Tuesday, October 27, 2009

Blue light-filtering increases macular pigment, may protect against age-related vision loss

Age-related macular degeneration, a major cause of vision loss, affects millions of older persons

Results of an important new study show that implantation of blue light-filtering intraocular lens (IOLs) at the time of cataract surgery increases a nutritional component of the eye, which may afford protection against the development and/or progression of age-related macular degeneration (AMD).

The study, conducted by leading ophthalmology and vision researchers from the Macular Pigment Research Group at the Waterford Institute of Technology, is published in the October 2009 issue of the high impact journal Investigative Ophthalmology & Visual Science (IOVS).1

AMD is a disease affecting the central part of the retina and is the leading cause of vision loss in the developed world.2 Implantation of lenses that do not filter blue light during cataract surgery has been shown to increase the risk for development and/or progression of AMD.3

"Blue light-filtering lenses filter and block damaging blue light from reaching the retina, which holds the potential of reducing vision loss and improving the quality of life for millions of older patients," said the study's chief investigator, John M. Nolan, Fulbright Scholar, BSc, PhD, deputy director, Macular Pigment Research Group, Waterford Institute of Technology, Waterford, Ireland. "These data represent an important first step in fully realizing the benefits of blue light-filtering in improving a nutritional component of the eye known as macular pigment. There is a strong scientific rationale supported by an ever-growing body of scientific evidence which suggests that macular pigment plays a role in reducing the onset and progression of AMD."

Dr. Nolan and fellow Macular Pigment Research Group researchers discovered an increase in macular pigment levels shortly after cataract surgery among the study patients who had blue light-filtering IOLs implanted.1

"Since prolonged exposure to blue light is harmful to the retina, increased levels of macular pigment are considered a strong surrogate marker for protection against the processes that cause age-related blindness, including AMD," says Dr. Nolan.

According to the study, the potential benefits associated with increased macular pigment resulting from the use of blue light-filtering lenses for prevention and/or decreased progression of AMD would be conferred at the time of cataract surgery and are expected to continue thereafter, over a patient's lifetime.1 This is especially meaningful in the modern era of cataract surgery, which is being performed annually in millions of older persons who live for many years after the procedure, as well as certain patient subgroups, who have had the surgery at an earlier age.2 The researchers note that further studies are needed to confirm the clinical benefit of their findings.1

About the Study

Dr. Nolan and colleagues conducted a prospective study in which 42 patients scheduled for cataract surgery were randomized to implantation with a blue light-filtering acrylic IOL or a standard acrylic IOL (control), with macular pigment optical density measured by a reliable method (heterochromatic flicker photometry), and serum concentrations of the macular carotenoids were quantified by a scientific procedure known as high performance liquid chromatography, prior to surgery and then at several post-procedural time points over a 1-year follow-up period.1

Cataract surgery in older persons, where the natural diseased lens (cataract) is replaced with a clear artificial IOL, has been associated with increased subsequent risk for macular disease,4 perhaps due to increased transmission of potentially injurious short-wavelength (blue) light to the retina.3

Therefore, lens manufacturers have incorporated a blue light-filter into IOLs to help reduce photo-oxidative retinal injury and thereby reduce the risk of new-onset AMD and/or its progression. Evidence suggests that photo-oxidative stress is important in the development of AMD.5 The likelihood of retinal damage is highest for short-wavelength light (blue light). Several parts of the eye, most importantly the lens, act as filters to block short-wavelength light from reaching the retina.4

Macular pigment is thought to protect against AMD because it absorbs short-wavelength (blue) light before it reaches photoreceptors in the retina and because of its antioxidant properties (decreases oxidative stress by quenching free radicals). Portions of the eye behind (posterior to) macular pigment are exposed to approximately six times the amount of blue light in persons having the lowest levels of macular pigment, as compared to those with the highest levels.5 Macular pigment is obtained entirely from the diet and transported to the retina via the blood. Therefore, ongoing research is being conducted to determine to what extent a person's diet may affect AMD. However, the data available to date is in support of such a notion.5

About Cataracts and AMD

As the aging population grows and becomes a larger percentage of the overall population, age-related diseases such as cataracts and AMD will become more prevalent.6

Surgical removal of cataracts – lens that have become clouded from buildup of protein – is the most frequently performed surgery in the U.S.7, with more than 6 million cataract surgeries currently performed each year in the U.S. and Europe combined.7,8 While vision is almost universally improved immediately following cataract removal, implantation of lens that does not filter harmful short wavelength (blue) light may hasten the progression of AMD,5 the leading cause of vision loss in people over the age of 60 in the U.S.9

AMD is a disease that affects part of the back of the eye called the macula, the central part of the retina. The central vision of affected individuals becomes blurry or wavy and can be eventually lost, which severely alters their quality of life.9,10 Approximately 25-30 million individuals are affected worldwide, with the number estimated to triple in the next 25 years.11

For more information go to www.maculardegenerationassociation.org

Thursday, October 22, 2009

NeoVista®, Inc. Completes Enrollment in Pivotal CABERNET™ Study

Neovascular AMD affects hundreds of thousands of patients globally. It is our hope that upon one-year follow-up, the data will support FDA approval in a most timely manner so that retinal surgeons, patients, and heath care systems in the US and around the world will have a cost effective option available for treating this dreadful disease in the immediate future.

