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Getting the Most Out of Your Low Vision Experience- LOW VISION - THE RULES OF THE GAME
by Tom Perski
For persons who have Macular Degeneration and other eye diseases such as diabetic retinopathy or glaucoma, the low vision process is geared to help with functional vision tasks and aimed at persons who have reduced vision in both eyes. These individuals need help with tasks such as reading small print, writing letters or checks or filling out forms, seeing faces of grandchildren, and for some, help with distant tasks such as reading street signs or even driving.
Because everyone's vision is different, and their visual tasks and needs vary, low vision rehabilitation should be seen as a joint effort between the patient and the professional, and even sometimes a family member or two. It should also be seen as a process because there usually is no "quick fix" or "single pair of glasses" that will do it all. Instead, depending on the severity of the vision loss it may be a ten-step process that will require a lot of patience moving from step 1 to step 2 to step 3 etc. There is no "jumping" from step 1 to step 10. Patients should expect to view their low vision rehabilitation as a slowly improving continuing process that will be with them for the rest of their lives. As people's needs and vision changes, low vision rehabilitation will also change to help adapt and make improvements so that they can maintain as much of their "quality of life" as possible.
Historically, persons were referred to a low vision center when their vision reached the 20/200 level or "legal blindness". Today, those who have a sophistication and understanding of low vision realize that it is far better to refer somebody for low vision services when they have a mild to moderate vision loss in each eye. For instance, if a person's best seeing eye is in the range of 20/50 and they are beginning to have trouble spotting small print type, sometimes education about a good reading task light and a stronger bifocal lens can do the trick for such a patient. Also, a small telescope mounted in a pair of glasses would enable such a patient to easily see street signs at a distance and perform intermediate tasks such as playing cards at the equivalent of 20/20 vision. Then, if vision continues to worsen, this patient may return to the low vision specialist for a "booster session", having already adjusted to using low vision devices and making modifications in their current use of low vision aids.
Unlike medical eye examinations, the low vision process can take many hours of directions and hard work by the patient - not only during the examination, but also afterwards when he or she is "practicing" many times each day following the exam to gain maximum benefit. That is, the patient needs to "take ownership" in this process. "Take ownership" is a phrase we use in psychology. It means you are ready to take responsibility for whatever may be asked of you to get the maximum improvement. Yes, the Doctor may prescribe things for you but you must work together with the Doctor or the low vision professional to come up with solutions that work best for your situation. You cannot "sit back" and expect the Doctor to do it all.
Another misconception about low vision aids is that there is going to be "one pair of glasses" or "one magic device" that will do it all for you. A typical low vision patient may use 5 or 6 different items to help with his or her visual tasks depending on whether he or she is reading small print or large print, reading at home vs. reading in a dark restaurant, or reading a price tag in a store. Other aids may be used to view grandchildren's faces and even high tech items such as CCTV's, computers, and head-borne electronic goggles help make today's low vision patient independent and successful in whatever he or she wishes to accomplish.
There are some rules that govern the use of each low vision device and you must know the rules and educate yourself about them - both the positive gains and the negative side effects. Otherwise, you will not be approaching each device with a realistic expectation of what it can do for you.
When using a hand held magnifying glass, you need to know that these lenses come in different powers or strengths. It is important to keep in mind that as the power of the lens gets stronger, the diameter of the lens gets smaller. Another way to say this is, the larger the lens, the weaker the power will be. Many people ask for a large lens that will cover a wide area, or would cover the entire page - obviously this is not possible because as the lens gets stronger it will get smaller and smaller.
