“As the population ages, we need to be in a position to help more low-vision patients,” said Douglas R. Williams, OD, FAAO, associate professor of low-vision rehabilitation services at the Southern California College of Optometry. “These patients want to interact with others, work, perform daily activities, travel and lead active and full lives.”

One important facet of low-vision care is technological innovation. In an effort to keep in step with this phenomenon, many companies have been steadily launching new products. Both optical and non-optical devices are being redesigned for comfort, portability and ease of use.

“It is a combination of new things and the redeployment of old things,” said Roy G. Cole, OD, FAAO, director of vision program development at the Jewish Guild for the Blind in New York and in private practice in Brooklyn, N.Y. “To a large extent, it’s just a redesign and a reissuing of things we have had all along. But there are some new and exciting developments in the works.”

Optical advances

Although innovations in non-optical technology currently figure prominently in low-vision correction, traditional optical devices are also being redesigned and improved. “I think there will always be a real place for the optical,” Dr. Cole said. “I have concerns about going strictly toward ‘electro-optical,’ because optical devices are still a good option for patients.”

Among the recent innovations in optical devices are customized prism glasses, launched by Chadwick Optical Inc. These glasses are based on a new design for a prism conceived by Eli Peli MSc, OD, FAAO, associate professor of ophthalmology at Harvard Medical School and senior scientist at Schepens Eye Research Institute.

This special prism lens is used to expand the view for patients suffering from hemianopia, a common condition in stroke patients and those suffering from traumatic brain injury.

Chadwick Optical has devised technology to replace two other prism lenses that were previously available. The Channel Lenses used for tunnel vision (concentric peripheral field constriction) and the Half-Prism used for hemianopia are now being produced. Chadwick is also fabricating Variable Tints in plastic with wavelength cutoffs of 450, 480, 500, 540 and 550 and other glare-reducing and contrast enhancement filters in a wide variety of lens styles. Polycarbonates are available in single vision. These tints offer true transmissions and have been found useful for managing glare and contrast enhancement.

“They are allowing us to design some specialized lenses for patients that were very difficult to find for a while,” Dr. Cole said.

LED illumination in magnifiers

Another category of low-vision correction is that of magnifiers, which are available in hand-held and stand varieties. Many manufacturers are introducing light emitting diode (LED) illumination to their lines of magnifiers.

Eschenbach, COIL and Schweizer currently have LED illumination systems in many of their magnifiers and are expanding their product lines to include this type of illumination. Eschenbach offers a yellow filter that can fit over the LED bulbs for a softer yellow-color light. With the introduction of the LED illumination, the choices for illumination systems now include LED, halogen and incandescent.

“LED illumination provides a softer, longer-lasting source of illumination,” Dr. Williams said. “The estimated life of the LED bulbs is almost unlimited, to the point where many manufacturers claim the bulbs never have to be replaced. This type of illumination also draws less power. Thus, battery life is extended, making frequent replacement of the battery a less troublesome feature.”

Among the magnifiers to use LED illumination is the Videolupe (Eschenbach), which was introduced in 2001. This combined optical and electronic product uses a 3× (7.6 D) stand magnifier lens and a 9× to 17.5× video magnification (depending upon the size of the display monitor). The Videolupe connects to any television and requires no focusing. This device allows the patient to orient himself or herself by looking through the lens first before viewing the magnified text on the display monitor TV screen.

Video telescope

The VisAble VideoTelescope (Betacom) is a lightweight, hand-held, video-based low-vision aid developed to provide mobile vision enhancement capabilities for all daily living tasks —indoors and outdoors. The VVT300 can focus from near to infinity with unique contrast stretch image-enhancement capabilities to assist low-vision patients with a variety of conditions including macular degeneration, diabetic retinopathy, retinitis pigmentosa, glaucoma and cataracts in all lighting conditions, regardless of vision task. The unit is a monocular device that has the appearance of a hand-held video digital camera.

The magnification is approximately 40× (10× optical combined with 4× digital) in a variable (zoom) auto focus. There is also a –2× minification, which provides for a compressed image within an extensive field of view. The image is provided via a rectangular (35° × 27°) screen that delivers more than three times the field of conventional 12.5° optical monoculars of similar power. The VVT300 screen uses a very high-resolution (800 × 600 pixel) display that provides SVGA image quality. The device was developed with the research partners of the University of Waterloo Centre for Sight Enhancement, Johns Hopkins University Wilmer Eye Institute and the Ontario Rehabilitation Technology Consortium.

Binocular telescope

Through a grant from the National Institutes of Health, Ocutech Inc. is developing a binocular autofocus telescope for low-vision patients. The binocular system is being designed to allow magnified and binocular vision at far and near distances. Already available is the manual focus VES telescopic system and the VES-Auto Focus (AF) bioptic telescope, both monocular telescopic systems. The VES Auto Focus (AF), introduced in 1996, is a miniature Keplerian telescope available in 3× , 4× and 6× powers that is designed to help patients see at distance as well as near, including computer screens.

“The VES Autofocus (AF) has solved the problem of refocusing with slight movements and shifting view from one object to another,” Dr. Williams said. “The Ocutech VES-AF provides immediately and continuously clear magnified vision from 12" to infinity.”

Electronic low-vision devices

Since the commercial introduction of closed-circuit television in the 1960s, the field of electronic low-vision devices has advanced so rapidly that it is difficult to keep up with all the latest technological innovations. Emphasis has been on higher resolution cameras, color systems, portable systems and headborne lightweight LCD (liquid crystal display) screens.

