L. Windsor, O.D., F.A.A.O.
Laura K. Windsor, O.D.
Published in the Rehabilitation Professional Journal , Spring 2001
On October 19, 1999 the National Eye Institute recognizing the growing number of visually impaired individuals in the United States and the under utilization of low vision rehabilitation, launched their National Low Vision Education Program. Carl Kupfer, NEI Director, said at its inception:
ďThe impact of low vision on a personís quality of life can be devastating... But people should not accept the statement that nothing could be done about their low vision. People with low vision can improve their quality of life through vision rehabilitation services to teach them how to use their remaining vision more effectively. Using a variety of visual and adaptive aids may bring them back or help them keep their independence.Ē[i]
Low vision is defined as a visual impairment not corrected by standard eyeglasses, contact lenses, medicine or surgery, which interferes with the ability to perform everyday activities. Visual impairment may present as reduced visual acuity, visual field loss, loss of contrast sensitivity, photophobia, diplopia, metamorphopsia (wavy distorted vision), visual perceptual disorders or as a combination of these. In simple terms, low vision may be thought of as the best-corrected vision, which is insufficient to do what the patient needs to do.[ii]
There are 135 million visually impaired people worldwide. Fourteen million or 1 in every 20 Americans are visually impaired, but only about 120,000 of them are totally blind or have only light perception.[iii] Thus, the majority of visual impaired patients have significant residual vision and most may benefit from low vision rehabilitation. The cost to society including educational, loss of income, services and disability exceeds 22 billion dollars in the United States each year.[iv] With one third of the American population approaching 65 and people living a much longer life, the total number of visually impaired is expected to increase dramatically in the next 50 years.
The most common cause of vision loss is age related macular degeneration, which accounts for half of all cases of visual impairment. Other common causes of low vision include diabetic retinopathy, retinitis pigmentosa, Stargardtís, albinism, glaucoma, retinal dystrophies, retinal detachment, uveitis, retinopathy of prematurity, histoplasmosis, achromatopsia, optic atrophy, toxoplasmosis, stroke, brain tumors, traumatic brain injury, corneal degeneration and eye injuries.
impacts all aspects of life including occupational, educational and
recreational. Children with low vision may suffer developmental and educational
delays. Adults with low vision commonly face losing their jobs due to their
impairment. Senior citizens, who
are the largest segment of the visually impaired, are subjected simultaneously
to other health and social problems associated with aging, all of which impact
OF LOW VISION REHABILITATION
Massof from the Wilmer Eye
Institute defines success in low vision rehabilitation as a reduction in the
level of difficulty in performing a particular task or goal, or the reduction in
the importance of that task by teaching the patient alternative strategies to
achieve the goal.[v] Scott et al at the Bascom
Palmer Eye Institute used the National Eye Instituteís Visual Functioning
Questionnaire to study the success of low vision care. Over 98% showed
subjective improvements with care and 53.2% reported low vision services as
ďvery usefulĒ. This study concluded that low vision services are associated
with high patient satisfaction. [vi]
A study by Nilsson followed
79 patients with advanced diabetic retinopathy over a 3 to 6 year period. After
receiving low vision care, the number of patients able to read newspaper text
increased from 1.3% to 97.5%, and 72% of the patients who were forced to stop
working due to their vision loss had returned to work.
Demers-Turco from the Department of Ophthalmology at Harvard Medical School
concluded that the ď unique and complex needs of people with diabetes who
experience vision loss can be well addressed through timely and ongoing vision
rehabilitation servicesÖĒ [viii]
A telephone survey conducted
by Watson et al reviewed 200 veterans using 740 low vision aids at 12 and 24
month intervals after low vision services were first obtained and found that
85.4% of devices were still in use. [ix]
Van Rens et al retrospectively reviewed 261 cases to find that low vision aids
were used successfully used by 77% of those receiving low vision devices in
patients ranging from 16 to 95 years old with a mean age of
Collee et al studied 71
patients with Stargardtís disease, a form of juvenile macular degeneration.
