Visual Mobility Aids for Patients with Night Blindness
SUMMARY
AGENCE D’ÉVALUATION DES TECHNOLOGIES
ET DES MODES D’INTERVENTION EN SANTÉ
41
December 2006
Report prepared for AETMIS by
Valérie Martin
Visual Mobility Aids for Patients with Night Blindness
Summary
This summary was translated from an offi cial French publication of the Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS). Both the original report, titled Aides visuelles à la mobilité des personnes atteintes de cécité nocturne and the English summary are available in PDF format on the Agency’s Web site.
SCIENTIFICREVIEW
Jean-Marie R. Lance, Economist, Senior Scientifi c Advisor Véronique Déry, General and Scientifi c Director
François-Pierre Dussault, Scientifi c Advisor and Coordinator of the Technical Aids and Rehabilitation Unit TRANSLATION
Mark Wickens, Ph.D., Certifi ed Translator EDITORIALSUPERVISION
Suzie Toutant PAGELAYOUT
Sylvie Houle
BIBLIOGRAPHICRESEARCH
Denis Santerre COORDINATION
Lise-Ann Davignon
COMMUNICATIONSANDDISSEMINATION
Diane Guilbaut Richard Lavoie
For further information about this publication or any other AETMIS activity, please contact:
Agence d’évaluation des technologies et des modes d’intervention en santé 2021, Union Avenue, Suite 10.083
Montréal (Québec) H3A 2S9 Telephone: 514-873-2563 Fax: 514-873-1369
E.mail: aetmis@aetmis.gouv.qc.ca www.aetmis.gouv.qc.ca
How to cite this document:
Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS). Visual Mobility Aids for Patients with Night Blindness. Report prepared by Valérie Martin. (AETMIS 06-09). Montréal: AETMIS, 2006.
Legal deposit
Bibliothèque et Archives nationales du Québec, 2006 Library and Archives Canada, 2006
ISBN 2-550-48413-4 (printed French edition) ISBN 978-2-550-48413-4 (printed French edition)
ISBN 2-550-48752-4 (PDF) (French edition ISBN 2-550-48414-2) ISBN 978-2-550-48752-4 (PDF) (French edition ISBN 978-2-550-48414-1)
© Gouvernement du Québec, 2006.
This report may be reproduced in whole or in part provided that the source is cited.
The mission of the Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS) is to help improve the Québec health-care system. To this end, it advises and supports the Minister of Health and Social Services and decision-makers in the health-care system with regard to the assessment of health services and technologies. The Agency makes recommendations based on scientifi c reports assessing the introduction, diffusion and use of health technologies, including technical aids for the disabled, as well as the methods of providing and organizing services. The assessments examine many different factors, such as effi cacy, safety and effi ciency, as well as ethical, social, orga- nizational and economic issues.
i
M ISSION
M
EXECUTIVE
Dr. Juan Roberto Iglesias,
President and Chief Executive Offi cer Dr. Véronique Déry,
Chief Executive Offi cer and Scientifi c Director Dr. Reiner Banken,
Deputy Chief Executive Offi cer, Development and Partnerships Dr. Alicia Framarin,
Deputy Scientifi c Director Jean-Marie R. Lance,
Economist, Senior Scientifi c Advisor
THE BOARD
Dr. Jeffrey Barkun,
Surgeon, Royal Victoria Hospital, MUHC, and Director, Department of General Surgery, Faculty of Medicine, McGill University, Montréal
Dr. Marie-Dominique Beaulieu,
Holder of the Dr. Sadok Besrour Chair in Family Medicine, CHUM, Full Professor, Faculty of Medicine, Université de Montréal, and Researcher, Evaluative Research Unit, Hôpital Notre-Dame, CHUM, Montréal
Dr. Sylvie Bernier,
Director, Organization of Medical and Technological Services, MSSS, Québec
Dr. Suzanne Claveau,
Microbiology and Infectious Disease Specialist, Hôtel-Dieu de Québec, CHUQ, and Associate Clinical Professor, Faculty of Medicine, Université Laval, Québec
Dr. Serge Dubé,
Surgeon, Director of the Surgery Program, Hôpital Maisonneuve- Rosemont, and Vice-Dean of Professorial Affairs, Faculty of Medicine, Université de Montréal
Roger Jacob,
Biomedical Engineer, Coordinator, Capital Assets and Medical Equipment, Agence de la santé et des services sociaux de Montréal Dr. Michel Labrecque,
Professor and Clinical Researcher, Family Medicine Unit, Hôpital Saint-François d’Assise (CHUQ), Québec
A.-Robert LeBlanc,
Engineer, Full Professor and Program Director, Biomedical Engineering Institute, Université de Montréal, and Assistant Director of Research, Development and Utilization, Hôpital du Sacré-Cœur de Montréal Research Centre, Montréal
Esther Leclerc,
Registered Nurse, Director of Nursing, Hôpital Saint-Luc, CHUM Dr. Jean-Marie Moutquin,
Obstetrician/Gynecologist, Director of Research and Director, Department of Obstetrics and Gynecology, CHUS, Sherbrooke Dr. Réginald Nadeau,
Cardiologist, Researcher, Hôpital du Sacré-Cœur de Montréal Research Centre, and Emeritus Professor, Faculty of Medicine, Université de Montréal
