Researchers Restore Vision in Canine Model of
Childhood Blindness
(From Foundation Fighting Blindness)

In one of the single most important advances in the history of retinal degeneration research, a group of scientists used gene therapy to restore vision in a canine model of severe childhood
blindness known as Leber Congenital Amaurosis (LCA). This was the first time researchers successfully restored vision in a
large animal model of retinal degeneration. Previously, researchers have restored vision in rodents. However, the FDA wants to be assured of safety in the large animal model before giving permission to begin human trials. LCA is the name given to a group of severe, early-onset
forms of retinal degeneration. Infants born with LCA have very little if any existing vision and usually develop unusual roving eye movements. In 1997, researchers discovered that mutations in the RPE65 gene cause a form of LCA. In 1998, researchers cloned the canine RPE65 gene and identified the mutation that is responsible for the disease in Briard dogs. Applying the knowledge gained from these discoveries, a group of researchers hypothesized that replacing the dysfunctional
RPE65 gene with a healthy gene might restore RPE cell function and thereby engage the idle but still healthy photoreceptor cells. The team treated four Briard dogs, a canine breed that, like humans, is genetically susceptible to this
form of LCA. Twelve weeks after a subretinal injection of the RPE65 gene and a viral vector to deliver the gene to RPE cells, ERG tests revealed remarkable improvement in retinal
function. Behavioral testing revealed these canines had regained ambulatory vision even under dim lighting.

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Braving the Low Vision Examination
(by Cydney Strand, RN - Lighthouse International)

The misunderstanding of what low vision care is--and is not--often causes confusion and frustration. Low vision care is about rehabilitation, not cure. It’s about finding new ways to accomplish the tasks of daily life--whether it’s writing a grocery list, watching a grandchild play soccer or reading a menu in a restaurant.

A low vision examination, often the first step in vision rehabilitation, is designed to accurately measure how one’s vision works in the real world--how it functions in day-to-day living. It’s not only about how well you can see an eye chart, but also how well you can see faces, street signs, newspaper print, stove dials and all the other visual clues that guide you through the day. The low vision clinician uses special charts to measure how well you see both at a distance and up close. Additional vision tests measure contrast sensitivity and locate blurry or distorted areas in the visual field.

You will also be asked specific questions about your vision. Are you affected by glare--outdoors, indoors or both? Do you have difficulty seeing under different lighting conditions? Do you see better on sunny days or cloudy days? How do you describe your ability to see contrast, such as a light gray sweater lying on a white bedspread? Are there any blurred or distorted areas in your vision? Where are they? Do you see better when you look slightly away from the object? Additional questions address your ability to manage activities and tasks of daily living. Expect to discuss with the low vision specialist how your vision impairment impacts your life. Do you travel independently? Can you safely prepare your own meals? What about grocery shopping, making phone calls or taking medications? Can you write checks and manage other financial tasks? How does your vision loss affect your participation in leisure pursuits or in employment-related activities? Do you have any special or unusual hobbies that will need some creative solutions?

The information gathered during a low vision examination enables the doctor to prescribe the device(s) that will best meet your individual needs. Device selection is based on several considerations:

*How strong a lens do you actually need?
*How and where will you use the device?
*With what kind of activity will the device assist?
*Do you need your hands to be free while doing the task?
*Are safety issues involved?
*How big are the items you wish to see? Can the activity be made easier with better lighting, controlling glare or increasing contrast?

A low vision specialist will prescribe devices to maximize your existing vision, but there’s more that can be done. Other vision rehabilitation professionals can offer guidance with activities you may no longer be able to do visually. Alternative, non-visual solutions may need to be learned, while other tasks can, in fact, continue to be done visually with practice and patience. Success with one task can ultimately lead to additional accomplishments, and these positive outcomes may inspire you to achieve even more with your remaining vision. Accepting change is part of the vision rehabilitation process. Often the hardest challenge is adapting to life without vision. The motivation for change increases, however, if making it provides a personally meaningful reward--getting something you really want! This is why it’s so important that the low vision exam addresses the specific needs of each individual. The doctor may guide you to the tools, but you make the tools work.

Few people can be truly prepared for their first low vision visit. The emotional stakes are high, and it’s hard to know if your expectations are realistic. The low vision exam marks the
beginning of a challenging journey. With the proper tools and guidance, plus your own resourcefulness and determination, you can experience successes you didn’t think possible.

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