Nearsightedness

CLINICAL EYE CARE

Myopia incidence piques control efforts, initiatives

It doesn't take a fortune teller to divine that the future is blurry at best; a striking report on global eye and vision health already forewarned that predicament.

As a profession, optometry has been trying to slow the progression of myopia through science for many years.

By mid-century, it could be just as common to encounter someone needing corrective eyewear as it would be to find someone with brown eyes. In other words, half of the world's population will be myopic by 2050, and one-fifth of those will be at a significantly increased risk of blindness, according to the latest World Health Organization report on the condition.  

Published in the Journal of the American Academy of Ophthalmology in 2016, this international meta-analysis determined a seven-fold increase in myopia from 2000 to 2050 will affect nearly 5 billion people—1 billion at risk for high myopia—and become the leading cause of permanent blindness worldwide.  

Uncorrected refractive error, largely caused by myopia, already affects some 108 million people globally and causes a financial burden of nearly $202 billion dollars annually in lost productivity, the study notes. In the U.S., myopia affects nearly 33 percent of the population, but in some east Asian countries, the toll is much higher. High myopia in Taiwanese college freshmen increased from just 26 percent of all myopia in 1988 to 40 percent by 2005, and South Korea saw myopia rates in 19-year-olds jump from 18 to 96 percent in the past 50 years.  

Although myopia's incidence is well-known, it's pathogenesis remains theoretical. Researchers suspect there's more to it than simply genetics, positing a combination of factors, including environmental, could lead to increases in myopia.  

"(Myopia) seems to be increasing too fast to be explained by genetics," Jeffrey J. Walline, O.D., Ph.D., AOA Contact Lens and Cornea Section (CLCS) past-chair was quoted as saying in a CNN article earlier this year.  

"Nobody really knows why the prevalence of myopia is on the rise."  

But that hasn't stopped clinicians and eye health experts from pushing ahead with treatment and prevention measures to control myopia's progression.  

AOA, optometry strive to eliminate avoidable vision loss  

Given the profession's depth of knowledge and expertise, optometry is well-positioned on the forefront of myopia control, and the AOA and its members are intimately involved in initiatives to curb avoidable vision loss.  

This past September, the AOA sponsored a landmark undertaking with the U.S. Food and Drug Administration (FDA) and other members of the eye health community to investigate myopia and develop clinical trials to analyze the efficacy of devices that slow myopia's progression. From this workshop, experts hope to inform premarket evaluation of contact lenses and other devices designed to control myopia progression.  

"As a profession, optometry has been trying to slow the progression of myopia through science for many years," Dr. Walline said in a June 2016 interview with AOA Focus.  

"Most of the scientific experts in myopia control are optometrists, so it is important that we help companies be able to market successful myopia control modalities, because that will allow us to provide more patients with myopia control benefits."  

Optometry also advised the National Academies of Sciences, Engineering and Medicine (National Academies) on a 2016 report that examines the toll of poor eye and vision health through public health strategies. The report set a roadmap toward improved, equitable vision health through recommendations that focus on expanding care, bolstering clinical evidence to support policy decisions and enhance public health capacities to support vision health, among others.  

"The AOA has been one of the strongest voices advocating for better public eye health and vision care," commented Andrea P. Thau, O.D., AOA president, at the time. "We hope this report spurs other stakeholders to follow our lead and convinces policymakers to act and improve access to needed eye health and vision care." 

Glaucoma Care

CLINICAL EYE CAR

New technique could diagnose glaucoma sooner

January is Glaucoma Awareness Month. And as people make New Year's resolutions to improve their lifestyles, they should include adding a comprehensive, dilated eye examination to detect glaucoma, says Leo Semes, O.D.

What this describes is a next-generation imaging device that allows retinal ganglion cells to be visualized.

"If the public made a resolution to get their eyes examined before Valentine's Day...that would be a good message," says Dr. Semes, former professor at the University of Alabama - Birmingham School of Optometry.

It's a good time for doctors of optometry to have a conversation with patients at risk for the second-leading cause of blindness worldwide, Dr. Semes adds. This includes adults over age 60, African Americans and Hispanics over 40, and people with a family history of glaucoma, according to the National Eye Institute (NEI).

Sneaky symptoms, speedier diagnoses
Dr. Semes speaks from personal experience. His grandfather and mother both endured glaucoma. The eye condition influenced their quality of life. "Today we have better means of treatment, which may have resulted in a better outcome for them," Dr. Semes says.

The challenge with glaucoma is that its symptoms sneak up on patients. The earlier the diagnosis the better. A new imaging technique attempts to give eye doctors another option for catching the condition quicker. Published Jan. 2 in the Proceedings of the National Academy of Science of the United States of America, the study, "Imaging individual neurons in the retinal ganglion cell layer of the living eye," looks at retinal ganglion cells (RGCs) whose death are mostly liable for the loss of vision in glaucoma. Researchers in the study took a current technology—confocal adaptive optics scanning light ophthalmoscopy—and adapted it to capture views of separate RGCs within the retinas of a small number of monkeys and humans.

"The ability to image these cells in the living eye could accelerate our understanding of their role in normal vision and provide a diagnostic tool for evaluating new therapies for retinal disease," wrote researchers at the University of Rochester Medical Center.

Intraocular pressure is measured using applanation tonometry. The reading is altered by many factors, the most prominent of which is central corneal thickness, Dr. Semes says.

He also noted that the study's human subjects had normal retinas or early age-related macular degeneration. Individual RGCs have been viewed as hard to detect, described as "nearly perfectly transparent." More work is needed before it can be applied to clinical practice, he says.

