Low Vision Aids
Chat Highlights
September 6, 2006

On Wednesday, September 6, 2006, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Low Vision Aids."

Moderator:   Welcome back to chat, Dr. Wilson.  The topic tonight is low-vision aids.  First, what does low vision mean?

Dr. Rick Wilson:  To me, low vision means having vision that is not corrected to a functional level by normal glasses.

P:  Are there low-vision aids particularly designed for glaucoma patients?

Dr. Rick Wilson:  Patients with glaucoma lose the vision around their central vision, especially on the nasal side. The central vision is lost only in very advanced cases.  Therefore, patients with advanced glaucoma, without cataract or macular disease, can often see quite well at distance and near.  Their main problem may be having such a narrow field of vision that walking is difficult. They have to scan with their eyes as they move so as to avoid running into things or tripping over objects.  Therefore, glaucoma patients are often not helped by low-vision aids unless there is another problem reducing their central vision.

P:   I think that stretching the visual field optically, narrowing it, is possible.  I remember that when I was myopic and looked through the inverse side of my glasses, people looked smaller and slimmer.

Dr. Rick Wilson:  I think that “stretching” the visual field just magnifies the image of that field without perceiving a wider cone of light coming into the eye.

P:  What type of patient benefits most from low-vision aids?

Dr. Rick Wilson:  Low-vision aids are much more helpful for patients with a disturbance in their central vision, macular degeneration, or other retinal disease.  Enlarging the image of what they are trying to see may allow the remaining retina to discern it.  Patients with macular degeneration often have to learn to use the retina to the side of the lost central vision.  That may require significant magnification.

P:  Does that mean glaucoma patients do not need low-vision aids?

Dr. Rick Wilson:  Most glaucoma patients with healthy retinas and no cataracts usually can manage without low-vision aids.

P:  Would using a cane to sweep in front of their feet be useful to glaucoma patients?

Dr. Rick Wilson:  If their central island of vision were extremely small, a cane would help them avoid tripping on objects beneath their vision and could also help steady them.

P:  Since glaucoma seems to decrease contrast sensitivity, is good lighting considered to be a low-vision aid?

Dr. Rick Wilson:  Yes.  Glaucoma patients do well with black letters on a white background, but poorly with gray on gray.  For instance, imagine a concrete curb at the edge of a concrete street on a cloudy day.

P:  What are some examples of visual aids?

Dr. Rick Wilson:  Most often a low-vision aid is used for reading. A very strong lens is placed in front of one eye only.  If the lens were placed in front of both eyes, the material would be too close for both eyes to focus on.  With the lens in front of one eye, the material can be brought quite close.  Therefore, the image on the retina is much larger than normal, and the patient may be able to see it.

A more technical low-vision aid is a small telescope that fits into eyeglasses to enlarge a small field.

A common and helpful low-vision aid is the closed-circuit television that images a book on a movable platform, and magnifies the image many times on a video screen (monitor).

P:   Someone in this group suggested using a video cam to enlarge print and project it onto your TV or computer screen.  I use that for long newspaper articles.  It works well.  You can use an inexpensive cookbook holder to hold books, newspapers, and magazines.

P:  Don't many glaucoma patients complain of problems with their vision, even when their acuity isn't bad?

Dr. Rick Wilson:  Yes, they often mistake the gray or black areas in their vision as poor focusing of their lenses, instead of lost retina not recording any image.

P:  Are there any special aids to help glaucoma patients who are aphakic or legally blind?

Dr. Rick Wilson:  Aids may be more useful for someone who is aphakic (no natural or artificial lens in the eye), as the added power needed can be included in the aid.

P:  Does a doctor have to prescribe these aids?

Dr. Rick Wilson:  Usually, a low-vision expert, often an optometrist, will test the patient to see which aid would be best.  Often, a special magnifying glass, sometimes with its own lighting, may be all that is required.  A low-vision center will have a variety of aids to show the patient and allow an informed selection.

P:  Today I saw a woman, who was pushing a shopping cart, wearing a yellow pin with large black print, which said: “I HAVE LOW VISION." Do you think she was wearing the pin because it made her feel safer?

Dr. Rick Wilson:  The pin may have the same function as a white cane, that is, to inform others around her that she has a problem and people may be sympathetic, if not helpful.