Reading and distance vision after low vision services was improved in all cases.[xi]
Schwartzenberg et al found 80% of a group of 15 Stargardtís patients used
their low vision aids successfully.[xii]
Leat et al at the University
of Waterloo School of Optometry studied the perceived benefit in 57 elderly
patients receiving low vision services. They found 89.5% reported benefits and
81% regularly used their low vision aids. Perceived benefits were associated
highly with the ability to perform daily activities.[xiii]
Temelís study of 185 patients found that 77% of his test group benefited from
low vision aids.[xiv]
Sellier et al found that in a study of 51 patients with macular degeneration, 76% of the patients with the wet form and 65% of those with the dry form used low vision aids every day.[xv] Ji et al reviewed 118 cases at a medical school low vision clinic and 70% expressed improved vision with the use of low vision aids.[xvi] The impact of low vision services for severely brain-injured patients was studied by Gianutsos et al. In a population of 51 patients, 26 received low vision care, and all of those patients benefited from this care with and most judging low vision services as having a significant beneficial impact on their lives.[xvii]
The rehabilitation of a visually impaired individual may involve a variety of treatment modalities including prescription eyewear, optical devices, electronic aids, adaptive computer software, glare control, modification of the patientís environment, counseling and education of the patient and family, skills training, independent living aids, occupational therapy, mental health intervention, orientation and mobility training and driving rehabilitation. A cadre of rehabilitation professionals skilled in these specific areas has emerged.
Low vision rehabilitation begins with a careful evaluation by an optometrist or ophthalmologist skilled in low vision rehabilitation. An understanding of the underlying disease or injury is crucial. Each disease or injury has unique functional characteristics. For example, rod/cone dystrophies, such as retinitis pigmentosa, may result in loss of peripheral vision, night blindness, loss of contrast sensitivity and ďwhite-out glareĒ in bright light.
In contrast, patients with central retinal disorders like Age Related Macular Degeneration, histoplasmosis maculopathy and Stargardtís may present with a loss of central vision and photophobia, but retain their peripheral vision. The patientís mobility may be adequate while being unable to read or recognize faces. The low vision examination by an optometrist or ophthalmologist skilled in low vision rehabilitation defines these physical and functional limitations.
The low vision examination is quite different from the basic eye health and refractive examination routinely performed by primary care optometrists and ophthalmologists. The goals of the low vision exam include assessing the functional needs, capabilities and limitations of the patientís visual system, assessing ocular and systemic diseases and their impact on functional vision, evaluating and prescribing low vision systems and therapies. Also, educating and counseling the patient, family and other care providers, providing an understanding of the visual functioning to aid educators, vocational counselors, employers and care givers, directing further evaluations and treatments by other vision rehabilitation professionals and making appropriate referrals for medical and surgical intervention is all a necessary part of the low vision evaluation.
The low vision examination begins with an extended case history including a chief complaint, any current problems, and treatments of their condition. Additionally, it includes a careful medical and social history. The emphasis of this history is to understand how the patient is functioning and what needs the patient has.
Low Vision Related Health Requirements: Does the patient have health problems or treatment requirements that will impact low vision recovery? If the patient is a diabetic, can the patient see to fill insulin syringes, read nutritional labels on food containers and see to monitor their foot care? Is the patient taking medications that may impact their vision and can the patient see to identify their medications?
Reading and Near Vision: What are the reading requirements and desires? Does the patient need or wish to read specific materials, a church newsletter, the newspaper or their mail? What happens when the patient attempts to read? What can the patient read (newspaper print, large print, or large headlines)? Is eyestrain or ocular fatigue present? Is the patient an avid reader? Has the patient used talking books? What low vision devices have been tried?
Intermediate Activities: Can the patient see to perform other near point and intermediate visual activities like writing, sewing, cooking, and viewing the computer? Can the patient see to write checks and balance their checkbook? Do they use large print (deluxe guide) checks? Can they see to use a calculator or a watch?
Activities of Daily Living: Are the patientís appliances marked to improve visibility? Has services of a rehabilitation teacher or occupational therapist to improve homemaking skills been consulted? Can the patient see to do other routine housekeeping duties like cleaning, paying bills, and laundry?
Computers: Are computers used? How large is the monitor? What type of work is being done? How close must the patient sit to the computer screen? Is computer enlargement or voice software used? Does the patient wear dedicated eyewear for the computer? Is the patient able to access the Internet?
Recreation: What is done for recreation? Does the patient have a hobby? Can the patient view the television? How close do they sit? How large is the television? How well do they see the colors on the screen?
Mobility: Are there any mobility issues? Can the patient travel independently? Does the patient use a long cane or guide dog? Does the patient run into objects or trip on curbs? Has the patient had mobility and orientation training? Does the patient take trips? How do they travel? Are their any difficulties? Does the patient have a handicapped-driving placard?
Driving: Does the patient still drive, and if so, when and with or without a valid license? Have there been accidents or traffic violations? When will the license expire? Does the family support continued driving? Has patient limited their driving? Is someone else available to drive? Is public transportation available?
