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Advances in Low-Vision Research

New technologies and initiatives are improving quality of life for these patients.

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Low vision— visual impairment caused by diseases of the eye or brain that cannot be corrected by medication, standard eyeglasses, or surgery — currently affects approximately 3 million individuals in the United States. Most commonly caused by age-related macular degeneration, glaucoma, diabetic retinopathy, or corneal opacities, the condition primarily affects the elderly; approximately 90% of those affected are older than 60 years of age.1

As the population continues to age during the next decade, the incidence and prevalence of low vision are expected to double. Consequently, there will be a growing need for partnerships between retinal physicians and vision-rehabilitation specialists, especially in the areas of surgical implants and artificial vision, according to Diane Beasley Whitaker, OD, division chief of Vision Rehabilitation and Performance and assistant professor of Ophthalmology at Duke University School of Medicine.

“I work closely with a large surgical and medical vitreoretinal division at Duke Eye Center,” says Dr. Whitaker, “and most of my referrals come from retinal physicians. Retina specialists appreciate effective visual rehabilitation programs as much or more than any other ophthalmology subspecialists, due to the nature of the blinding eye diseases and retinal conditions they treat but cannot cure. When medical or surgical options have been exhausted or maximized, it is important to avoid telling a patient with low vision that nothing more can be done. In most cases, patients can optimize functional capabilities to improve many areas of their lives — including driving, working, going to school, and performing activities of daily living. Knowledge of and access to rehabilitation resources softens the blow of a devastating diagnosis of progressive or permanent vision loss.”

DEFINING AND ADDRESSING LOW VISION

Dr. Whitaker notes that the term “low vision” was coined by an ophthalmologist in the 1950s and quickly became synonymous with legal blindness. During the past few decades, however, the term has become more nuanced and has expanded to include a wide range of visual deficits, including those due to loss of visual contrast sensitivity, and visual field loss. The classification of visual impairment established by the World Health Organization, for example, recognizes 5 categories that range from moderate visual impairment to total blindness. Yet misconceptions and confusion regarding the meaning of low vision persist.

“Many government agencies in the United States, including the Veterans Affairs system, still use the criteria of legal blindness when determining whether people qualify for low vision resources,” says Dr. Whitaker. “The problem is that most patients struggling with visual impairment are not legally or completely blind. Patients with even mild or moderate visual impairment struggle with their ability to drive, read, or safely and successfully perform other activities. For example, patients with an epiretinal membrane or a macular hole may be just as frustrated or concerned about their abilities as someone with a more severe condition such as retinitis pigmentosa or advanced macular degeneration.”

After thorough evaluation by Dr. Whitaker, her team of therapists train patients to use a range of devices that help them make the most of remaining vision to maximize both independence and quality of life, such as eSight glasses (eSight Corp.), Cyber Eyez (Cyber Timez), NuEyes’ low-vision glasses, a low-vision virtual-reality system by Irisvision Global, MyEye 2.0 glasses (Orcam), and Aira glasses (Aira Tech Corp; more information on low-vision devices is available at www.aao.org/eye-health/diseases/low-vision-aids-rehabilitation ).

“The biggest development in technology in recent years has occurred in the area of wearable devices,” says Dr. Whitaker. “A wearable device is head mounted, so you can wear it like spectacles rather than having to carry it around with you. Think of Google Glass on steroids. We have several types of wearables that we offer our patients, each of which has slightly different features and capabilities.”

The other major platforms available to patients, says Dr. Whitaker, include mainstream devices, such as smart phones and tablets, which have accessibility features built into them. Since 2010, a technology access bill that President Obama signed into law has required the telecommunications industry to enhance user interfaces on smart phones, televisions, computers, and other devices to improve access for visually and hearing-impaired individuals.

“Most people with normal vision aren’t aware that these accessibility features exist, but now, if you pick up a smart phone or a tablet, whether it has an Apple, Android, or Windows platform, these features are built into the hardware. Apple was the first to employ these features, and they hired blind engineers to develop their interfaces in a user-friendly format. We train our patients to access and use these features on all personal devices. There are also growing number of useful apps available to help individuals with poor sight.”

REIMBURSEMENT CHALLENGES

Currently, seeking reimbursement from health insurance providers for low vision devices is even more challenging than trying to qualify for low-vision resources provided by government agencies. However, low-vision provider services are usually covered.

“Most low-vision devices, whether wearable or traditional magnifiers, are not covered by Medicare or third-party payers, so patients have to pay for them out of pocket,” says Dr. Whitaker. “However, that is beginning to change because of advocacy efforts directed toward ensuring that low-vision devices qualify as durable medical equipment (DME), not unlike prosthetic arms or wheel chairs. Surgically implanted low vision devices like the Implantable Miniature Telescope (CentraSight) and Argus II (Second Sight) are considered prosthetic eyes and have Medicare coverage. I would argue that a wearable device that provides visual input should be classified as a prosthesis as well.”

Dr. Whitaker notes that The Centers for Medicare & Medicaid Services (CMS) recently proposed conducting a demonstration project to determine the fiscal impact and feasibility of covering low-vision devices. Meanwhile, according to Brian Mech, PhD, president and CEO of eSight Corporation, and former vice president at Second Sight Medical Products, the manufacturer of the Argus II Retinal Prosthesis System, a few private health insurers are making an effort to cover low-vision devices.

