Aging Vision - Harvard University

Aging&Vision

A publication for Practitioners, Researchers and Educators

Volume 15 Number 1 Spring 2003

Orientation and Mobility: Crucial to
Adapting to Life with Vision Loss

by Cynthia Stuen, DSW

Aging and vision professionals serve Orientation and mobility In This Issue
an ever-growing older population professionals strive to maintain,
who turn to the Lighthouse for and increase, quality of life for ● Low Vision Mobility
strategies to cope with normal age- the older population through Research in the
related vision changes, as well as work as diverse as research, 21st Century
those that are not normal and result eldercare and rehabilitation.
in vision impairment. To maintain ● Increased Risk of Falls:
functioning and quality of life, In this issue of Aging & Vision, we A Consequence of
older adults must learn to adapt offer gerontological professionals Vision Impairment
to changes in visual status, and information about safe travel
not let them reduce mobility or for older adults with vision loss. ● Loss of Vision in
increase their risk of falls. Dr. Eli Peli and Henry Apfelbaum, Later Life: A Different
from The Schepens Eye Research Perspective
Having the freedom and Institute, introduce exciting research
independence to get around in the field of low vision mobility Read Aging&Vision
safely — to perform daily tasks, with revolutionary vision devices online at:
visit friends or keep medical to address mobility problems. www.lighthouse.org
appointments, for example — Dr. Rein Tideiksaar, an expert
is one of the most crucial factors in fall prevention, provides an
in adapting well. Riding public overview of how vision impairment
transportation, detecting curbs and influences the risk of falls in
crossing streets are all activities an older population, along with
that older adults with impaired fall prevention strategies. And
vision may need help relearning to Martin Yablonski, Clinical Director
increase independence and safety. of Orientation and Mobility at
Taking advantage of training Lighthouse International,
and support from orientation underlines the importance of vision
and mobility specialists, as well rehabilitation — in particular,
as keeping informed of the orientation and mobility training —
latest developments in mobility in restoring functioning and
research, can assist older adults — quality of life for older adults.
and their families — in taking
control and adapting successfully Cynthia Stuen, DSW, Senior
to life with vision loss. Vice President for Education,
Lighthouse International

Low Vision Mobility Research in the 21st Century

by Eli Peli, MS, OD, and Henry Apfelbaum, AB

While difficulty reading may Central Field Loss (CFL) down slightly. The telescopes,
be the first thing that comes to Age-related macular however, do add weight to
mind when thinking about living degeneration reduces central, spectacles and are rejected often
with low vision, it is mobility detailed vision — often to the because of their cosmetic impact.
that represents a major problem point that reading is difficult, The Low Vision Rehabilitation
for most people with impaired or impossible, without Laboratory is developing a
vision. Even those normally magnification. Such loss new telescope, the “in-the-lens
considered to have few problems generally does not pose a telescope,” which uses mirrors
with mobility — people with age- mobility problem when walking, embedded within the spectacle
related macular degeneration, as the remaining peripheral lens itself to create an optical
for example — frequently are fields provide adequate warning path long enough to provide
mobility impaired. While they of impending obstacles and adequate magnification
usually can walk satisfactorily stumbling blocks. (see Fig. 1). These telescopes
from place to place, they However, loss of central also should permit the user to
frequently struggle with driving. visual detail can restrict the see both the magnified view
ability to drive, because it can and the unmagnified view at
The Low Vision Rehabilitation be hard to read road signs. the same time.
Laboratory at The Schepens Eye Small telescopes attached to
Research Institute, an affiliate spectacles above the normal While bioptic telescopes can,
of Harvard Medical School, has center of gaze — in the “bioptic” in principle, add to the number
a number of projects underway position — can help; the wearer of years a person with CFL
to address mobility problems gets a magnified view of road can drive safely, state driving
among older adults with low signs by tilting his/her head regulations regarding their use
vision. These involve basic and vary greatly. A newly published
applied research in partnership Fig. 1: in-the-lens telescope
with companies that help the
Institute develop novel vision
aids, as well as with a number
of other academic organizations
that assist in the evaluation of
these aids. Aids fall into two
major categories: those for people
with central vision loss; and those
for people with reduced peripheral
visual fields, often caused by
retinitis pigmentosa, glaucoma or
stroke. We then test these aids
under real-world and simulated,
virtual environment conditions.