P:  Here in Australia some people wear badges with “VIP” on them.  Many people here do not know that “VIP” means “Visually Impaired Person.”

Dr. Rick Wilson:  Here it would mean “Very Important Person.”

P:  Is balance a problem with low vision?

Dr. Rick Wilson:  Tripping is a problem with low vision, but balance usually is not.  Many older patients have trouble with circulation to their middle ear or cerebellum, which may cause vertigo or dizziness. If they have diminished vision, they may blame their problem on glaucoma and miss the underlying problem.

P:  Does wearing a colored lens help?  I read something about an amber lens helping with contrast sensitivity.

Dr. Rick Wilson:  Yes, hunters and skeet or trap shooters often use an amber lens to increase contrast.  I have often had patients who complain about decreased vision on cloudy days and try an amber lens.  NOIR (a company whose name stands for No Infra Red) has inexpensive clip-on lenses in many shades that can be tried. Corning Glass has expensive lenses that do the same thing, but the corrective glasses can be made of the lenses.  Unfortunately, only about one in three patients finds the amber lenses help.

Moderator:   My favorites are clip-ons.

Dr. Rick Wilson:  I use them, too. They are much less expensive than bifocal sunglasses.  Also, if you are light sensitive, an optician can get the sunglasses in all shades.  They usually have blanks of the middle-light blocking strengths.  For bright days, or when there’s sun, snow, and sand on roads, I usually opt for a much darker lens that blocks 80 to 90 percent of transmission.   Clearly, those would not be good for someone with decreased contrast sensitivity, but might help a patient with a large pupil after an acute-glaucoma attack or surgical dilation of the pupil.

P:  Are polarized lens useful for low vision?

Dr. Rick Wilson:  Recently, I had a patient raving about polarizing lenses to reduce glare.  I recommend that my patients see a good optician who has many blanks of different sunglass strengths and kinds.  It’s best to try out the lenses on a bright, sunny day before buying to make sure they suit your needs.

P:  For those who are legally blind or worse, the library has talking books.

P:  Talking books are wonderful.  Our local library has a large selection large-print books and books on tape or compact disk. Most optometrists now carry a range of "low-vision aids."

Dr. Rick Wilson:  Many agencies for the blind and partially sighted also have a radio station.  Listeners can tune in to that frequency to hear someone read the daily newspaper, books, and magazines.

P:  Do most communities offer services for people with low vision?

Dr. Rick Wilson:  Many larger communities do.  The Neville Institute, which is almost across the street from Wills Eye Institute, provides a full range of help to patients with limited or no vision.  Many of the surrounding counties also have agencies.

P:  My husband gets the local newspaper on a tape cassette every week.  The local vision support groups help by sharing ideas.  Ours has a collection of low-vision aids, donated by people who can no longer use them, so that other people with low vision can try before buying their own.

Dr. Rick Wilson:  The New York Times has a large print edition that is wonderful.  I read it every week before putting it out in my waiting room.

P:  A great device that has saved many burned fingers clips onto the side of a container and beeps when the container is full.   There are so many aids out there.  For instance, my husband could tell you the denominations of money in his wallet and how to fold them so that you can tell the difference quickly.  He has special coin holders for $1 and $2 coins, talking tape measures, noise-activated levels, and more.

P:  You also can buy colored dots to mark your oven settings, microwave oven, dishwasher, and other appliances if you have difficulty seeing the dials.  A talking calculator comes in handy, too.

P:  Talking watches and clocks are useful, too.

P:  Dr. Wilson, before you leave I want you to know that I’ll be thinking about you during your surgery. Have a quick recovery and thanks for being here for all of us.

P:  Yes, you’re terrific, Dr. Rick Wilson. Thank you so much.

P:  We'll certainly miss you, Dr. Rick Wilson. Take good care of yourself, and many thanks for giving so generously of your time to so many.

Moderator: Thank you, Dr Rick. Unfortunately, we don’t have time for everyone’s comments, so best wishes from all of us for a speedy recovery.

Dr. Rick Wilson:  The next time I'm here, I'll have new knees. Thanks, everyone, for your good wishes.  Good night.

On September 20, Dr. Pro discussed "The Routine Eye Exam" in the Chat room. Click here for highlights of that meeting.

Click here for the most recent glaucoma chat highlights and links to the chat archives.

Click here for upcoming glaucoma chat events.