One such device is the MiniViewer by Telesensory. The MiniViewer has three magnification levels (5×, 10× and 15×) that are displayed on a portable 5¾" LCD color display. It has a color or black-and-white display and a positive or negative polarity display option. It is truly portable, weighing 1.76 lb., and is available with both plug-in or rechargeable battery options.

Enhanced Vision Systems Inc. introduced the Jordy (joint optical reflective display) in 1999 and has now updated the original model with the Jordy 2.0.

“The Jordy uses two LCD screens located in a lightweight headpiece,” Dr. Williams said. “The camera in Jordy 2.0 is located in the headpiece at eye level, allowing easy positioning for reading. The device allows for distance, intermediate and near viewing and uses a 1-30× autofocus magnification.”

The device features full-color, positive or negative contrast and a 44° field of view. The unit weighs 8 oz. and is battery operated with controls. The Jordy can also be converted as a CCTV by using its patented docking stand.

Another instrument, the NuVision, by Keeler Instruments Inc., uses two LCD screens that position in front of the eyes and allow magnification up to 5× in the distance and up to 10× at near. Image enhancement as well as different color and contrast settings is available. The unit weighs 6 oz. and is powered by a regular 110-volt current or a lithium battery that lasts up to 2 hours.

Retinal scanning display

Telesensory has partnered with Microvision to investigate retinal scanning display (RSD) technology for its application to people who suffer from low vision. Developed by Microvision Inc., the Nomad is a wearable, head mount display that uses RSD technology to paint an image directly onto the retina.

The device scans a beam of light to “paint” rows of pixels directly onto the retina, creating a high-resolution, full-motion picture without the use of an electronic screen. To the viewer, this image appears to be at arm’s length away, as if on a large-screen video monitor. In reality, the image is projected onto the viewer’s eye— not a screen. The resolution is 800 × 600, with a luminance of 1 to 800 foot-lamberts. The field of view is 27° x 20° (equivalent to a 19” monitor at arm’s length).

Telesensory concluded its clinical trial with the Nomad technology in December 2001. Results from the study at the VA Palo Alto have shown that this technology not only enables people with low vision to read and write again, but it also aids those who suffer from severe low vision.

“You could call the Nomad electro-optical,” Dr. Cole said. “However, all of the other systems create an optical image that the eye is looking at, but the Nomad uses a laser and actually paints an image onto the retina. Just like when you go to see a laser show, what you are seeing is one laser beam that is being moved rapidly. It is creating a whole picture.”

Dr. Cole said he believes the Nomad shows promise for the future of low-vision correction. “The Nomad is something that could potentially be very effective, depending on how it plays out,” he said. “Studies have shown that in some ways, it is better than traditional devices, and in some ways it isn’t. But I think that in terms of where we are going, this is one area that is very exciting.”

For Your Information:

• Douglas R. Williams, OD, FAAO, can be reached at 6042 Warner Ave., Huntington Beach, CA 92647; (714) 847-6059. Dr. Williams has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Roy G. Cole, OD, FAAO, can be reached at the Jewish Guild for the Blind, 15 West 65th St., New York, NY 10023; (212) 769-6316; fax: (212) 760-4193. Dr. Cole has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• William L. Park, OD, FAAO, can be reached at Lions Vision Research, 600 N. Wolfe St., B1-70, Baltimore, MD 21287; (410) 955-0580; (410) 817-9504.

• Chadwick Optical, which makes customized prism lenses, can be reached at PO Box 485, White River Jct., VT 05001; (800) 410-1618; fax: (800) 468-9301; e-mail: chadwickoptical@aol.com.
• Eschenbach, manufacturer of the Videolupe, can be reached at 904 Ethan Allen Pkwy., Ridgefield, CT 06877; (203) 438-7471; (800) 487-5389; fax: (203) 438-1670; Web site: www.eschenbach.com.
• Betacom, maker of the VisAble Video Telescope, can be reached at 450 Matheson Blvd. E., Mississauga, Ontario L4Z 1R5 (905) 568-9977; (800) 353-1107; fax: (905) 568-9925; Web site: www.betacom.com.
• Ocutech, maker of the VES-Auto Focus bioptic telescope, can be reached at 109 Conner Dr., Suite 2105, Chapel Hill, NC 27514; (919) 967-6460; (800) 326- 6460; fax: (919) 967-8146; Web site: www.ocutech.com.
• Telesensory Corp., manufacturer of the MiniViewer and the Nomad, can be reached at 520 Almanor Ave., Sunnyvale, CA 94085; (408) 616-8700 ext. 3243; fax: (408) 616-8719; e-mail: info@telesensory.com; Web site: www.telesensory.com.
• Enhanced Vision Systems, manufacturer of the Jordy, can be reached at 17911 Sampson Lane, Huntington Beach, CA 92647; (800) 440-9476; fax: (714) 374-1821; Web site: www.enhancedvision.com.
• Keeler Instruments Inc., manufacturer of NuVision, can be reached at 456 Parkway, Broomall, PA 19008; (610) 353-4350; (800) 523-5620; fax: (610) 353-7814; Web site: www.keelerusa.com.

Stay connected - Sign up for the PCON e-mail news wire!

Copyright ® 2010 SLACK Incorporated. All rights reserved.