Ryan M. Byer, O.D., Laura A. Vasilakos, O.D., Barbara S. Cohn, O.D., Yaacov G. Zacks, O.D., and Michael W. Henderson, O.D.
Various ocular and systemic conditions may result in a patient requiring low vision aids and/or training in order to function on a daily basisand sometimes, the best solution isnt immediately apparent. Patients may not know how to explain their symptoms, and without really listening to them, the managing clinician might misunderstand or misdiagnose the condition.
Here, four cases demonstrate what solutions are available for those patients and clinicians who are willing to work together until the most fitting low vision solution is found.
Case 1: Diabetes
Ryan M. Byer, O.D., Laura A. Vasilakos, O.D., Barbara S. Cohn, O.D., Yaacov G. Zacks, O.D., and Michael W. Henderson, O.D.
According to the National Diabetes Information Clearinghouse (NDIC), 20.8 million Americansor 7% of the populationhave diabetes. Of that, 14.6 million have been diagnosed; but, another 6.2 million Americans remain undiagnosed.1
Diabetes is the leading cause of new cases of blindness among adults between the ages of 20 and 74. Diabetic retinopathy causes 12,000 to 24,000 new cases of blindness each year.1
Diabetic nerve disease (i.e., peripheral neuropathy) is the most common complication of diabetes, affecting up to 62% of Americans with the condition. Diabetic peripheral neuropathy is the forgotten complication of diabetes; it is often overshadowed by other complications of the disease.1
There are a number of possible reasons for the development of peripheral neuropathy, such as metabolic factors (high blood glucose or low insulin levels), neurovascular factors, autoimmune factors, mechanical injury to nerves, inherited traits and lifestyle factors.2
Since the nerves that go to the feet are among the longest in the body and are most often affected by neuropathy, patients with neuropathy need to take special care of their feet. Loss of sensation in the feet means that sores or injuries may not be noticed, and they could become ulcerated or infected. Circulation problems also increase the risk of foot ulcers. People with diabetes account for more than half of all lower-limb amputations in the U.S.86,000 amputations per year.3 Doctors estimate that nearly half of the amputations caused by diabetic peripheral neuropathy and poor circulation could have been prevented by regular foot inspection and foot care.3
Jay is a 65-year-old white male who has had type 2 diabetes for 20 years. Divorced after a long marriage, he lives by himself in an apartment. He uses a motorized wheelchair; he cannot walk or raise his legs because of advanced diabetic peripheral neuropathy. He presented for a routine examination.
Functional distance visual acuity at this visit was 20/200 O.D. and finger-counting at two feet O.S. Manifest refraction was +2.25D sphere O.D. and +1.50D sphere O.S., which provided no improvement in acuity at distance.
His recent ocular history includes proliferative diabetic retinopathy with multiple vitreous hemorrhages, clinically significant macular edema (CSME) O.U., congenital iris coloboma O.S., cataracts O.U. and nonexudative (dry) age-related macular degeneration (AMD) O.U.
His systemic history is significant for diabetes, carotid artery disease, bronchiectasis (which requires the use of an oxygen mask p.r.n.), degenerative joint disease, chronic back pain and depression. He is currently using 36 different medications for these conditions.
Jay has been a highly motivated low vision patient for several years, and he uses several devices: spectacles for distance and near, Polaroid gray filters for outdoor glare control, head-borne reading loupes (Optivisors), an expanded field bioptic spectacle telescope, closed-circuit television (CCTV), and several hand magnifiers.
At the end of his examination, Jay said, Hey, maybe someday you can help me see my feet! Because of his peripheral neuropathy, he cannot raise his feet more than six to eight inches off the ground, and he cannot bend to examine his feet due to his bad back. Since his divorce, he must have a stranger come into his home in order to do the inspections. Jay hasnt seen the bottoms of his feet in four years, even following surgical removal of one toe.
Usually, a mirror is placed on the ground for patients to inspect their feet. But, Jay is legally blind, so this method will not help him.
Jay had been fit with a focusable bioptic telescope, but this device does not facilitate inspection of the bottom of the feet. The field of view is narrow, and the depth of focus is too limited for this task. He needed a flexible device with a large magnification range, so we prescribed an electronic magnification device known as the Flipper (Enhanced Vision Systems). The Flipper is less than seven inches in height, weighs less than one pound, and features 225 camera rotation. The FlipperPort spectacles were also prescribed; with these, Jay could position the camera near his feet and view them in the spectacle lenses. Using this device and the spectacles, Jay was able to observe the part of his right foot where a portion of a toe had been surgically removed one year before. He can also use the system to inspect his scalp for lesions and to observe his syringe and injection sites.