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book by Dr. Eli Peli, Driving Peripheral Field Loss (PFL) on his/her right clearly and
with Confidence: A Practical Peripheral field loss can occur as see nothing to the left (or vice
Guide to Driving with Low a result of retinitis pigmentosa versa). We have developed new
Vision (World Scientific, River (RP), glaucoma or brain injury, spectacle-mounted prism devices
Edge, NJ), surveys the vision such as trauma or stroke. In the for both types of field loss.
requirements and acceptable case of RP or glaucoma, there
aids for drivers in each of the can be a fairly symmetrical For tunnel vision, two prisms
50 states and the District of concentric peripheral reduction replace one of the spectacle
Columbia. Remarkably, no in vision (tunnel vision), lenses while the other lens
two states have identical although central vision and carries a normal prescription.
requirements. Some allow the acuity can remain good. The prisms are arranged
use of bioptics while others Frequently, this type of loss symmetrically, so that one
forbid it, and the variations with is accompanied by a reduction brings into view portions of the
respect to peripheral field loss in night vision. left periphery while the other
are even wider. The book is brings into view parts of the
designed to help people with Vision loss due to brain injury right periphery. Fig. 2 (below)
low vision, as well as their generally affects just one half illustrates the increase in visual
doctors and lawmakers, decide of the field of view, with a field this provides. With the
on a rational basis when it is sharp line of demarcation increase, however, there is
acceptable to drive, and how between the right and left sides confusion — at any time,
vision aids affect that decision. (hemianopia). When looking the two eyes see entirely
straight ahead, a person with different portions of a scene.
To evaluate existing and new hemianopia may see everything
vision aids, we are testing their (continued on page 8)
use by drivers with low vision,
both in a “virtual reality” driving
simulator, as well as in the real
world — on real streets in
actual traffic — using specially
modified cars and specially
trained instructors. Needless
to say, ensuring safety during
real-world tests and getting
permission from the authorities
to carry them out was a
significant challenge that we
have now overcome. On-road
tests will be conducted in the
coming year in Rhode Island,
Alabama and The Netherlands.

Fig. 2: increased visual fields for RP Aging&Vision

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Loss of Vision Mobility Research in the 21st Century
(continued from page 3)

Tests currently underway are College, real-world walking tests For hemianopia, small prisms
helping us determine how well in a crowded shopping mall and placed on one spectacle lens
the brain can deal with this at a nearby intersection. In our above and below the normal
situation and how effective it lab, we created a virtual model view bring in some of the field
will prove. of the same mall and show from the blind hemisphere.
its image on a rear-projection Below, Fig. 4 shows such
While driving may be possible screen in front of a treadmill spectacles, while Fig. 5 shows
for people with moderate (see Fig. 3). When a person the resulting field improvement.
symmetric PFL, driving is out walks on the treadmill, we use
of the question for people with head and eye tracking to control While many satisfied people
advanced loss. When vision is what is seen on the screen and with hemianopia suggest that
restricted to less than 20 degrees to determine exactly what the this approach is helpful to
or so, the primary concern is person is looking at. This will them, we are completing a
walking, not driving. This is let us know if obstacles are study to assess adaptation to
the condition for which the noticed by chance or through the spectacles, as well as the
symmetrical prisms are the use of the prisms. functioning of subjects while
primarily suited. To test walking in a shopping mall
them, we have established, In the case of hemianopia, our and attempting to cross a
in collaboration with Boston studies have progressed further. busy intersection.

Fig. 4: hemianopia spectacles

Fig. 3: virtual mall Fig. 5: increased visual fields
for hemianopia

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Losing the ability to drive is of made in making these devices This work is partially funded
great concern for many people comfortable and cosmetically by grants from the National
with hemianopia, especially acceptable (see Fig. 7). Institutes of Health.
because many also suffer from
paralysis on the affected side. In summary, we believe that Eli Peli, MS, OD, Senior Scientist,
Tests soon to be commenced creative research, design, The Schepens Eye Research
on the road and with a driving development and testing on Institute, and Associate Professor
simulator will assess the value many fronts will lead to of Ophthalmology, Harvard
of this hemianopia prism device devices that will relieve Medical School; Henry
for driving. some of the significant visual Apfelbaum, AB, Research Analyst,
impediments to mobility The Schepens Eye Research
Video-Augmented Vision among older adults. Institute, Harvard Medical School
In addition, we are investigating
the use of tiny spectacle-
mounted video cameras and
displays to mitigate the loss of
peripheral vision. A wide-field
“minified” image can be
overlaid on the normal view
seen through one or both
spectacle lenses (see Fig. 6).

The minified view provides Fig. 6: minified context
context for orientation and
safety, while the remaining
normal vision provides the
resolution needed to fill in
the details. The video image
can be processed to show a
cartoon-like version of the
scene, by detecting and
presenting just the edges
of objects in view. This type
of presentation makes it easier
to distinguish the normal and
minified views, and reduces
the interference of one view
with the other.

To aid night vision, we are Fig. 7: video-augmented spectacles
experimenting also with
video cameras that operate
in very low light conditions.
Significant progress has been

9 Aging&Vision