The lens will also have to be held closer to the paper as it gets stronger. Often when persons use very strong lenses, this distance from the paper can become frustrating because if the lens is moved slightly it may go out of focus. It is hard to maintain an equal distance from a piece of paper unless the entire paper is flat and you have a steady hand. This is one of the reasons why a stand magnifier (a magnifier with little legs on it) is often chosen. The legs on the magnifier are preset with the correct focal distance from the paper and the person can easily move this stand magnifier across the paper to read. When using a hand-held magnifier, however, it is important that the person does not look through their bifocal lens to read. When using a stand magnifier, it is important that they look through their bifocal. Yes, there are many rules to the low vision process and sometimes having another family member or friend go with you on an appointment can help "take notes" of these many rules in using low vision aids.
Just to make matters more confusing, magnifiers come in two different types of measurements. The common or layman term, often used in describing the power of the lens, are known as 2x or 3X or 4X. These are commonly known as 2 power, 3 power or 4 power. You may have noticed this when looking through a catalog of low vision devices for these measurements. However, you may also have noticed for the same magnifier a description labeled +8 diopters, +12 diopters or +16 diopters respectively. What does this mean? Why are there two different measurements?
An easy way to remember the true measurement or diopters in a lens is as follows: Multiply the power, for instance 2X by 4 to determine the diopters, in this case equaling +8. 3X would equal +12 diopters, 4X would equal +16 diopters, 5X would equal +20 diopters and so on. When you convert the power of the lens to diopters, you are helping to make an "apples to apples" comparison of all magnification lenses. Some lenses, for instance, may come in a reading half-eye in a power of +6, +8, +10, +12. People mistakenly call these reading glasses 6 power, 8 power, or 10 power, which they are not.
To make things even more confusing lenses manufactured in Europe have had a different standard although there is currently a strong proposal underway to make all lenses, U.S. and European, equivalent. Currently, lenses made in England or Germany such as Coil or Eschenbach brands, use the following formula: the power of the lens multiplied by 4 just as in the US lens, then subtracting 4 from the total. For instance, a 4X lens in US diopters would be +16, in European it would be +12. A 6x magnifier would be +24 in US and +20 in European. Sometimes you may not know where the lens is manufactured so two different 4X magnifiers may be the same or may be much different in strength if you cannot determine the number of diopters.
No matter what lens is selected by the low vision person, it is only as good as the task light that is available to illuminate the printed material. Low vision persons should consider investing in a good quality task light because this type of light will be needed regardless of the optical device they use - now and in the future. When selecting a task light, first determine where you want to sit when doing most of your reading - in your comfortable chair or at a table or desk?
Task lights are characterized by having a swing arm for adjustable gooseneck configuration where a person can pull the light down close to their reading material. Ideally, the light should be placed below eye level to reduce glare, and if using a hand held magnifier, the lamp should be angled so that the light goes between the magnifier and the page and not through the lens. It should also have a hard cover or shade so that the light gets focused only on the task. Additionally, the lamp should be placed over the shoulder of the better seeing eye when reading in a chair or in bed. When reading at a desk or table, avoid having the task light directly in front of you since light will "bounce" off the paper towards your eyes. Try to angle the lamp so the light is coming more from the side, and then bouncing away from you.
For persons who read for a long period of time, you may want to consider using florescent bulbs. Many new high quality lamps offer a combination of several florescent bulbs within one lamp for a full spectrum of light. There are also florescent bulbs that screw into a standard socket. The low heat, full spectrum bulb can emit 100 watts of light, yet only take 15 watts of power. They are low heat, and also rated to last 10,000 hours.
Incandescent bulbs are most popular; however, many people feel that they need a high wattage bulb to do the job. This is not true, and can be a hazard because some lamps are only rated to hold a 60-watt bulb. If a person tries to use a 100-watt bulb, he or she can cause a fire. Just to give you an idea of how strong a 60 watt bulb is when pulled down within 12 inches of your reading material, the illumination on the reading surface would be more than four times stronger than a lamp with a 100 watt bulb and a lamp shade sitting on an end table four feet away. Task lights that use a halogen bulb provide the most illumination, however there is a lot of heat emitted by the bulb, and these task lights usually cause a "hot spot" on the page with uneven illumination.