“Some healthcare insurance companies will consider covering these devices on a case-by-case basis,” says Dr. Mech, “and there have been several instances of insurers stepping up to cover the cost of our eSight device [see sidebar]. But there is nothing close to systematic coverage yet. Most vision insurers currently offer only a $1,000 lifetime benefit for related technology, which a patient with low vision will exhaust in the first few months.”

Implanted Devices and Low Vision

Paul Hahn, MD, PhD

Low-vision rehabilitation should be an indispensable complement to a retina practice. We, as retina specialists, typically treat anatomy and not vision, routinely indicating to patients that our treatment goals are to reattach a retina, close a hole, or dry fluid but that visual outcomes are unpredictable. While these treatments optimize visual potential, low vision rehabilitation may be what maximizes the patient’s vision itself.

I learned to truly appreciate the importance of low-vision rehabilitation with my experience implanting the Argus II Retinal Prosthesis System (Second Sight). I was wowed by the restored visual percepts provided by the device, but it was low-vision rehabilitation that provided the key next steps to maximize utility of the device and patient functioning and satisfaction.

Patient expectations are continually increasing. Low-vision rehabilitation in the past may have been reserved for the profoundly blind, whose potential for improvement is obviously limited. I have continued to expand my own indications for low-vision referrals and now consider an evaluation for any type of residual visual complaints despite an optimized anatomy. Specialized devices, nonstandard tints for glasses, or simply a refined refraction may address patient difficulties.

Low-vision rehabilitation is not magic. It requires time-intensive dedication by the specialist and an understanding of low-vision mechanisms and devices. It is an important step that insurance companies are beginning to understand the value of and cover low-vision devices, and I am very hopeful that current investigations by CMS into feasibility of coverage for low-vision devices will pave the way for standardized reimbursement. These efforts are a reflection of the impact of recent and ongoing important advances in low-vision research and device development that certainly bring hope to not only treat disease but to maximize vision.

Dr. Hahn is a vitreoretinal specialist practicing at New Jersey Retina in Teaneck, New Jersey. He reports consultancy to Second Sight Medical and Genentech.

NEI RESEARCH: MORE HOPE ON THE HORIZON

The Low Vision and Blindness Rehabilitation program at the National Eye Institute (NEI) supports work geared toward developing new technologies and rehabilitation strategies intended to minimize the impact of visual impairment. Program director Cheri L. Wiggs, PhD, oversees a broad portfolio of basic and applied-science research that aims to arrive at a deeper understanding of the blind and low-vision experience.

“There are currently many different avenues of research devoted to understanding residual visual functioning and to helping patients learn to use the vision that remains,” says Dr. Wiggs.

She notes, for example, that individuals with AMD often will develop, on their own, a preferred retinal locus (PFL), which involves shifting the area of central vision to another area of the retina. A number of NEI-funded researchers, such as Susana Chung, OD, PhD, professor of optometry and vision science at the University of California, Berkeley, and Preeti Verghese, PhD, senior scientist at the Smith-Kettlewell Eye Research Institute in San Francisco, are using psychophysical methods to understand how PRLs develop and to what extent patients can be trained to use them effectively.

In addition to basic science research, such as that conducted by Dr. Chung and Dr. Verghese, many NEI-funded scientists are focused on the development of adaptive devices for people with low vision, which typically are made available to the public as soon as they are created. For example, James Coughlan, PhD, is a vision engineer at Smith-Kettlewell who has led many projects involving the development and testing of assistive devices enabled by computer and other sensor technologies. One area of his research has been valuable for patients with diabetic retinopathy, who otherwise would encounter poor quality displays when measuring their glucose levels.

In addition to developing adaptive devices that can help visually impaired individuals interact with their environment, other work has focused on how the environment can be adapted to be more accessible. The design of public spaces, with the goal of making them more visually accessible, has been the focus of some research conducted by Gordon E. Legge, PhD, director of the Minnesota Laboratory for Low-Vision Research at the University of Minnesota in Minneapolis. In March 2018, Texas congressman Pete Sessions recognized Legge’s work with the first Inspirational Research Award at an event on Capitol Hill to recognizing the NEI’s 50th anniversary.

“When designing new buildings, we commonly are concerned about ensuring that there are wheelchair ramps and similar accessibility features,” says Dr. Wiggs. “Dr. Legge’s work is focused on bringing awareness to the need to create architecture that is safer for visually impaired individuals to navigate.”

In the many areas of basic and translational research supported by her division at the NEI, Dr. Wiggs says that the ultimate goal is to address current patient needs.

“All of us would of course like to find a cure for these diseases and disorders in the future, but we are very cognizant of the fact that there are people with visual impairment who have needs that must be met right now. We want to support research that aims to understand the experience of these patients and that is directed toward therapies and devices that can help these patients enjoy the activities of daily living that are important to them today.” RP

REFERENCE

  1. National Eye Institute. Low vision tables. Available at https://nei.nih.gov/eyedata/lowvision/tables .