Murray Fingeret, O.D., was encouraged by the results but added that more research was needed on the effectiveness of the new technique. Dr. Fingeret is chief of optometry at Department of Veterans Affairs, New York Harbor Healthcare System in Brooklyn, New York, and the first doctor of optometry appointed to the board of directors of The Glaucoma Foundation, where he continues his life's work of research and collaboration to find a cure.

"What this describes is a next-generation imaging device that allows retinal ganglion cells to be visualized," Dr. Fingeret says. "The cells are visualized due to an improvement in the optics of the device using adaptive optics.

"Currently, we image the retina and optic nerve to measure thickness of a tissue, such as the retinal nerve fiber layer, but we are not looking at individual cells," he says. "We are looking at a layer and then measuring its thickness. While this is important and an improvement from where we are now, this technology is still years away from being available commercially and it is not clear if this will be a clinical tool or one for researchers to understand the ways that glaucoma may develop and progress."

Showing promise
Dr. Semes was principal author of the AOA's clinical practice guide, Care of the Patient with Ocular Surface Disorders in 2010; a panel member for the clinical practice guide, Care of the Patient with Retinal Detachment and Related Peripheral Vitreoretinal Disease, and is one of the founding members of the Optometric Glaucoma Society and Optometric Retina Society.

He noted at least one study shortcoming: a possible contamination of the ganglion cell layer measurement in the presence of other neurodegenerative disorders. Otherwise, potentially, the new technique shows promise.

"Damage to the GCL (ganglion cell layer) has been used for several years as supportive (or pivotal evidence in equivocal cases) for a diagnosis and to assess progression in glaucoma," Dr. Semes says. "Recently, retrospective studies have suggested strongly that ganglion-cell loss may be the earliest structural change seen in glaucoma and that its progressive damage indicates an index in the absence of functional (visual field) changes.

"It is my opinion that the ganglion-cell population assessment is a powerful tool for initial insult as well as for assessing the trajectory of progression after baseline is established," he added. "In fact, studies have shown that this parameter may be more sensitive to progression than retinal nerve fiber layer thickness measurements."

An icebreaker
With the national observance of glaucoma, the NEI's National Eye Health Education Program (NEHEP) recently reissued an updated "Keep Vision in Your Future: Glaucoma Toolkit."

Described as science-based and easy to understand, the kit aims to give health professionals tools to educate the public on the importance of comprehensive, dilated eye examinations in halting the progression of glaucoma in patients.

"It is meant for speakers to discuss glaucoma with an audience," says Dr. Fingeret.

"The slides run through who gets glaucoma, how glaucoma is diagnosed, and how it is treated. It is a simple presentation useful to present to patients. The kit comes with a speaker's guide as well as a fact sheet for audience members."

Dr. Semes noted a seeming contradiction in the toolkit's PowerPoint, specifically pages 14 and 19. And he noted that the presentation fails to mention visual field testing, part of a comprehensive evaluation for glaucoma. Still, both doctors applauded the presentation's intent: glaucoma awareness and its focus on the number 1 risk factor for glaucoma, elevated intraocular pressure.

AOA glaucoma resources can be found here and in AOA Marketplace.

JANUARY 9, 2017

Macular Degeneration Injections

 

Anti-VEGF injections may not work for all, new study says

A common treatment for wet age-related macular degeneration (AMD) may need a second thought by doctors of optometry.

 A new study suggests, in some cases, that patients' vision worsens due to intravitreal, anti-vascular endothelial growth factor (VEGF) injections. An estimated 288 million people will suffer from wet AMD by 2040.

“Even minimal amounts of anti-VEGF intravitreally may have other effects in the body, so this needs to be monitored.”

The role of VEGF and its side effects in treatment of wet AMD was examined in a new study first published online in The Journal of Clinic Investigation on Dec. 5, titled "VEGF regulates local inhibitory complement proteins in the eye and kidney." Senior co-authors include Martin Friedlander, M.D., Ph.D., professor in the cell and molecular biology department of The Scripps Howard Research Clinic, and Moin Saleem, MBBS, FRCP, Ph.D., professor of human biology at the University of Bristol.

 According to the authors, "High concentrations of VEGF contribute to CNV (choroidal neovascularization) development, so wet ARMD is treated with intravitreal anti-VEGF injections. This therapy revolutionized ARMD patient care."  

But, apparently, it may not work as well in all patient cases. Not only is there a loss of vision, but there also is damage to cells in the kidneys, researchers say. The treatment may inhibit some patients' capability to make inhibitory complement factor H (CFH), a protective and regulatory molecule, the study says.  

Researchers linked VEGF inhibition with a decrease in CFH.   "Over 40 percent have stable or improved visual acuity, but 10 to 30 percent of patients treated develop reduced visual acuity with regular repeated injections over time," wrote researchers, who noted more research needs to be done on why. "This could be due to the loss of VEGF's trophic effects."  

'Needs to be monitored'  

Steven G. Ferrucci, O.D., is chief of optometry at Sepulveda VA Medical Center and professor at Southern California College of Optometry at Marshall B. Ketchum University.   

The study's results are worth being taken into account by doctors of optometry, Dr. Ferrucci says.  

"The point is that researches feel that even the small amount of anti-VEGF injected intravitreally may have effects outside of the eye," Dr. Ferrucci says. "In this study, they seem to show a link between patients who have anti-VEGF injections for AMD and kidney issues, at least in animal models."  

He adds, "While this is still not clear in humans, the point is that even minimal amounts of anti-VEGF intravitreally may have other effects in the body, so this needs to be monitored. Also, as the study suggests, if patients are not responding to anti-VEGF, perhaps it makes sense to stop rather than to continue treatment."

JANUARY 11, 2017