Many persons say "I'd rather not have to hold something in my hand to read. Isn't there a way to make a stronger bifocal lens or a pair of reading glasses to help?" The answer is yes - but here is where the next rule comes in. Reading lenses, whether in a bifocal or in a pair of low vision reading glasses also come in different powers or strengths - the higher the power or strength of the lens, the closer you must hold the reading material.
Most people have been reading at a comfortable distance of approximately 18 inches for most of their life, now their low vision specialist says that they must use +8 magnifying reading glasses and must hold the reading material 5 inches from their glasses. People exclaim - "If I have to read that close, I am not going to do it!" That is way to close! Unfortunately there are some optical laws of science which are a draw back to using stronger and stronger lenses and this rule in low vision, often called the 40 inch rule, is as follows: the formula 40 inches divided by the power of the lens equals the focal distance you must hold the material. Well let's take an example. If you had been reading with bifocals that were a power of +2.00, you have been reading at a distance of 18 or 20 inches. Now that you have Macular Degeneration or low vision and need a more powerful lens, perhaps a power of +8, you take 40 inches and divide by 8, which gives you a focal distance of 5 inches. Some persons are not able to see regular print even with a power of +8, so they must go to a stronger lens, let's say a power of +10. Now, 40 inches divided by 10 means you must hold the material at 4 inches. Are you getting the idea? Many people also state that when they first try this type of lens, they feel a "pulling" or "tugging" on their eye, which is uncomfortable and unfamiliar. Other people even state that they feel nauseous or it makes their stomach upset because the lens is so strong. Even though this is a common reaction, it is one that must be overcome slowly but surely in order to be a successful user of this type of low vision device. It can be done - no one said it was going to be easy - or maybe you said in your own head (expectations "this will be easy and I will find a lens that will help me read again!") Unfortunately again, low vision is a slow and sometimes difficult process of adjustment and cannot be hurried along. With much patience and forbearance come little steps towards success.
There are also other options that people may choose. For instance maybe using both reading glasses and a hand held magnifier so that the power in the lens does not need to be as strong, so that the reading material can be held farther away, then using a hand held magnifier for smaller print types when needed. For persons with a severe vision impairment who need lenses that are very strong, they may have to have a special lens made in a pair of glasses which range in the power of + 20 to +40. These types of lenses, only available through low vision Doctors, have a very close working distance of 1 to 2 inches from the eyes. There are also some new telephoto reading glasses which allow a person to read at a distance of 3 inches instead of at 1 or 1 1/2 inches, yet these type of lenses take a lot of patience and training in their proper use. Many people who find themselves in this category often choose to also look toward electronic magnification such as a closed circuit television reading machine (CCTV) to help read printed material and to write letters, checks or forms. The advantage of using a closed circuit television reading machine is that a person can sit comfortably, at a working distance of 12 inches to 16 inches, with much stronger powers than available in an optical lens. These systems, which project reading material onto a TV screen or monitor, can go from 3 X to 45 X or sometimes 60 X so that a person can take a phone book, for instance, and place the book on the tray and see the letters on the screen at one inch high or five inches high depending on how they turn the dial. The letters can also be viewed with much more contrast, using white letters on a black background or black letters on a white background, and some new machines also have different color combinations which are easier to detect for some. Obviously, you cannot bring this type of equipment with you to the grocery store or the restaurant, so most low vision persons even if they are using a CCTV reading machine also have several other optical tools in their "tool box" to help them read a price tag in the store or a menu in a restaurant. Many of these items are specialty items such as a magnifying glass with a built in light, just for this type of situation.
For persons with Macular Degeneration, there may not be any distant prescription glasses or contact lenses that would improve vision acuity. So, how can a person improve their distance viewing? Either by getting closer to the objects they want to see, or by using some type of telescopic lens. There are many varieties of telescope lenses available through low vision centers and low vision catalogs, but if you have never used a telescope before there are some things you should keep in mind. Telescopes also come in different powers or strengths, for instance many persons may start at 3X or 4X (referred to as 3 power or 4 power). 6X, 8X, and 10X powers are also available.
