Product knowledge in every field is important, especially regarding our patients who have vision loss. These patients generally are frustrated and anxious, and they often have a real fear for their future. Too many times they have heard, “There is nothing more that can be done.” Yet, often times, there is.
Low vision is about helping the person do those functional tasks that are important to them. As a low vision specialist, I have found this list of functional tasks most frequently includes reading, writing, recognizing faces, and driving.
This article presents an overview of the devices that can help those who have vision loss, categorized according to the distances those tasks require. Since most of vision loss patients require magnification, this article is limited to conditions that cause central vision loss, such as age-related macular degeneration, Stargardt disease, and Albinism.
NEAR TASK HELP
To assist with near tasks, plus lenses provide magnification due to the closer working distance. As the amount of plus increases, the aberrations also increase, so we need different forms of plus lenses to select the best solution for our patients. Devices that help with near tasks include:
- Prismatic glasses. Ready-made prismatic glasses help patients who need less than 12 D of plus and are binocular. Usually half-eye frames, the plus powers are married to the prism power, so no calculations are necessary. Manufacturers can provide a kit, which includes a number of powers, that can be kept in the office.
- Microscopic glasses. Above 12 D requires aberration control, and we call them microscope lenses. There are three forms of these lenses: aspheric, lenticular, and aplanatic. Aplanatic are doublet lenses piggy-backed for best optics. They are prescribed monocularly. Doublet microscope lenses can be ordered in powers up to 80 D. I fitted a patient who flew in from Peru with a 14x (+56 D) microscope for reading. After receiving her new glasses, she held the material up to her nose, read the newspaper, and began crying with joy.
- High-add bifocals. Many seem to think that a +3.00 add is the highest possible, yet there are microscope bifocals that range in power up to 40 D. Also, a good optical lab can produce a cemented executive bifocal that contains virtually any add power.
- Reading telescopes. These can be focused for any distance the patient requires. They can be prescription or OTC. Their benefit is magnification at any distance required by the patient’s task. The disadvantage is the limited depth of focus and the reduced field of view.
- Hand/stand magnifiers. These devices work well for the spot reading of items, such as price tags, oven dials, food labels, restaurant menus, etc. They are not recommended for continuous reading of items, such as books or newspapers, as they would require the user to move the device constantly. For proper prescription for these devices, remember the following:
- Hand magnifiers. The patient is to use the distance prescription in their glasses.
- Stand magnifiers. The patient is to use the near prescription in their glasses.
- Electronic magnifiers. Offering variable magnification and contrast, these devices work well depending on the task. Because continuous reading, spot reading, and writing are different tasks, a “task analysis” is always necessary when prescribing a low vision device.Electronic magnifiers are available as handheld, desktop, and head-borne devices. Also, magnification apps, such as BigMagnify (OIS) and Magnifying Glass (Android), can be downloaded onto smartphones.
Reading telescopes (top and above) can be focused for any distance the patient requires.
Smart device apps (above) offer features, such as magnification and audio.
Practicing the Standard of Care
According to the American Academy of Ophthalmology, “Provision of, or referral to, vision rehabilitation is now the standard of care for all who experience vision loss” (see aao.org/lowvision-and-vision-rehab ). Further, the American Optometric Association notes, “Without a proper referral and a visual efficiency and function evaluation, patients who have uncorrectable vision impairments may never receive the vision rehabilitation services they need to maximize health, quality of life and independence” (seeaoa.org/practice/specialties/vision-rehabilitation?sso=y ).
If you are unsure of whether a low vision referral is appropriate, ask the patient one question:
Has your vision loss caused you to give up any activities that are important to you? A “yes” answer indicates the patient likely will benefit from a low vision referral.
INTERMEDIATE TASK HELP
Reading music at the piano, seeing playing cards on the table, and using the computer are all examples of intermediate tasks.
To aid with intermediate tasks, the aforementioned reading telescopes can be focused for any distance and have various levels of magnification and field of view.
For the computer, reading telescopes are one possibility. Software programs (i.e., Zoomtext, Jaws, etc.), which give the user the ability to change text size, contrast and add audio, can be an effective solution. Also, many free screen reader applications, such as VoiceOver (OIS) and NVDA (Android), are available.
In addition, apps are available to provide assistance with daily tasks and activities, including learning, occupations, shopping, travel, object identification, and more. (For an introduction to a variety of low vision apps, see “Apps for People With Vision Loss,” in the April 2022 issue of Optometric Management at bit.ly/OM2204LowVision ).
Low Vision Resources
There is a tremendous unmet need in the field of low vision care. By searching “low vision residencies,” you will find many programs available for learning low vision. Several additional resources are available, for example:
→ The American Academy of Optometry Low Vision Section. The section “was established to foster excellence in patient care and professional development in the American Academy of Optometry in the area of low vision rehabilitation through fellowship and leadership in education and research.” Visit the Academy’s website (aaopt.org ) for information.
→ The American Optometric Association Low Vision and Vision Rehabilitation web page provides resources for patients and optometrists on all vision-rehabilitation services, including information on referrals, low vision services, and more. Also included is a section on the low vision consultation. Visit the AOA website (aoa.org ) for information.
→ The International Academy of Low Vision Specialists “is committed to the realization that there is life after vision loss.” Designed for ODs in private practice, members receive advanced training in prescribing specialized glasses to help low vision patients regain their independence. For more information, visit ialvs.com .
DISTANCE TASK HELP
Consider the following devices for those low vision patients who require help with distance tasks:
- Bioptic telescope glasses. These glasses incorporate a miniature telescope of various powers and designs to allow a patient to have magnification at a distance. They can be monocular or binocular, fixed focus or focusable, and auto-focusable.
- Handheld monoculars. These provide an inexpensive solution for those needing just a rapid look at a distance object, sign, or face. They are available in many powers, and most are focusable.
- Head-borne electronic magnification. These systems are an exciting development. Manufacturers are working to perfect these devices, which deliver various levels of magnification, contrast enhancement, portability and hands-free use.
THERE’S MUCH MORE
This is by no means a complete list of all aids available for patients who have visual impairments. The products displayed are simply examples, and not meant as recommendations for any particular device. We all, of course, have our own personal preferences regarding products, whether they are contact lenses, frames, or optometric equipment.
The key point to remember from this article is that low vision care is more about improving or restoring function than it is about assessing visual acuity or visual field. And providing your patient with or referring them for low vision care will make a huge difference over saying “nothing more can be done.” OM
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