002 and 2009. They compared the rates of hip fractures in 410,809 patients who underwent surgery to remove cataracts with rates in patients who did not. Overall, the researchers found, patients who received cataract surgery were 16% less likely to break a hip in the year after the procedure, but the benefit was most pronounced in older patients.

The oldest patients in the study, those aged 80 to 84, enjoyed the greatest benefits, with 28% fewer fractures. Those with chronic illnesses like heart disease or diabetes were also 26% to 28% less likely to experience a hip fracture after cataract surgery, compared with equally sick patients who didn’t undergo surgery. And patients who had severe cataracts removed had a 23% lower risk of breaking a hip than others who also had severe cataracts but didn’t have surgery.

However, surgery had no impact on fracture risk in younger patients aged 65 to 69. Why? The New York Times reported:

Researchers speculated that the youngest patients having cataract surgery may be very active people who had the surgery in only one eye, which could worsen problems with depth perception and balance, or may include people with serious neurological ailments. They said more study of this age group was needed.

For frailer, older patients, though, cataract surgery, a commonly performed and generally safe outpatient procedure, may offer a vast range of benefits. “Cataract surgery has already been demonstrated to be a cost-effective intervention for visual improvement,” the authors conclude. “The results in this study suggest the need for further investigation of the additional potential benefit of cataract surgery as a cost-effective intervention to decrease the incidence of fractures in the elderly.

“This is elective surgery, and sometimes people think, ‘I’m too sick to have my cataracts out,’ or ‘I’m too old,’” study author Dr. Anne L. Coleman, a professor of ophthalmology at the Jules Stein Eye Institute at the University of California, Los Angeles, told the Times. “But the take-home message from this study is that if you’re starting to have vision problems and the doctor says you have cataracts, you should probably think of having them removed.”

The study was published in The Journal of the American Medical Association.

Novel Therapy May Prevent Damage to the Retina in Diabetic Eye Diseases

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Posted on 2nd August 2012 by Pacific ClearVision Institute in General |Retina

Researchers at the University of Michigan Kellogg Eye Center have identified a compound that could interrupt the chain of events that cause damage to the retina in diabetic retinopathy. The finding is significant because it could lead to a novel therapy that targets two mechanisms at the root of the disease: inflammation and the weakening of the blood barrier that protects the retina.

To date, treatments for diabetic retinopathy, the leading cause of blindness among working-age Americans, have been aimed largely at one of those mechanisms.

In diabetic retinopathy, damage to the retina results, in part, from the activity of vascular endothelial growth factor (VEGF), a protein that weakens the protective blood-retinal barrier. Recent drugs targeting VEGF have exhibited good response for nearly half of the patients with diabetic retinopathy. But researchers believe that there is also an inflammatory component that may contribute to the disease process.

The study, published in the Biochemical Journal, June 2012 [epub ahead of print] identifies a specific protein common to both pathways as an important target in regulating the disease process in which blood vessels become leaky, and provides a drug that may be developed into a therapeutic intervention for patients in which anti-VEGF treatment alone is not sufficient.

“In diabetic retinopathy and a host of other retinal diseases, increases in VEGF and inflammatory factors — some of the same factors that contribute to the response to an infection — cause blood vessels in the eye to leak which, in turn, results in a buildup of fluid in the neural tissue of the retina,” says David A. Antonetti, Ph.D., Professor, Department of Ophthalmology and Visual Sciences and Molecular and Integrative Physiology, who has also been awarded a Jules and Doris Stein Professorship from Research to Prevent Blindness. “This insidious form of modified inflammation can eventually lead to blindness.”

The compound targets atypical protein kinase C (aPKC), required for VEGF to make blood vessels leak. Moreover, Antonetti’s laboratory has demonstrated that the compound is effective at blocking damage from tumor necrosis factor also elevated in diabetic retinopathy that comprises part of the inflammation. Benefits of this compound could extend to therapies for uveitis, or changes to the brain blood vessels in the presence of brain tumors or stroke.

“This is a great leap forward,” says Antonetti. “We’ve identified an important target in regulating blood vessel leakage in the eye and we have a therapy that works in animal models. Our research is in the early stages of development. We still have a long way to go to demonstrate effectiveness of this compound in humans to create a new therapy but the results are very promising.”

Why Hypertension Increases Damage to Eyes of Diabetic Patients

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Posted on 2nd August 2012 by Pacific ClearVision Institute in General |Retina

Hypertension frequently coexists in patients with diabetes. A new University of Georgia study shows why the co-morbid conditions can result in impaired vision.

“Results showed early signals of cell death in eyes from diabetic animals within the first six weeks of elevated blood pressure. Later, the tiny blood vessels around the optic nerve that nourish the retina and affect visual processing showed signs of decay as early as 10 weeks after diabetic animals develop hypertension,” said Azza El-Remessy, assistant professor in the UGA College of Pharmacy and director of the UGA clinical and experimental therapeutics program.