Light & Glare: How does the patient function in bright sunlight, inside lighting and at night? Are sunglasses worn? What color and type? Does the patient use a hat or visor? Does light and glare affect the patientís mobility? Does the patient have difficulty changing from different light levels? Is there a residual decrease in vision after coming inside from bright light? How does the patient function at night?
Vocational: Is the patient employed or doing volunteer work? What type of work was done in the past and did the patient leave their job because of their vision problems? Is the patient now seeking employment? What are the visual requirements for their job? Has the lighting, visual environment of the job and position of equipment been adapted to fit the patient? Are their safety issues? Is appropriate eye protection worn?
Educational: Are there specific educational needs? Are educational programs adapted to the patientís visual abilities? What educational services are available? Does the student work with a visual impairment teacher? Does the student use large print textbooks? Can the student see the chalkboard? Are there computer requirements? Is the child attending a blind school or in a mainstream program? If a college student, what is the major area of study? Will the patient be able to handle the increased reading required in college? Will there be mobility or transportation issues in attending school? Is there access to computer technology adapted for visual impairment, closed circuit magnification, audio textbooks or a personal reader/note taker?
Emotional: How motivated is the patient? What support is available to the patient? Does the patient have family or friends to provide support, help with housework or transportation? How is the patient adapting emotionally? Have there been signs of clinical depression? Has the patient reported visual hallucinations? Visual hallucinations in the visually impaired have been reported for over two hundred years since first described by Charles Bonnet, a Swiss naturalist, who observed these hallucinations in his grandfather.[xviii]
Following the detailed history, vision functions are assessed. The tests and techniques are adapted to fit the patientís visual impairment. And are adapted to help assess the patientís vision.
A more accurate measure of the patientís refractive status and visual acuity can be obtained with low vision refractive techniques. These tests employ larger testing charts, control of illumination, the use of trial frame refraction, and techniques that allow for eccentric viewing. In 1992 as outlined by Windsor, many of these special testing techniques were outlined.[xix] Best visual acuity in an examination room, however, may not be duplicated in the patientís home where lighting and contrast may be poor. [xx] In infants and non-verbal patients, special testing techniques can be employed. The use of Teller acuity cards may be a good test for moderately impaired infants and children. Additionally, a functional battery, which involves observing the patient in a variety of activities, may provide strong evidence of the childís visual function.[xxi]
Additional understanding of the patientís functional vision can be obtained through the use of the Amsler grid, contrast sensitivity, the laser-scanning ophthalmoscope, visual evoked potential and electroretinogram. Contrast sensitivity tests the eyeís ability to discriminate subtle changes in vision rather than the absolute black-on-white contrast of a visual acuity chart. Contrast sensitivity is a better predictor of real world functioning.[xxii] The use of a laser-scanning ophthalmoscope allows one to plot the precise area used by the patient with central retinal damage.[xxiii] The visual evoked potential or VEP, a form of electroencephalogram, shows an increasing role in the assessment of patients with a brain injury.[xxiv] Electroretinograms are helpful in the differential diagnosis of many retinal diseases. [xxv]
Ocular motility testing should be carefully evaluated. Rundstrom demonstrated the importance of binocular vision testing in low vision patients. [xxvi] Also, Schlageter found 30 out of 51 patients had impaired eye movements and reduced ocular convergences after suffering a traumatic brain injury.[xxvii] Additionally, patients with severe tunnel vision may experience a breakdown in binocular vision. Pituitary tumor patients with bitemporal hemianopsias may experience hemifield slide, a unique form of double vision where rather than seeing two objects, the patients sees two halves of the object.
While visual field testing is used to diagnose ocular and neurological diseases, it can also predict how the low vision patient may function in day-to-day activities and how well the patient may respond to various rehabilitative approaches.[xxviii] Visual fields may be tested by confrontations, manual perimeters or by computerized perimetry.
The Behavioral Inattention Test
is a helpful screening test for unilateral neglect.[xxix]
In the right brain injury patient, unilateral neglect or hemifield neglect may
mimic hemianoptic field loss. Visual neglect, however, is a spatial inattention.
It can occur independently or as an accompaniment with homonymous hemianopsia.
Another very important part of the low vision exam is the dilated internal examination, intraocular pressures and external eye health evaluation. These ensure that there are no ocular diseases or complications that may require treatment or referral to another specialist.
Magnification is a major tool of low vision rehabilitation. But how do we obtain that magnification? Moving closer to an object provides magnification. The aged related macular degeneration patient might move closer to the television. The low vision child may hold reading material only a few inches away. Magnifiers, strong bifocals, telescopic systems, microscopic systems, closed circuit television systems, large print, and computer screen magnification programs may all provide effective magnification for low vision patients.