Johane Patenaude,
Ethicist, Associate Professor, Department of Surgery, Faculty of Medicine, Université de Sherbrooke, and FRSQ Research Scientist Dr. Simon Racine,
Director, Regional Direction of Medical, University and Physical Health Affairs, Agence de la santé et des services sociaux de la Capitale-Nationale, Québec
Lee Soderstrom,
Economist, Associate Professor, Department of Economics, McGill University, Montréal
ii
N OTE TO READER
The Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS) makes recommendations on the introduction, diffusion and use of health technologies and technical aids for disabled persons, as well as the modes of providing and organizing services.
The type of scientifi c studies carried out in each of these areas differs in several respects.
For example, studies published in the area of technical aids are seldom randomized, and controlled studies, if any, use narrow quantitative variables and report qualitative data (e.g., on satisfaction) that are diffi cult to interpret. Indeed, the use of a technical aid is part of a rehabilitation intervention approach that should take into account personal and environmental factors that lead to handicap situations.
For these reasons, when the Agency issues an advice on a technical aid, it modulates its requirements in terms of the type and quality of the scientifi c evidence and gives, when making its recommendations, important weight to the contextual elements of individual and organisational management associated with rehabilitation strategies.
iii
f OREWORD
f
Visual Mobility Aids for Patients with Night Blindness
N
ight blindness is the inability of the eye to adapt to reduced illumination, therefore leading to a complaint of not being able to see in the dark. It can be caused by degenerative diseases of the retina, such as retinitis pigmentosa, or by other pathologies that affect visual adaptation to darkness. Individuals with night blindness experience serious orientation and mobility problems in conditions of poor illumination, and the currently available aids⎯the white cane and the guide dog⎯do not succeed to ensure their safety during travel in such conditions.Night vision aids (NVAs) or night vision goggles (NVGs) may facilitate their mobility. This technology, which was originally developed for military purposes, amplifi es ambient light to permit vision in conditions of poor illumination. There is another night vision device, the wide-angle mobility light (WAML), which provides a large and very intense beam of light. Rehabilitation centre professionals and associations representing the visually impaired asked the Ministère de la Santé et des Services Sociaux (MSSS) to consider including NVAs in the Visual Devices Program, which is administered by the public health insurance plan. The MSSS therefore asked the Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS) for a report on night vision assistive devices.
This assessment concludes that night vision devices, such as the WAML and NVAs, can, despite certain limitations, effectively help certain individuals with night blindness by making it safer for them to travel in low-illumination conditions. On the other hand, NVGs are still in the experimental stage. In order for these night vision assistive devices to be as useful as possible, they should be allocated and their use monitored by orientation and mobility specialists within the context of a personalized intervention. The intervention should include, among other things, a pre-allocation assessment of the needs of the user, appropriate training, a trial period with the device, and regular follow-up assessments. Problems accessing these different devices in Québec could be resolved with a public program such as the Visual Devices Program. Lastly, this report emphasizes the need to continue efforts to collect and share data in order to better identify the conditions for optimal night-vision aid utility.
In order for public visual impairment rehabilitation services to better meet the needs of individuals with night blindness, AETMIS recommends that the eligibility requirements of the Visual Devices Program take into account all of the aspects of vision affected by night blindness; that the MSSS, after consulting its partners, make NVAs and mobility lights accessible to individuals with night blindness and, when the necessary conditions are met, take steps to include these devices in the list of aids available in the Visual Devices Program; that the allocation of these devices and the monitoring of their use be supervised by professionals who work in Québec rehabilitation facilities; and that these facilities collect data on the clinical utility of night vision devices and draw the necessary conclusions from these data in order to improve the services offered.