The study examined animals with early and established stages of diabetes that also had hypertension. The results, which highlight the importance of tight glycemic control and blood pressure control to delay diabetes-related vision loss, were published in the June issue of the Journal of Molecular Vision. The study was the first to understand or explain why combining increased blood pressure with diabetes would hurt blood vessels in the eye.

“The fact that controlling blood pressure in diabetic patients is beneficial has been shown through many major clinical trials,” said Islam Mohamed, a third-year clinical and experimental therapeutics graduate student who co-authored the paper with El-Remessy. “Our study highlights the synergistic and immediate interaction between systemic hypertension and diabetes as two independent risk factors for persistent retina damage known as retinopathy. This emphasizes the importance of addressing different cardiovascular risk factors in a holistic approach for improving management and prevention of retinopathy.”

According to the Centers for Disease Control and Prevention, 45 percent of adults in the U.S. suffer from diabetes, hypertension or high levels of cholesterol in the blood called hypercholesterolemia. Approximately 13 percent of U.S. adults suffer from a combination of two of the conditions, and 3 percent have all three.

Early intervention is a key factor in improving the outcome for patients.

“Health care providers, including pharmacists, should stress the importance of the tight control of blood sugar and blood pressure levels for their patients,” El-Remessy said. “Providing patient education and counseling on how each of these metabolic problems independently can have accelerated devastating effects is critical and can result in better prevention and outcomes for the patients.”

Elusive Gene That Causes a Form of Blindness from Birth Dlscovered

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Posted on 2nd August 2012 by Pacific ClearVision Institute in General

Researchers from the Massachusetts Eye and Ear Infirmary, The Children’s Hospital of Philadelphia, Loyola University Chicago Health Sciences Division and their collaborators have isolated an elusive human gene that causes a common form of Leber congenital amaurosis (LCA), a relatively rare but devastating form of early-onset blindness. The new LCA gene is called NMNAT1. Finding the specific gene mutated in patients with LCA is the first step towards developing sight-saving gene therapy.

LCA is an inherited retinal degenerative disease characterized by reduced vision in infancy. Within the first few months of life, parents usually notice a lack of visual responsiveness and unusual roving eye movements known as nystagmus. LCA typically involves only vision problems, but can be accompanied by disease in other organ systems in a minority of patients. LCA is a common reason children are enrolled in schools for the blind.

“The immediate benefit of this discovery is that affected patients with mutations in this new LCA gene now know the cause of their condition,” said Eric Pierce, M.D., Ph.D., co-senior author and director of the Ocular Genomics Institute at Mass. Eye and Ear. “Scientists now have another piece to the puzzle as to why some children are born with LCA and decreased vision. The long-term goal of our research is to develop therapies to limit or prevent vision loss from these disorders.”

NMNAT1 is the 18th identified LCA gene. The gene resides in a region that was known to harbor an LCA gene since 2003, but the specific disease gene has been undiscovered until now. These findings will be published on July 29 in the online edition of Nature Genetics.

To identify NMNAT1, scientists performed whole exome sequencing of the family of two siblings who initially presented for evaluation of LCA but who had no mutations in any of the known LCA genes. Being seen by a multi-disciplinary team that took the case from careful clinical characterization to genetic testing to the research laboratory was an essential ingredient for success.

“By using whole exome sequencing, we found a mutation in a gene that no one could have predicted would be associated with LCA,” said Dr. Pierce.

“Whereas most of the known LCA genes involve dysfunction of retinal ciliary proteins necessary for light detection in the eye, NMNAT1 is uniquely distinguished by being the first metabolic enzyme linked to LCA,” said Marni J. Falk, M.D., co-first author and Clinical Geneticist at The Children’s Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine.

Having found a mutation in NMNAT1 in this one family, the investigators next asked if mutations in NMNAT1 also cause disease in other patients with LCA. Screening of 284 unrelated patients with LCA from the United States, England, France and India allowed them to identify 13 other patients with mutations in NMNAT1 as the cause of their disease.

Drs. Falk, Pierce and colleagues also studied how the identified mutations in NMNAT1 affect the function of the NMNAT1 protein, and thus may cause dysfunction and death of the light sensitive photoreceptor cells in the retina. Working together with Eiko Nakamaru-Ogiso, Ph.D., in the Department of Biochemistry and Biophysics at The University of Pennsylvania, they found that mutations in NMNAT1 appear to decrease the ability of the NMNAT1 protein to produce NAD+, a key mediator of cellular signaling and energetics.

Early treatment for patients with NMNAT1-related LCA could be especially beneficial.