Magnifiers are one of first low vision devices selected by patients, but unfortunately without professional guidance, patients frequently obtain magnifiers that are too low in power, too heavy and often without needed internal illumination. Small pocket magnifiers might be used to read a price tag or a menu, while larger illuminated stand magnifiers may be used at home or work. Magnifiers with brighter halogen and xenon illumination often improve reading, particularly in age related macular degeneration patients.
Strong bifocals, dedicated reading glasses and microscopic eyewear may improve reading. Patient acceptance, however, may depend on their willingness to hold reading materials close. The Designs for Vision Type R‚ microscopic bifocal provides outstanding optics, but may require a working distance of only a few inches. Near telescopes, like those worn by surgeons and dentists, are used to read at greater distances and are mounted within or attach to eyewear.
To magnify distance objects, telescopic systems are frequently used. These may be handheld or mounted in eyewear called bioptics. Thousands of mildly visually impaired patients in the United States use bioptics to drive, watch television or do other distance tasks. Beecher Researchís telescopic system, the Beecher Mirage‚, is a lightweight binocular system that is worn like eyewear for distance viewing. We have found it to be an exceptional aid to view television even in patients with visual acuities below 20/600.
Telescopes may be attached to prescription eyewear to create what is called a bioptic system. Bioptic eyewear design has evolved from large telescopic tubes to smaller, more cosmetic telescopes. Modern bioptic design includes many, small lightweight systems that have improved patient acceptance such as the Vision Enhancement System‚ introduced by Ocutech ten years ago.[xxx]
Recently, Ocutech has introduced an auto focus version, the VES-Autofocus‚. It is a monocular 4X bioptic telescope mounted above the eyeglass frame. Powered by a rechargeable battery, it contains two computer chips and an infrared focusing system similar to that found in an auto focus camera. VES-Autofocus can focus automatically from 12 inches to infinity in a fraction of a second, and has dramatically changed the purposes for which we prescribe bioptics. Rather than being used for one or two specific tasks, these systems are being worn fulltime and more importantly, the patients using this system regain a sense of personal space and an ability to better interact with people. They can again see facial expressions and notice body language, subtle yet important aspects of everyday communication.[xxxi]
Magnification from telescopes, magnifiers and microscopic lenses is limited by their design, and can rarely be used successfully above magnification of 20X. Closed circuit television systems are capable of higher levels of magnification and can manipulate the brightness and contrast of the image. Video magnification has been reported in the literature for over four decades. [xxxii] [xxxiii]
The concept of a CCTV is simple. A video camera is used in real time to capture the image of the reading material and display it on a monitor. For example, the poor contrast of newspaper print can be enlarged 40X, but can simultaneously be converted to white letters on a black background. The CCTV evaluation should include testing with real world items including newspapers, telephone books, utility bills, an addressed envelope, a handwritten letter, a greeting card, magazines, a checkbook, photos, a can of food, a medicine bottle, the patientís fingernails, a tax form, an address book, a recipe, and jewelry. Filling an insulin syringe or performing glucometry should be demonstrated for the insulin dependent diabetic. Preferences for image size, type of contrast, color and the ability to operate the system should be determined. Motion problems from moving the image on the screen may be reduced with larger monitors that allow displaying more text at one time.
New innovations in CCTV technology are expanding their use and availability. The Jordy‚ system, introduced by Enhanced Vision Systems is a wearable full color CCTV system that includes a camera and two LCD screens mounted in a headset. It can operate on a battery or direct current. This system provides up to 27X magnification through the headset providing dramatic improvements in distance vision for many profoundly impaired patients. It can also be placed in a stand with a X-Y table and connected to a television monitor for functioning like a traditional CCTV. The Jordy‚ has the potential to aid profoundly impaired patients. When worn on the head, the 27X maximum magnification far exceeds that of the typical bioptic or monocular telescope. The Jordy‚ may also be attached to a larger television monitor such as a 32-inch portable to provide much higher levels of magnification than most console CCTVs.
Other innovations include the Flipperport‚ by Enhanced Vision Systems and the ZACC Plus‚ by OVAC, which include tilting cameras that allow viewing across the room. The Personal Vision Assistant‚ (PVA) employs a detachable mirror, which magnifies the face for shaving or applying makeup. Also, the cost barrier for CCTV technology has been broken through the introduction of small inexpensive handheld CCTVs that attach to any television.