Jays Low Vision Solution The Flipper system, by Enhanced Vision, features a camera that rotates 225 for precise positioning. The patient can view magnified images at near, intermediate or distance. It focuses automatically and displays true color on the monitor its hooked up to. It displays from 6x magnification to 50x magnification, depending on the size of the monitor to which its feeding.
The FlipperPort is a pair of electronic glassesactually, a pair of television viewing screens in miniature. It can be linked up to the Flipper for viewing anywhere. These full-color displays run on a rechargeable battery pack.
The Flipper is less than seven inches high and weighs roughly one pound. A carrying case is available, as is a one-year limited warranty. Call 1-888-811-3161, or go to www.enhancedvision.com.
Jays Low Vision Solution
The Flipper system, by Enhanced Vision, features a camera that rotates 225 for precise positioning. The patient can view magnified images at near, intermediate or distance. It focuses automatically and displays true color on the monitor its hooked up to. It displays from 6x magnification to 50x magnification, depending on the size of the monitor to which its feeding.
Jay, an engineer, even modified his Janelli clip system. He Velcro-mounted it onto the oxygen mask. Then, we inserted the trial lenses. This worked like a charm for reading while wearing his oxygen mask.
Patient history is not the only opportunity for the managing clinician to understand the patients complaint, circumstances or needs. Often, the last comment that the patient makes creates opportunities for the low vision specialist to provide unique solutions to unusual problem situations. And, as demonstrated by Jay, patients often bring creativity and skills of their own to the rehabilitation process, if the clinician provides them with the ability to experiment.
Case 2: Retinopathy of Prematurity
Retinopathy of prematurity (ROP) emerged as a cause of blindness in children in industrialized countries during the late 1940s and 1950s because of improvements in neonatal intensive care, such as supplemental oxygen and technical advances in respiratory support, which resulted in increased survival in pre-term babies.1 Today, ROP has been identified by the World Health Organization as a leading cause of visual impairment in children in the developing world.1,2
The last 12 weeks of a normal 40-week gestation period are crucial in the development of fetal eyes. In premature infants, the normal growth of blood vessels stops, and the growth of abnormal vessels is stimulated. These vessels lead to the formation of a ring of scar tissue attached to both the retina and the vitreous. As the scar contracts, it may pull on the retina, creating a retinal detachment.
Vision complications associated with ROP include: stretching of the retina/retinal detachment, strabismus, myopia, amblyopia, cataract, corneal problems and occasional visual field defects.2 Risk factors of ROP include: birth prior to 32 weeks of gestation, high levels of supplemental oxygen, birth-weight less than 1,500 grams (3.3 lbs.the lower the birth weight, the higher the incidence), concurrent illnesses, anemia, high carbon dioxide levels, seizures, bradycardia (low heart rate) and apnea.
Ed is a 55-year-old white male who has ROP. He lives alone, and he works at night in a food market. Ed also volunteers each week at a local cable television station in his community and uses public transportation. He has been legally blind since birth and relies on hand-held magnifiers, CCTV, and several types of spectacle-mounted telescopes.
His functional distance visual acuity is finger counting at one foot O.D. and 20/600 O.S. using the Feinbloom distance acuity chart. Previously prescribed low vision devices, all in the 8x to 10x magnification range, are no longer effective for reading.
Eds Low Vision Solution The LED Bar Light, by Eschenbach Optik of Roughly the size of a pencil, the Bar Light includes six LEDs along one side of the bar. This allows for the even dispersion of task lighting, the company says. The bar runs on electricity. Call 1-877-422-7300, or go to www.eschenbach.com.
The ClearImage II Telephoto Microscope, by Designs for Vision, Inc., comes in magnification powers ranging from 8x to 16x. Each microscope features a 40mm field of view.
The microscopes of stronger powers include an optional plastic shield that both protects the lens and allows the patient to keep the lens at the proper depth of focus.
Call 1-800-727-6407, or go to www.designsforvision.com.
Eds Low Vision Solution
The LED Bar Light, by Eschenbach Optik of
Roughly the size of a pencil, the Bar Light includes six LEDs along one side of the bar. This allows for the even dispersion of task lighting, the company says.