In submitting this report, AETMIS wishes to contribute to decision-making concerning policies and programs intended for the visually impaired.
Dr. Juan Roberto Iglesias
President and Chief Executive Offi cer
iv
A CKNOWLEDGEMENTS
A
This report was prepared by Valérie Martin, M.Sc. (Health Technology Assessment and Management), research consultant at the Agence d’évaluation des technologies et des modes d’intervention en santé (AETMIS).
The report is based on a review of scientifi c studies and on interviews conducted by Yves Jalbert, Ph.D., within the framework of a contract granted by AETMIS to the Institut Nazareth et Louis-Braille.
The Agency also wishes to thank the external reviewers for their numerous comments, which improved the quality and contents of this report:
Dr. Jacques Gresset, O.D., Ph.D., Director and Full Professor, School of Optometry, Université de Montréal.
Dr. Jean-Paul Lachance, O.D., M.Sc., Institut de réadaptation en défi cience physique de Québec, Quebec City.
Dr. Nieves Rodriguez-Hernandez, Ophthalmologist and a master’s student in Health Technology Assessment and Management, Université de Montréal.
Xavier-Michel Lucas, Occupational Therapist, D.E., Centre Hospitalier Universitaire de Nîmes (France).
CONFLICT OF INTEREST None declared.
v
S ummary
S
Issue
Night blindness is the inability of the eye to adapt to reduced illumination, therefore leading to a complaint of not being able to see in the dark. It can be caused by
degenerative diseases of the retina, such as retinitis pigmentosa, or by other pathologies that affect visual adaptation to darkness. People with night blindness can use a white cane or a guide dog. These aids, however, are not suffi cient to ensure their safety during travel in conditions of poor illumination. This is why various researchers and professionals who work with individuals with this condition have explored other alternatives over the years, including attempts to adapt existing technologies, such as night vision aids and night vision goggles, and even a scuba diving light.
Night vision aids (NVAs) use a technology that was developed for military purposes. It looks like a small video camera and is handheld or can be mounted on the head with a system of straps. Light, even very weak, received by the ocular objective is channelled to an image amplifi er, which makes it visible to the naked eye on a small video screen placed in front of the eye. The image, which is monochromatically green, does not give normal depth or colour perception. NVAs can be used occasionally at specifi c times or in specifi c places when travelling. Night vision goggles (NVG) work in a similar manner and are worn like eyeglasses or are mounted on a helmet. The wide-angle mobility light (WAML) is a high-intensity lamp originally designed for scuba diving that produces a large and very intense beam of light.
Rehabilitation centre professionals and associations representing the visually impaired asked the Ministère de la Santé et des Services Sociaux (MSSS) to consider including NVAs in the Visual Devices Program, which is administered by the Régie de l’assurance maladie du Québec (RAMQ). The purpose of this report is to assess, based on a review of the scientifi c literature and an examination of the situation in Québec regarding assistance for people with night blindness, the clinical utility of night vision devices in improving orientation and mobility; the conditions for supervising the allocation of these devices and the monitoring of their use; and the advisability of including them in the Québec’s Visual Devices Program.
Methods
A scientifi c literature search was conducted in different databases, including MEDLINE (PubMed) and the INAHTA (International Network of Agencies for Health Technology Assessment) database. The report provides a complete review of the relevant studies that were selected. In addition, a number of web sites were consulted in order to identify the commercially available products and the resources available for people with night blindness. As well, interviews were conducted to describe the situation in Québec regarding the use of night vision assistive devices.
vi
Results
The analysis of the scientifi c literature confi rms that orientation and mobility are seriously impaired in people with night blindness. However, these problems vary from person to person, and, for a given individual, vary over time with changes in his/her visual and overall health and with his/her lifestyle. Night vision devices have been little studied in the scientifi c literature, since only nine relevant articles were identifi ed.
Studies of NVAs and the WAML have clearly shown that they are of some clinical utility, although it cannot be generalized to all individuals with night blindness. In low- illumination conditions, these assistive devices reduce the number of stumbles and contacts with obstacles, for example, and improve travel time or walking speed. The WAML seems to be more effective than NVAs. As for NVGs, their use by night-blind individuals is still experimental, given that two of the four relevant studies concerned prototypes. Even if these scientifi c studies are of weak methodological quality, they are presently the only ones available, and the chances of conducting better studies are slim due to the low prevalence of night blindness and to diffi culty obtaining some of the devices of interest.