Visual field loss impacts the ability to safely navigate in the real world. The hemianoptic patient and tunnel vision patient may run into objects or trip and fall.[xxxiv] Visual field loss requiring treatment include general constriction or tunnel vision as seen in retinitis pigmentosa or sectorial losses such as a homonymous hemianopsia, a loss of one half of the visual field in each eye caused by damage to the opposite side of the brain. Scanning therapy, visual field awareness prisms, reverse telescopes, orientation and mobility training, occupational therapy and guide dogs may all be employed in the rehabilitation of patients with field loss.
Reverse telescopes aid tunnel vision by minifying the image so a wider area of information falls within the patientís residual field of view.[xxxv] Visual field awareness prisms work by displacing the image from the periphery towards the residual vision. So with only a slight shift of the head, the patient becomes aware of objects to the impaired side and can then turn their eyes to view the object.[xxxvi] [xxxvii] [xxxviii] [xxxix] [xl] [xli] The Visual Field Awareness System‚ (VFAS) developed by Rekindle is a sectorial prism system mounted on the side of the vision loss. It provides improved optics over traditional press-on prisms.[xlii] In hemianoptic patients, sectorial prisms have been shown to improve patient functioning in activities of daily living.[xliii]
& GLARE CONTROL
Filters that reduce the
transmission of shorter wavelengths of light frequently benefit low vision
patients. Zigman has demonstrated photographically that these yellow and amber
filters reduce chromatic aberration, light scattering and fluorescence.[xliv]
Evaluation should include considerations of both inside and outside glare
problems. Hats and visors may be used to reduce ambient glare as well. Both the
patient and family should be counseled in control of glare and use of adequate
Soft contact lenses with
central red or amber filters reduce the severe photophobia of patients with
achromatopsia and cone /rod dystrophies. In aniridia, a congenital lack of the
iris, soft contact lenses can be painted to create artificial irises and help
reduce the extreme photophobia these patients experience. The blurred vision
caused by keratoconus and anterior membrane corneal disease may be aided with
gas permeable contact lenses by creating a smooth refractive surface.[xlv]
Contact lenses maybe used to improve vision in nystagmus patients also.[xlvi]
AND LOW VISION
usage creates a new set of problems for visually impaired patients. Adaptive
steps include larger monitors, screen enlargement software, large letters for
the keyboard, voice systems, near telescopic systems, and dedicated computer
eyewear. Computers may also be employed to scan and read text. The patientís
ability to access the Internet is often an important task. New low vision
products are emerging that offer new opportunities for the visually impaired by
utilizing electronic and computer technologies. These must become an integral
part of the comprehensive low vision evaluation.
During the examination, the patient should be introduced to independent living aids and to the concepts of adapting their home and workplace. Older patients often have both visual and physical limitations to be addressed. Lighting, contrast and safety issues may need to be assessed in the patientís own home. The most effective approach is a home evaluation by an occupational therapist or rehabilitation teacher.
Hi-Marks‚, a low vision marking material and Loc Dots‚, small paste on raised tactile dots are helpful in marking appliance dials. Additionally, large print versions of books, checks, playing cards, calendars, and writing paper are available. Also, the simple change from a ballpoint pen to a bold fiber tipped pen can improve the legibility of writing. The use of these aids and services may greatly benefit the patient.
The dispensing of low vision aids requires careful training of the patient in the correct usage of the aid. Langmann et al found that the failure rate of patients using low vision systems decreased from 22% to 3% with improved training.[xlviii] Even a simple magnifier can be difficult to use if it is held at the wrong working distance. Donít rely on memory of the trainer or the patient! Check-off lists may address each issue that must be taught to the patient for each low vision aid. Large print instruction sheets should be available for the patient to take home with them.
The history, physical
examination, functional assessments of vision, and evaluation of low vision aids
come together with the patientís goals and diagnoses to allow for the
development of a rehabilitation plan. It becomes the initial blueprint for low
vision rehabilitation and should consider each of the following areas:
Eyewear: Should the patientís
general eyewear be changed? What
types of prescription eyewear are advised? What type of material and lens style?
Are filters, antireflection coatings, ultraviolet coatings advised? When
should it be worn? Are there eye safety issues?
Light and Glare Control: Is a sunglass required? What color? Is supplemental task lighting required? Has a hat or visor been advised? Should the work, home or office lighting be modified?
Optical Aids for Use at Near and Intermediate: Are magnifiers or dedicated microscopic reading eyewear required for reading or other close or intermediate tasks?