NeoVista, Inc. today announced the completion of enrollment in its global 450-patient randomized controlled study of their revolutionary epimacular brachytherapy procedure for the treatment of neovascular age-related macular degeneration (AMD). The Company will now begin the mandated one-year data follow-up before submitting the final clinical module of its Pre-Market Approval (PMA) submission to the FDA.

"It's exciting to reach this long anticipated milestone in the CABERNET Study," said John N. Hendrick, President and CEO of NeoVista. "Neovascular AMD affects hundreds of thousands of patients globally. It is our hope that upon one-year follow-up, the data will support FDA approval in a most timely manner so that retinal surgeons, patients, and heath care systems in the US and around the world will have a cost effective option available for treating this dreadful disease in the immediate future."

The largest study of its kind to date, the multi-center CABERNET (CNV Secondary AMD Treated with BEta RadiatioN Epiretinal Therapy) Study assigned patients into one of two arms: a control arm where patients were administered regular Lucentis® (Genentech, South San Francisco, CA) injections and a one time surgical arm, where patients were administered a dose of strontium-90 beta radiation via a short surgical procedure, followed by concomitant injections of Lucentis when needed. The primary efficacy endpoint for the CABERNET Study is based on one-year follow-up of the surgical arm cohort when compared to the control group.

"The CABERNET Study has brought together multi-disciplinary clinical teams aligned around the mission of addressing the serious problem of neovascular AMD," said Pravin U Dugel, Managing Partner, Retinal Consultants of Arizona, Phoenix, Arizona and principal investigator for the CABERNET Study. "I look forward to the final results of this ambitious clinical trial. More than any other recent trial, this clinical trial has the potential of improving the quality of life and the overall treatment of patients with neovascular AMD. It could potentially have a significant impact on the practice patterns and economics of retinal physicians as well as global health care systems."

For more information go to www.maculardegenerationassociation.org

Tuesday, October 13, 2009

Signs Of Macular Degeneration May Predict Heart Disease

A large study found strong evidence that older people who have age-related macular degeneration (AMD) are at increased risk for coronary heart disease (CHD), although not for stroke. This result adds to mounting evidence that AMD and cardiovascular disease may share some risk factors--smoking, high blood pressure, inflammatory indicators such as C-reactive protein, genetic variants such as complement factor H--and disease mechanisms.

For more information go to www.maculardegenerationassociation.org

Monday, October 5, 2009

Patent-pending process improves eye disease detection

Memphis Business Journal - by Michael Sheffield

A collaboration between two professors at the University of Memphis and Southern College of Optometry could result in earlier detection of retinal diseases through a patent-pending testing process.

The Pseudo 2D Fractal Analysis was developed through a collaboration between Khan Iftekharuddin, associate professor in the Department of Electrical and Computer Engineering at the University of Memphis, and Pinakin Gunvant, assistant professor at Southern College of Optometry.

The process uses light beamed through the back of the retina to measure the thickness of retinal tissue at certain points. If the tissue is thick at the “12 and six o’clock” points, it is an indicator of glaucoma. The reflection of the light provides an indicator of the tissue’s thickness.

Gunvant says previous testing methods were accurate 85% of the time, but the 2D method has proven to be 98% accurate.

“That’s very clinically significant,” Gunvant says. “But you’re not inventing new devices. You’re just analyzing the data better.”

Gunvant and Iftekharuddin were doing separate research, with Gunvant focusing on retinal research at the Southern College and Iftekharuddin doing imaging work at the U of M. Gunvant said neither of the two had any idea the other existed until he looked Iftekharuddin up online. Ironically, the U of M professor was out of the country when Gunvant first contacted him.

“I found him through my good friend, Google, and he was right down the road,” Gunvant says. “If it wasn’t for technology, we might have never met.”

Iftekharuddin had used imaging to detect brain tumors through work with St. Jude Children’s Research Hospital, but hadn’t done any research with glaucoma. He says fractal imaging is able to pick up any irregularities in shapes or signals.

“We just took that and applied it to glaucoma and the results turned out to be excellent,” Iftekharuddin says. “Like any other disease, if you diagnose early you can treat it better.”

Once the two professors ensured the technique worked, the University of Memphis began the patent process, which can take up to three years. But it could also yield a viable product for the school to market and license, says Kevin Boggs, director of technology transfer and research development at the University of Memphis.

Boggs says the length of the patent process won’t prevent the two schools from marketing the product to companies that have a history of licensing patent applications.

“Once they’re familiar with the product, they’ll invest in it knowing the odds of getting a patent,” Boggs says. “There are a couple of options. We could either go with an exclusive or non-exclusive license, but we’d have to look at what would bring the product to the broadest possible market to help the most people.”

Gunvant says the technique could also detect other causes of blindness, like diabetes or macular degeneration. The immediate focus, however, is glaucoma, which is the second-leading cause of blindness in the world and the leading cause of blindness among African-Americans.

Gunvant says the new focus of the research will be trying to reach 100% accuracy.

“I doubt we’ll ever hit 100%, but most scientists get proven wrong in 15 years,” Gunvant says. “Glaucoma is very variable and affects different individuals in different ways. We’d have to do a very large scale study to get better than where we are at the moment.”

Gunvant says the technique probably would not have been perfected without the team effort.

“It’s hard to be an expert in every field, so multi-disciplined collaboration is required,” he says. “When you look at a problem from one angle, your brain gets fried, so you have to have someone else to come in and help you solve it.”

For more information go to www.maculardegenerationassociation.org