BRUSHING UP ON YOUR LOW VISION KNOWLEDGE

0
—
The Optelec PowerMag+ HaloBright SMD LED Magnifiers are equipped with SMD LED light which provides a very bright, evenly dispersed and high-contrast light.
—
Tech Optic’s Task-Vision LED Stand Magnifiers feature deluxe anti-reflective blue coating for superior optics.
—
Eschenbach Mobilux 1511 LED handheld magnifier includes a comfortable, ergonomic handle and a distortion-free lens.

You can help patients with low vision issues without being a low vision specialist.

With an aging patient population and the need for more eyecare providers to offer low vision services, there is enormous potential to make this category a specialty within your practice. For many of us who haven’t done a low vision exam since school, the stumbling block remains: Where do you start?

The purpose of a low vision evaluation is to determine if a patient’s current vision can be improved to do the things they need to do. The essential parts of this exam are fairly basic and the equipment most likely in your office already, namely a phoroptor and trial lens set, a retinoscope, a keratometer, a distance Snellen acuity chart, a near Snellen equivalent acuity reading card, an amsler grid, a contrast sensitivity chart, and a simple color vision test.

GETTING STARTED
Your knowledge of a few essential formulas and tips can help patients choose appropriate devices best suited to their needs. Two quick ways to estimate magnification a patient will need (this first method works for both distance and near vision):

  • Divide the patient’s present visual acuity by the required visual acuity. For example: M = what patient can see/what patient wants to see. If a patient’s distance acuity is 6/36 and they want to see 6/9, then 4x magnification should be appropriate. Likewise, if the near acuity is N48 and the patient wants to read N8, then 6x magnification is needed.
  • An alternative method is to increase the reading power (and decrease the working distance) until the person can read.

The most common low vision devices are stand or handheld magnifiers, clip-on magnifying loops, high magnification spectacle lenses, electronic magnification devices, and spectacle or handheld telescopes.

HANDHELD MAGNIFIERS
Ideal for short-term spotting tasks like looking at prescription bottles, price tags, or menus, many of the newer illuminated handheld magnifiers feature LED illumination. SMD LED (surface-mounted design light-emitting diode) illumination provides an alternative light source preferred by many patients due to its distinctly whiter spectrum and longer useful life in addition to the bulbs offering nearly unlimited life (10,000 hours).

Eschenbach Optik of America, Inc.’s 1511 Mobilux series of illuminated handheld magnifiers is one example. To soften the color of the light if needed, small yellow filters are included which can be snapped-on over the LED bulbs to provide an illumination option. The 1511 Mobilux includes an ergonomic handle and a distortion-free lens that has a patented lens coating that makes it nearly glass hard.

Also within this category are Tech Optics’ Task-Visionâ„¢ LED Hand Magnifiers. They feature newly designed aspheric lenses with deluxe anti-reflective blue coating for superior optics and have flicker-free illumination.

Optelec US Inc.’s PowerMag+ HaloBright SMD LED Magnifiers are equipped with SMD LED light which provides a very bright, evenly dispersed, and high-contrast light. The acrylic glass magnifying lens is lightweight and scratch-resistant and provides a sharply defined image further enhanced by the SMD LED lighting.

STAND MAGNIFIERS
For those patients looking for assistance with extended near tasks such as reading a book, signing checks, and doing crossword puzzles, stand magnifiers are a good option. Some are available with or without illumination; the illumination options include LED, halogen, and incandescent.

As a leader in the field, Eschenbach offers a wide selection of stand magnifiers. These include standard Head & Handle combinations, Bar and Bright Field magnifiers, Lamp and Gooseneck stand magnifiers, Pendant magnifiers, and an around-the-neck magnifier which can be used for sewing, knitting, or other hobbies when hands need to be free. One of the most popular is the Makrolux magnifier that looks like a slice of a dome magnifier. It comes in two powers (2.8x and 3.6x), provides a wide field of view (it magnifiers an entire newspaper column), is tilted toward the user (providing ergonomic comfort), and uses bright SMD LED illumination. Within this category you’ll also find:

Task-Vision LED Stand Magnifiers: Newly designed aspheric lenses with deluxe anti-reflective blue coating for superior optics, these products feature a large raised switch which is easier to use, especially for arthritic fingers.

PowerMag+TM Stand Magnifiers: Features three different illuminations: HaloBright SMD, LED Bright White LED, and Contrast Yellow LED.

COIL Stand Magnifier: Offers three bulb options: Incandescent Raylite 1- Tungsten Bulb; Xenon Raylite 2-Xenon bright bulb; LED Raylite 3-LED illumination.

TELESCOPES
For assistance with task distances and any task duration, telescopic vision aids are perfect. Of particular note is the Optelec 2.5X PowerScope Clip-On Monocular Telescope, a hands-free monocular which clips directly to a spectacle frame. The monocular is exceptionally bright and features a fully coated achromatic 25mm objective lens mounted in a lightweight aluminum body. Task-Vision also has a sports telescope that helps with distance viewing.

Another option is Designs for Vision, Inc.’s full diameter telescope. Mounted in a plastic carrier lens, this lightweight system is easily worn. While generally used for distance tasks, it may be converted into an aid with increased versatility by applying a reading cap over the front end of the telescope. The reading cap will focus the telescope for any desired working distance (intermediate or near), based on the power (focal length) of the cap.

The MaxTV line from Eschenbach is another alternative. This lightweight and simple product provides 2x magnification and is ideal for watching television.

HANDHELD VIDEO MAGNIFIERS
A higher technology option for many tasks is handheld video magnifiers. These are similar to stand magnifiers in that they generally have to stand on, or rest against, the reading material in order to work, but they can also just be held in the hand. They offer a distinct advantage over the other categories of low vision devices in that they allow the user to manipulate the image being viewed. Users can change the color of the text and background, take snapshots of the image, and in some cases, add an underline or shutter to help in staying on track while reading.

Handheld video magnifiers generally have a small integrated display that the image appears on. There are also ones that can project magnified images on a television. Some of the portable video products that are available include Optelec’s Compact Touch HD Plus, Task-Vision Digital One, and Eschenbach’s SmartLux Digital.

Keep in mind the devices you first choose for a patient may not work once she’s had a chance to take them home and live with them. It’s also possible a device may be too difficult to learn to use. Tackling low vision requires a lot of practice and patience but in the end, it’s a very rewarding feeling and one that makes brushing up on your knowledge about this aspect of optometry well worth every challenge.

Eric L. Bran, Professional Editor of Optometric Office, is in a private group practice in Ridgefield, CT.

WHERE TO FIND IT:

Designs for Vision •800-345-4009 •DesignsForVision.com

Eschenbach Optik of America, Inc. •800-487-5389 •eschenbach.com

Tech Optics International •800-678-0002 •techopticsinternational.com

Optelec US, Inc. •800-826-4200 •ShopLowVision.com

Share.

Leave A Reply