Optical Aids for Use at Distance: Is a bioptic system, hand held telescope or head worn binocular aid required?
CCTV System: Does CCTV technology aid the patient? Which systems are recommended? Where will the system be used and for what purposes? What features are required? Which type of contrast is best for the patient? How large a monitor is required? Is color required? Are there physical limitations that may require further training?
Visual Field Rehabilitation: Are visual field awareness prisms or reverse telescopes indicated? Is scanning therapy being prescribed? Are adaptive strategies being prescribed?
Computer Vision Considerations: Is a computer required for vocational or occupational needs? What size monitor? Is screen enlargement software advised? Is screen reader required? Is dedicated computer eyewear or bioptics required? Are technical computer adaptations required that may indicate the need to refer the patient to a technology specialist?
Electronic Reader Machines: Is a dedicated electronic reading system indicated? Can software and/or scanner be added to the patientís existing computer?
Patient and Family Education / Counseling: Have the patient and family been counseled on the condition, visual effects, the rehabilitation process, and safety issues? What literature or videotapes, are being provided? Has the patient been directed to specific web sites or to the practice web site for additional information? The low vision practice web site allows the doctor to provide updated information on the latest products, online manuals for products they may be using and can direct them to websites specific for their condition.
Medical Surgical Issues: Are other medication treatments indicated? Is referral indicated to other specialists? Have orders or prescriptions been written?
Binocular Vision and Eye Motility Issues: Is prism, occlusion or orthoptic therapy required in office or at home?
Low Vision Training: Is home and/or in office training for eccentric fixation or scanning being prescribed?
Rehabilitation Teacher: Is a referral indicated for training in independent living aids or Braille? Does the patient require home modifications?
Motility and Orientation Training: Is orientation and mobility training indicated or has the patient already been trained? Is a guide dog a consideration?
Driving Issues: May the patient continue to drive? What warnings were given? Is referral for a driverís rehabilitation evaluation advised? Are we requesting a Bureau of Motor Vehicle behind-the-wheel driving evaluation? Is the patient a candidate for bioptic or hemianoptic driving rehabilitation?
Vocational Counseling: Is referral to a vocational rehabilitation counselor advised? Is the patient referred for disability certification?
School VI Teacher / Special Education Programs: What recommendations are to be made to teachers, the visual impairment teacher or the special education department? Is there a preferred seating position? Is special classroom adaptation required? What devices such as CCTVs are being requested for the school to provide? What treatments should be added to the patientís educational plan?
Psychological, Psychiatric or Neuropsychological: Is a referral for general psychological or psychiatric consultation advised? Has the patient refused referral? In the brain injury patient, is a neuro-psychological consultation indicated?
Support Groups / Patient Information: Has the patient been referred to a support group or to a patient ambassador program? What patient information, forms, brochures and videotapes have been dispensed?
Reports: Who should receive reports (referring professional, eye care providers, physicians, therapists, teachers, family, patient, vocational rehabilitation counselors, teachers and case managers)?
Third Party and Funding Issues: What steps do we need to perform to aid the patient in finding funding or in providing information to their insurance company, reports, cost statements, and/or statements of medical necessity?
Follow-up Care: When should the patient return for progress evaluations? Is a full re-examination date advised? Has the patient been released back to his primary care provider?
Mary was first examined in 1989 at age 33. She presented with a history of aniridia and aphakia with a history of cataract surgery for congenital cataracts. Aniridia is a congenital disorder in which the iris fails to form leaving the patient with the functional effect of being permanently dilated. It is associated with extreme photophobia, cataracts, glaucoma, impaired vision and other systemic disorders. Her goals were to control her extreme photophobia, become a licensed driver and improve her reading vision. She worked as a speech therapist at several area hospitals and needed to drive to work.
For many years, Mary had worn conventional soft contact lenses for aphakia. Her visual acuities with contact lenses were 20/200 in both eyes. She was evaluated and fit with pseudo-iris aphakic soft contact lenses that have a painted opaque artificial iris with a 3 mm clear central pupil. Her visual acuities immediately improved to right 20/100 in both eyes and her photophobia was dramatically reduced. High plus reading glasses were prescribed to improve her reading.
In 1991, she was prescribed a 3X Wide Angle‚ Designs for Vision bioptic eyewear. This telescopic system improved her distance visual acuity to 20/40 in both eyes. Sun filters were adapted to fit behind her bioptic eyewear to control residual glare. Her bioptic visual acuities, visual fields and color vision met the requirements for the Indiana Bioptic Program.