The qualitative studies involving NVA and WAML users usually report a positive evaluation of these devices in that they facilitate travel and improve the safety and number of trips. In addition, users indicate that these devices can be useful for other daily or work-related activities, such as communicating in sign language. These studies also reveal some limitations: the comfort and ease of handling of NVAs are unsatisfactory, and the WAML poses problems in terms of comfort, battery operating time, and susceptibility to mechanical failures. It should, however, be stressed that professionals are divided in their opinions of the WAML’s utility. Unlike the white cane, NVAs and the WAML do not identify the user as having a visual impairment, but these aids can prompt questions or reactions from pedestrians or others nearby.
NVA technology was the subject of a 3-year experiment at Québec’s Institut Nazareth et Louis-Braille (INLB). The experience was described as positive: NVAs improved orientation and mobility and enhanced the independence and safety of night-blind individuals. These fi ndings are supported by a more in-depth qualitative study involving six NVA users enrolled at the INLB. The study concludes that these devices made it easier and safer for them to travel.
Given the uncertainties concerning who is most likely to benefi t from night vision devices and the variation in their utility over time, they should be prescribed on a personalized basis by a qualifi ed professional according to individual needs. The assessment should take into account the person’s disease, orientation and mobility abilities, and motivation, and the circumstances in which the device is intended to be used, which will make it possible to better defi ne his/her needs and to guide the choice of device. Once the aid is allocated, adequate training should be provided by an orientation and mobility specialist in a nighttime setting. After the allocation, a follow- up would determine if it is having a real effect on the individual’s mobility performance and is making it easier for him/her to carry out his/her activities of daily living in low- illumination conditions. The follow-up assessments should continue on a regular basis to take into account changes in the individual’s condition.
An examination of the situation in Québec regarding assistance for the visually impaired revealed that not all individuals with night blindness who need visual aids have access to the Visual Devices Program administered by the RAMQ, given that the eligibility requirements do not take into account all the aspects of vision affected by night blindness.
vii Furthermore, access to NVAs is not easy, for they are very expensive and are presently offered only to a limited clientele of the INLB, which has a fl eet of 13 devices through the INLB’s foundation. The mobility light is presently not as well-known and is less preferred, even if it is inexpensive. It would be advisable for orientation and mobility specialists to further explore this alternative and to minimize, through training, its limitations, mainly the possibility of causing dazzle to others. An inventory of the devices presently available or which could become available in Québec should be compiled in collaboration with rehabilitation centre professionals, with special attention given to the basic requirements.
A number of uncertainties still surround the clinical utility of these devices because of the methodological weaknesses of the reviewed studies and because of the observations of experts in Québec. Collecting clinical data on the allocation of NVAs and mobility lights and on the monitoring of their use in Québec could help better determine their utility. These data would serve to guide future decisions concerning access to these devices, who is most likely to benefi t from them, and the best ways to enable orientation and mobility specialists to better help individuals with night blindness.
Conclusions
Night vision devices, such as the mobility light and NVAs, may prove useful to certain individuals with night blindness who have problems travelling in low-illumination conditions. Night vision assistive devices should be allocated and their use monitored by orientation and mobility specialists as part of a personalized intervention that includes a pre-allocation assessment of the needs of the user, appropriate training, a trial period with the device, and regular follow-up assessments. To adequately meet the needs of all individuals with night blindness, access to night vision assistive devices (NVAs and mobility lights) should be provided and facilitated within the framework of a public program such as Québec’s Visual Devices Program. Lastly, efforts to collect and share data in order to optimize the utility of night vision assistive devices should continue.
Recommendations
In order for public visual impairment rehabilitation services to better meet the needs of individuals with night blindness, AETMIS recommends that:
1) The eligibility requirements of the Visual Devices Program take into account all the affected aspects of vision in night-blind individuals;
2) The Ministère de la Santé et des Services Sociaux, after consulting its partners, make NVAs and mobility lights available to people with night blindness and, when the necessary conditions are met, take steps to include these devices in the list of aids available in the Visual Devices Program;
3) The allocation of these devices and the monitoring of their use be supervised by professionals working at Québec rehabilitation facilities, as stipulated in the Visual Devices Program;
4) Rehabilitation facilities that allocate and monitor the use of these aids gather data on the use and effectiveness of night vision devices and draw the necessary conclusions from these data in order to improve the services offered.