The bar runs on electricity. Call 1-877-422-7300, or go to www.eschenbach.com.
We found that a combination of devices for both magnification and light solved Eds immediate problem. First, we clipped a LED Bar Light (Eschenbach) to the bridge of a pair of spectacles. The light bar has six LEDs that can be rotated by the patient to an optimal angle, which significantly illuminates reading material. This device is essential for anyone who has ever tried using the traditional stand goose-neck lamp to place enough illumination between close-focus microscopes and reading materials.
Then, we provided the Clear Image II Telephoto Microscope (Designs for Vision), a 28mm distortion-free, multi-element microscope that is available in powers from 8x to 16x. After trying several strengths, Ed felt that the 14x (54D) lens allowed him the greatest comfort and facility when trying to read his materials from work. Because the 54D lens has such a sensitive depth of focus, Designs for Vision can place a clear plastic housing on the outside of the microscope, which enables the patient to hold the device against reading material and maintain the proper focal distance.
Case 3: NAION
Non-arteritic anterior ischemic optic neuropathy (NAION) is the most common acute optic neuropathy in the elderly population.4
NAION is characterized by a sudden painless reduction in vision, which is usually unilateral (or bilateral, if treatment of the initial episode does not occur in a timely fashion). Abnormal color vision is often another feature of NAION.
Optic disc edema is a necessary element for the diagnosis of NAION. It may be either sectoral or diffuse, but it does not typically extend far beyond the optic disc margin.4
Melanie is a 92-year-old white female patient with a presumptive diagnosis of bilateral macular degeneration and bilateral pseudophakia. She is a retired nurse and has lived in the same house for more than 50 years. She is completely alert and aware of her surroundings.
Melanie was brought to the examination by one of her sons; her other children refused to accompany her. She had to be assisted to the examination chair by her son, who then took a seat directly across the room, just beneath the acuity projection screen.
For more than one year, Melanie has experienced sudden, painless disappearance of her vision, which lasts anywhere from one to several minutes in duration. This vision loss occurs regardless of which eye is covered. Her primary-care physician recommended her to another eye doctor, who diagnosed her with AMD and explained that she has multiple scotomas, which cause things to appear and disappear in front of her. Melanie continued to complain that not just a few things disappeared, but rather, that everything did.
Her primary-care physician referred her for a carotid artery biopsy to rule out a transient ischemic attack (TIA) secondary to giant cell arteritis (GCA) or another carotid artery-related disease. All tests were negative.
At this point, her primary-care physician and vision practitioner suggested that the family seek out counseling for Melanie, and possible admission to a long-term psychiatric facility.
At this visit, Melanies distance acuity was 20/30 O.D. and 20/120 O.S. Near functional acuity was 0.33/1M O.D. and 0.33/5M O.S. Her currently worn distance prescription was -1.25D -1.75D x 175 O.D. and -2.00D -3.00D x 160 O.S.
As we raised the examination chair and then refracted the right eye, Melanie said that her vision suddenly disappeared, exactly as it had throughout the past year. We lowered the exam chair and told her to shut her eyes for a moment, then open her eyes and tell us if and when the vision returned, which was within 30 seconds. As we raised the chair again and prepared to refract her left eye, Melanie became upset and called out to her son, Where are you? I cant see anything but your legs!
Raising the examination chair had increased the angle between Melanies eyes and her son (seated across the room), making it necessary for her to look downward in order to see him. With her chin elevated, she could again see her son. When she lowered her chin, her son disappeared.
We suspected a superior altitudinal visual field defect secondary to NAION, and a visual field exam would confirm this. Therefore, the cause of her field loss was not macular degeneration-related scotomas, nor was her panic a psychiatric matter. (Subsequent visual field testing did later confirm a diagnosis of superior altitudinal visual field defects O.U.)
Melanie also informed us that she has a terrible time walking and must be assisted at all times. We asked her to walk across the room for us, and as her son assisted her, we noticed that she looked down at the floor. We educated her about compensating for the visual field defect by gazing up, but when Melanie continued walking, she informed us that she cannot see to walk when she looks up. Her glasses were very small with a flat-top bifocal segment that occupied nearly half of the vertical lens diameter. Melanie had to look down while walking in order to get the +3.00D bifocal segment out of the way. But, when she looked down, the superior altitudinal visual field defect made it impossible for her to look above the bifocal segment line. So, we prescribed a pair of single-vision spectacles for distance vision and a separate pair of single vision spectacles for reading.