Mary was trained in the use of the bioptic over a period of three months. When she demonstrated effective skill in using the bioptic eyewear, she was referred to a driving rehabilitation specialist for a driving evaluation and training. This included reaction time testing, perceptual tests and a behind-the-wheel driving evaluation. Upon our documentation of her potential to become a bioptic driver, and that of the driving specialist, the Indiana Bureau of Motor Vehicles issued her a bioptic training permit. She completed 30 hours of driving rehabilitation and passed an extended behind-the-wheel evaluation with the Indiana Bureau of Motor Vehicles. She was licensed in 1991 and nine years later, Mary continues to drive with her bioptic eyewear. Maryís ability to drive, read and control her photophobia has allowed her to continue her work full-time as a speech therapist.
Stacey was a 37 year-old female when she suffered a cerebral vascular accident due to a right carotid artery dissection in August of 1996. She was referred to us by her occupational therapist and reported difficulty in mobility, which included falling frequently and running into objects on her left side. She reported being afraid to walk across the floor in her home for fear of stepping on her small children. Another doctor had advised her nothing could be done.
Visual acuities were right 20/50 and left 20/30. Smooth pursuit eye movements showed saccadic replacement on movements to the right side. Optokinetic nystagmus was poorly defined on movement of the drum to the right side. Visual field testing by automated perimetry demonstrated a dense left homonymous hemianopsia. She was alert and attentive with no aphasias, but had a left hemiplegia. She demonstrated problems with spatial disorganization and a possible mild left hemi-neglect. The findings suggested a right parietal lobe lesion rather than a pure occipital lobe lesion.
Stacey was evaluated with a Visual Field Awareness System‚ developed by Gottlieb. She immediately responded with more awareness of objects on her left side. The system was prescribed with a new prescription that included a bifocal correction that improved her reading. This system unlike previous press-on versions is mounted only on one lens on the side of the visual field loss and provides a clearer image than press-on prisms. The VFAS works by shifting the image towards the residual visual field so that with a slight shift of fixation by the patient, objects to the side of the system are noticed. Home scanning therapy was prescribed.
Stacey underwent extensive occupational and physical therapy. Stacey was also taught adaptive strategies such as using boundary marking along the left edge of printed material to avoid confusion on where to start the next line. Due to her spatial perceptual problems, Stacey was not a candidate for driving rehabilitation.
Stacey continues to use the VFAS‚ full-time. She reports that it has changed her life. She can travel with safely and rarely runs into to things. She has returned to do volunteer work at her childrenís school.
Richard was a 67 year-old male when first examined. He had a history of exudative macular degeneration, which had been treated with laser photocoagulation and drusens of his optic nerves. He presented with visual acuities of right 20/160 and left 20/200. Richard had been previously examined by another low vision specialist and had an Aladdin‚ CCTV system and the original manual focus Visual Enhancement System‚ bioptic telescope.
Richardís primary concern was his ability to do day-to-day activities like seeing faces, writing checks, shopping and watching television. He was married and thus could rely on his wife for driving and cooking. His Aladdin‚ still provided adequate reading vision at home, but he needed something to help him ďjust see better.Ē
He was switched from the manual 4X VES‚ to the newer 4X Auto Focus VES‚. Richard has worn his system fulltime for two years. It allows him to meet his goals of writing checks, seeing faces and other general activities of daily living. He found that it provides that ability to ďjust see better.Ē He can now interact we people at reasonable distance. He no longer has to invade the personal space of other to see them.
Jennifer was first examined in 1988 at age 7. Jennifer, her sister and father all had a history of oculocutaneous albinism. Oculocutaneous albinism is an inherited metabolic disorder involving the eyes, hair and skin. It is associated with an underdeveloped macula, photophobia, nystagmus and a significant refractive error.
Jennifer demonstrated severe photophobia and nystagmus. She wore single vision eyewear for hyperopia and astigmatism. She presented with visual acuities of 20/160 in both eyes. Refractive testing showed that Jennifer was under corrected in her present eyewear. Increasing her prescription improved distance vision to 20/120 in each eye. Additionally a + 3.00 bifocal improved Jenniferís near vision. Low vision children read at very close distances, often at 4 to 6 inches. Though children have more focusing ability than adults, they often fatigue in maintaining this near point focus through an entire school day. Providing a bifocal at school age can improve the childís comfort. To control the photophobia from her albinism, a filter was placed in her eyewear and sunglasses were provided. Sunscreen protection and hats were advised in all daytime outside activities. Over the last twelve years, the bifocal power has been gradually increased to compensate for the natural reduction in her accommodation or focusing ability, the increase in required reading and the smaller size print at higher-grade levels. Today, Jennifer wears a +6.00 bifocal.