Researchers found that all but the youngest patient with NMNAT1 mutations had damage to the macula, the center of the retina that is needed for central vision. “This 4-year-old girl who doesn’t have central vision loss yet can possibly benefit substantially if we can devise a therapy for her NMNAT1-mediated LCA that prevents her from developing severe central vision loss,” Dr. Pierce said.

Feel-Good Glass for Windows

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Posted on 2nd August 2012 by Pacific ClearVision Institute in General

Daylight acts on our body clock and stimulates the brain. Fraunhofer researchers have made use of this knowledge and worked with industry partners to develop a coating for panes of glass that lets through more light. Above all, it promotes the passage through the glass of those wavelengths of light that govern our hormonal balance.

Most people prefer to live in homes that are airy and flooded with light. Nobody likes to spend much time in a dark and dingy room. That’s no surprise, since daylight gives us energy and has a major impact on our sense of wellbeing. It is a real mood lifter. But not everyone is lucky enough to live in a generously glazed home, and office spaces — where we spend many hours of each day — are often not exactly bright and breezy. Modern heat-insulating, sun-protection glazing for offices and housing doesn’t make things any better, since it isn’t optimized to allow the light that governs our hormonal balance to pass through: instead, a distinctly noticeable percentage of incident sunlight in this effective part of the spectrum is reflected away.

Anti-reflective glass that is more transmissive overall to daylight is reserved for certain special applications, such as in glass covers for photovoltaic modules or in glazing for shop windows. The aim with this kind of glass is to avoid nuisance reflections and to achieve maximum light transmission at the peak emission wavelength of sunlight. This is the wavelength at which the human retina is also most sensitive to light. “However, our biorhythms are not affected by the wavelengths that brighten a room the most, but rather by blue light,” explains graduate engineer Walther Glaubitt, a researcher at the Fraunhofer Institute for Silicate Research ISC in Würzburg. That is why he and his team have developed glass that is designed to be particularly transmissive to light in the blue part of the spectrum. The secret is a special, long-lasting and barely perceptible inorganic coating that is only 0.1 micrometers thick. “Nobody’s ever made glass like this before. It makes you feel as if the window is permanently open,” says Glaubitt. One reason the glass gives this impression is that it exhibits maximum transmission at wavelengths between 450 and 500 nanometers — which is exactly where the effects of blue light are at their strongest.

Lack of light gives rise to sleep disorders

Why is it that the blue part of the light spectrum has such an impact on our sense of wellbeing? “There is a nerve connecting the human retina to the hypothalamus, which is the control center for the autonomic nervous system,” explains Glaubitt’s team colleague Dr. Jörn Probst. Special receptors sit at the end of the nerve connection which are sensitive to blue light, converting it into light-and-dark signals and sending these to the area of the brain that functions as our biological clock. There, one of the things these nerve impulses do is regulate melatonin levels. A lack of light leads to high levels of melatonin, which can result in problems sleeping and concentrating, as well as depression and other psychological impairments. Seasonal affective disorder, also known as winter depression, is one possible outcome of unusually high melatonin levels. “The coating we’ve developed helps people to feel they can perform better and makes it less likely they will fall ill,” says Probst.

Industrial partner Centrosolar Glas GmbH & Co. KG is responsible for applying the coating to the glass while UNIGLAS GmbH & Co. KG, the company that brought the product to market maturity, handles the remaining finishing work as well as sales. It is about to launch a triple-glazing product featuring this innovative glass, for which a patent is pending, under the name UNIGLAS | VITAL® feel-good glass. Fitting triple glazing to a room does not make it seem appreciably darker, but it does affect the light that enters the room in a way that is detrimental to our biorhythms. This is especially true for people who have little opportunity to spend time outdoors and are obliged to spend most of their time in rooms with only small windows. “Thanks to the special ISC coating, this is not the case with our UNIGLAS | VITAL® feel-good glass. Instead, the light quality achieved is very close to that of single glazing,” says Thomas Fiedler, the Technical Director of UNIGLAS. Its transmissivity to light is increased across the entire range from 380 to 580 nanometers, which is to say in the portion of the spectrum that is responsible for promoting wellbeing. At 460 nanometers, the light transmissivity of UNIGLAS | VITAL® is 79 percent. Comparable triple glazing only lets through 66 percent of light at this wavelength. Meanwhile, the coating has no impact on the window’s heat-insulating properties.

But the ISC researchers haven’t quite reached their ultimate goal: “Up to now we’ve only applied our special coating to the side of the glass facing into the cavity between panes,” says Glaubitt. “In future we will also be coating the glazing’s exposed surfaces — in other words, the outside and the inside of the window. That will allow us to achieve around 95 percent light transmissivity at 460 nanometers.”