We referred Melanie for orientation and mobility training to learn adaptive skills in the presence of a visual field defect and recommended family counseling for her and her family. She did not require the use of or prescription of any low vision devices.
Case 4: Multiple Sclerosis
Multiple sclerosis (MS) is a chronic disease that attacks the central nervous systemthe brain and the spinal cord. Depending on which nerves are damaged, people with MS may experience problems with balance, muscle coordination, vision, speech, thinking and other activities. The hallmark sign of MS is demyelinating plaques in the central nervous system (CNS).5
Approximately 400,000 Americans have MS. It is most common among whites (particularly those of northern European ancestry), and most people are diagnosed between the ages of 20 and 50. MS is two to three times more common in women than men, suggesting that hormones may also play a significant role in determining susceptibility. But, genetic factors likely play a more significant role in determining who develops MS.5
Elliot is a 62-year-old white male with optic atrophy and pendular nystagmus secondary to advanced MS. He needs a motorized wheelchair to get around. Elliot can use the fingers of his right hand to move his wheelchair controls. He has no use of his left hand.
Elliots Low Vision Solution The Ocutech VES-AutoFocus is a self-focusing bioptic telescope. It may be used for near or distance viewing activities. The 4x Keplerian telescope is coupled to a computerized infrared autofocusing system that measures the focusing distance more than 30 times per second at a distance as close as 12 inches.
The telescope is mounted on spectacle frames, and the patients standard prescription may be built into the lenses. If or when the patients prescription changes, the telescope may be adjusted or remounted, if necessary.
The separate battery pack operates the telescope for up to eight continuous hours before it must be recharged. Call 1-800-326-6460, or go to www.ocutech.com.
Elliots Low Vision Solution
The Ocutech VES-AutoFocus is a self-focusing bioptic telescope. It may be used for near or distance viewing activities. The 4x Keplerian telescope is coupled to a computerized infrared autofocusing system that measures the focusing distance more than 30 times per second at a distance as close as 12 inches.
We presented the AutoFocus Bioptic Telescope (Ocutech VES) to Elliot. It is a self-focusing bioptic spectacle telescope that provides 4x magnification and has an infrared auto-focusing system. It provides a magnified image as close as 12 inches, as well as a reasonable field of view. The telescope comes with a rechargeable battery, which we attached to Elliots clothing to prevent the control from falling beyond his reach.
With this device, Elliots functional acuity becomes 20/40. His wife mounts the system on his wheelchair and adjusts the position of the telescope to achieve optimal comfort. Elliot controls the system with his right hand, and he has experienced improved recognition of faces and watches television for one hour at a time with the system. (The company generally recommends a visual acuity of no less than 20/150 for this 4x system. Merely by adjusting the users distance from the desired focal point, however, additional relative distance magnification can be achieved with this system.) Before Elliots positive experience with this device, he simply spent many hours each day asleep. Now, he can experience some enjoyment watching TV.
Low vision practitioners have to think a bit outside of the box in order to find beneficial treatments for individuals with partial sight. We hope that these cases will draw more practitioners to this meaningful specialty in vision care.
Dr. Frank is an associate professor at the New England College of Optometry and the chief of the Low Vision Service of the New England College of Optometry"s Clinical Division, the New England Eye Institute. Each of the other authors was a student intern under Dr. Frank at the the New England Eye Institute. All participated in the examination of the patients discussed in this article.
1. Wild S, Roglic G, Green A, et al. Global prevalence of diabetes: Estimates for the year 2000 and projections for 2030. Diabetes Care 2004 May;27(5):1047-53.
2. Good WV, Carden SM. Retinopathy of prematurity. Br J Ophthalmol 2006 Mar;90(3):254-5.
3. National diabetes information clearing house. (NDIC). NIH publication #073185. May 2002.
4. Buono LM, Foroozan R, Sergott R, Savino P. Nonarteritic anterior ischemic optic neuropathy. Curr Opin Ophthalmol 2002 Dec;13(6):357-61.
5. The National Multiple Sclerosis Society. National Multiple Sclerosis Sourcebook. 2006. Available at: www.nationalmssociety.org/site/PageServer?pagename=HOM_LIB_sourcebook (Accessed August 2007).