A telescope by its characteristics is always a two-lens system. That is the lens that you look through is the lens closest to your eye, the second lens is the lens that is furthest from your eye, or "sticking out" near the front of the telescope. As the telescope power or strength gets stronger, the area or field of view gets smaller. So, with stronger lenses smaller details can be seen, yet the trade off is a smaller viewing area. This is a very important rule when considering using a telescope because again like a magnifying glass, he or she may be frustrated at only seeing a small area at one time and reject using a telescope.
There are so many varieties of telescopes in the low vision market today. Some of them are hand-held telescopes that are quite small, maybe 1 1/2 inches to 2 inches long, and can be carried in a pocket or purse or worn around your neck on a strap like a whistle. Some of these type of hand-held telescopes can also be mounted into a pair of glasses so that the person, with help from a professional, can utilize the scope in their best seeing eye (that means they would only use the telescope for one eye) and have the scope drilled through the lens of the glasses so that the telescope does not have to be held in the hand, but can be worn on a pair of glasses for TV viewing or other types of viewing for a longer period of time. There are also other companies who make monoculars or binoculars (one or two eyed telescopes) that you can wear like a pair of glasses for viewing distant objects.
Probably the greatest request for these type of systems is for watching TV; however, some persons are frustrated by the small field of view and often cannot see the entire TV screen at one time when using this type of telescope, especially in the stronger powers. Some use telescopes very well however and with proper training and guidance, it can be a very important tool in your low vision toolbox. Other uses for telescopes include seeing the blackboard in school, the minister's face at church, viewing a movie or slides, seeing a street sign or bus sign, the clock on the wall, and yes there are special telescopes for driving! These lenses called bioptic telescopes are mounted in a pair of glasses especially made for this purpose and are allowed in several states in the U.S.
Probably the hardest low vision visual task to help someone attain in low vision is the intermediate distances such as seeing music on a music stand, playing cards where a person needs to see the cards laid out on the table, or other tasks such as seeing the computer screen or the keyboard. There are special reading telescopes that allow a person to do some of these tasks; however, the rule here also applies as in distance telescopes that the stronger the telescope, the smaller the viewing area. Many persons stated that even though they could see one note at a time on their music sheet, it is too difficult to use to move along and follow a line of music. Also, as in distant telescopes, whenever the distance from the object that you are looking at changes, you must stop and refocus the telescope. This also can sometimes be frustrating if you're looking at objects at different distances. Some distance telescopes also can be used as intermediate telescopes simply by turning the outer lens to create this short focal distance. Many people have success in using a telescope for such tasks as seeing through a glass case in a museum for instance or being able to see fish in an aquarium or small animals or vegetation in a terrarium. One low vision person told me she could read the Declaration of Independence which had a 6 inch glass in front of it on display in Washington D.C., by using her telescope, when otherwise she was not able to get close enough to the document to read it.
There has also been a lot of enthusiasm about the new Occutech Auto-Focus telescopic system, recently seen on CNN, which can be mounted on a pair of glasses. This lens system which is used for one eye and comes currently in a power of 4X automatically focuses for reading, intermediate, and distant tasks which takes away some of the frustration of constantly having to refocus the telescope.
Finally, there are a few new high tech video magnification devices that can be worn like glasses, or a camera system to help see even better than telescopes. These systems, one called Jordy and another called Flipper Port, allow a person to see TV, and many distant objects. The advantages of these systems are that the level of magnification can be changed, from small to large to very large, with the click of a switch. Hopefully, more innovative products like these will continue to be introduced in the future, as these low vision aids can help to make the low vision person more independence, bring a new quality of life, and allow a person to be as independent as he or she wants to be.
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