Throughout her school years, we have provided input to her school and recommendations for her Individual Education Plan. Jennifer is about to begin college and has been fit with a 4X manual Ocutech Visual Enhancement System‚, which allowed her to obtain 20/30 vision with her right eye. It allowed her to proceed towards becoming a bioptic driver. She will complete training in the use of the bioptic with our staff and then be referred for a driving rehabilitation evaluation and thirty hours of behind-the-wheel training.
Troy is a 27 year-old male with a history of profound vision loss from a traumatic brain injury with bilateral optic atrophy. A tree limb struck Troy in the head at age 2. He was unable to read, see to travel unassisted and was unable to recognize faces. He reported an interest in computers, but had difficulty seeing the screen. He had used a CCTV in the past, but no longer found it helpful. He wears prescription eyewear fulltime for protection.
He presented with visual acuity of right eye 20/1400 and left eye hand motion. Visual fields were profoundly constricted. Troy did not find optical magnification (telescopes, microscopes and magnifiers) helpful.
Troy was fit with the Jordy‚ system. The Jordy‚ is a closed circuit television magnification system (camera and LCD screens) that may be worn on the head allowing viewing up to 27X magnification through the LCD screens in the headpiece, and can be placed in a stand and connected to a television monitor to function like a traditional CCTV system.
The advantage to Troy was that at 27X magnification while worn on his head, it could provide more magnification than any bioptic system available. Additionally, by connecting to a 32-inch television, over 100X magnification is possible. Troyís visual acuity with the Jordy‚ increased from 20/1400 to 20/40. He saw his fatherís face clearly for the first time that he could remember.
To aid Troy at the computer, screen enlargement software with speech was advised. Troy was switched from glass photochromatic lenses to polycarbonate photochromatic lenses. Both darken and lighten in sunlight, but the polycarbonate provides much greater protection from breakage. Patients with only one functional eye should not be placed in glass lenses. Safety of the remaining eye must always be a consideration in eyewear prescribed for low vision patients.
Today, Troy uses his Jordy‚ to operate his computer and other electronic devices, to see to interact with people, to work with his hands and to read. Troy is an example of a profoundly impaired patient who benefited from new technology to regain a more functional level of vision.
Francis was a 56 year-old
insulin dependent diabetic with a history of vision loss from bilateral diabetic
macular edema when he was first examined. He had previously undergone bilateral
focal macular laser photocoagulation and bilateral cataract extraction with
intraocular lens implants. He presented with visual acuities of right eye 20/200
and left eye 20/160. Contrast
sensitivity was profoundly impaired at all frequencies. Diabetic protocols were
reviewed. These include his ability to fill his insulin syringe, to perform
glucometry measurements, to read nutritional labels on food products, to see
other medications and to check is own feet for peripheral neuropathies. Francis
reported inability to read normal print, to see to fill his insulin syringe, to
see his feet, to watch television and discomfort in bright light. His wife
performed all cooking and could fill his syringes when present.
Low vision refraction improved his vision to right eye 20/120. Prescription trifocal eyewear was prescribed with a light amber gradient filter. A darker polarized amber sun filter was dispensed for wear in the sun. A 5.5 X Beecher Mirage‚ improved his distance vision to 20/30 and dramatically improved his ability to watch television. A MAX‚ handheld CCTV and +12.00 BI-prism half eye reading eyeglasses were prescribed for reading. The MAX was connected to his own 19-inch television. A 5X lighted magnifier was also prescribed. Artificial tears were prescribed for a mild dry eye problem. Francis was not a candidate for bioptic driving. Because of his vision, he was advised to have his wife and doctor monitor his feet.
Thirty months later, Francis was re-examined. He reported the use of the amber filter in his general wear eyeglasses and in his sunglasses had greatly improved his comfort. Diabetics, particularly those after laser photocoagulation experience significant glare problems that respond well to amber filters. He reported using his Beecher‚ to watch television daily and using his MAX‚ at home to read. His reading eyewear continues to allow him to fill his insulin syringes.
As the number of visually
impaired individuals is growing, there is a greater need to provide
comprehensive low vision services to these patients. As demonstrated throughout
this article, low vision services help patients with vision loss keep their
independence and jobs, continue their education and allow them to continue to do
activities of daily living. However, low vision rehabilitation is not a single
aid or device, but rather a continuum of services and products provided by a
cadre of rehabilitation professionals.
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