Low Vision Rehabilitation/1ː What is low vision and low vision rehabilitation?/What is low vision?/Vukicevic M. Vision Rehabilitation (2008)
Rehabilitation is a technique that is aimed towards restoring a person’s ability to perform a particular body function, or to perform daily living tasks, when ability to perform a function or task is impaired as a result of disease or disability. Improvement in ability occurs after a person has been trained to utilise new skills to perform these tasks. Rehabilitation techniques can be applied to various areas of the human body that have been affected by disease or disability. This includes the human visual system. Thus, a person with vision loss is able to undertake rehabilitation in order to utilise their remaining vision.
A Brief Historical Overview of Vision Rehabilitation
Vision rehabilitation is a very new concept given that medical practice and research has an extensive history and long standing tradition. The treatment of illnesses in prehistoric civilisations was carried out by magicians and medicine men and most practical and technical healing skills were enveloped in spiritual tradition and cults. As knowledge of human anatomy increased, early civilisations such as the ancient Egyptians, Greeks and Romans further advanced the practice of medicine and treatment of illnesses. The ancient Egyptians developed knowledge into human body functions and insight into the function of the heart, blood and importance of air. In addition, due to their religious-based embalming techniques, they described various organs of the body, particularly the brain. The ancient Greeks were also influenced by religion and whilst their lives were dominated by the Gods and natural phenomena were attributed to their Gods, evidence however exists that Greek physicians exclusively treated people that were ill. One such physician was Hippocrates. Another ancient Greek scholar, Alcamaeon of Croton, was one of the first to operate on the eye and discover that there were links between the organs and the brain. The ancient Romans further advanced the study of medicine and disease. Whilst they learned from the ideas of the Greeks, their main focus was on public health schemes, improving hygiene and controlling diseases (Duke-Elder and Wybar 1961, Sournia 1992, Magotta and Lewis 1996).
Although the ancient Egyptians, Greeks and Romans advanced the study of medicine, medical knowledge in the middle ages stagnated. During this time European scholars concentrated their thoughts on theological issues rather than scientific ones and the Catholic Church dominated medical practice. Diseases were attributed to supernatural causes and common medical illnesses were thought to be punishments from God. In relation to the visual system, anatomists of the time thought that light rays diverged from the eye and the ‘nervus opticus’ transmitted ‘visual spirits’ through the lens.
Whilst the belief existed that diseases were caused by the supernatural, the explorer Marco Polo documented a practical solution to vision difficulties. Upon his return from China in 1270, he reported that convex lenses were being used by the elderly Chinese, in order to read fine print (Corn 1986).
During the Renaissance doctors concentrated on performing surgery on patients and universities were established to provide a scientific basis for teaching medicine. However, due to the delicate nature of the eye it was difficult for anatomists to make advances and great discoveries with regards to the structure and optics of the eye. In 1637 French philosopher, scientist and mathematician, Rene Descartes described the use of a magnifying aid that could assist people with vision impairment (Goodrich and Arditi 1999). This description may possibly be the only documented attempt at vision rehabilitation during this period in history, apart from Marco Polo’s documentation of convex lenses (Duke-Elder and Wybar 1961, Porter 1997). There is very little evidence that there was any attempt to provide treatment or education to persons who were blind or vision impaired during antiquity, the middle ages or even as late as the 17th century.
Whilst limited documents exist regarding vision rehabilitation prior to the 18th century, the study of the anatomy of the eye, in addition to the study of eye disease, continued into both the 18th and 19th centuries. By the end of the 18th century, enlightened humanitarians were convinced that the blind were able to adapt to their surroundings and perform normal tasks of daily living. In 1784 Benjamin Franklin invented bifocals and in this same year the first institution for the blind was founded in Paris by Valentin Huay where blind children were taught to read by touch using raised letters embossed on paper. Similar institutions were later founded in England, Germany and various other European countries (Magotta and Lewis 1996, Porter 1997).
The 19th century heralded major advances in general medicine with the study of bacteria and subsequent development of vaccines. It was at this time that a blind teacher by the name of Louis Braille invented the Braille system of raised coded dots that enabled blind persons to read. It was also in the late 19th century that Helen Keller, a deaf and blind American woman, raised awareness and funds, advocating for the rights of blind persons (Keller 1912). At about this same period in history, Reverend James Miriam established the Victorian Asylum and School for the Blind in Australia. In 1870 the asylum established a vocational training centre for persons with vision impairment. This organisation later became known as the Royal Victorian Institute for the Blind. A student of the institute by the name of Tilly Aston, formed the Victorian Association of Braille Writers and in 1895 founded the Association for the Advancement of the Blind. This association was a fundamental lobby group for persons with vision impairment. The organisation was able to bring about voting rights for the blind in 1902, established nursing homes and a library for the blind in 1909 and 1919 and invented blind cricket in 1922 (Wilson and Wright 1996, Buckrich 2004). The role of these historical figures was fundamental for advocating on behalf of the blind and increasing awareness of their plight. Awareness that rehabilitation could be used to benefit persons with vision impairment was increasing, although it was still underdeveloped.
Significant progress in terms of recognising the benefits of teaching blind persons was made in the early 20th century. Several schools specifically focused on the tuition of blind students and institutions for the blind were founded at this time. Some included the Myope School and the Blind Social Aid and Literary Union in the United Kingdom; the National Society to Prevent Blindness and the Perkins Institute in the United States and the Colne Society in Germany. In addition, the Clear Type Publishing Company published some text books printed in large font (Goodrich and Arditi 1999). It was also in the early 20th century that one author documented various diseases of the eye and described appropriate therapeutic and surgical treatment (Parsons 1930). In this publication Parsons does not discuss any forms of rehabilitation for those with poor visual acuity due to macular disease or other vision problems. Nevertheless, he does describe some symptomatic disturbances of vision such as hemianopia, amblyopia and transient scotomas associated with migraines. Unfortunately, no practical solutions to overcoming poor visual function are reported. He does however devote a brief chapter to the ‘hygiene of vision’ where he includes discussion about optimum candle-luminance required for the task of reading and writing for normally sighted persons in order to avoid eye strain. However, there is no guide to clinicians regarding optimum candle-luminance for persons with low vision or macular disease.
Over a decade after Parsons, another author devoted a small section in his book to “special glasses for optical purposes” (Duke-Elder 1943). Here Duke-Elder describes a new found use for telescopic or Galilean spectacles previously used mainly by jewellers or those involved with industrial work such as linen grading. The telescopes and Galilean spectacles were found to be beneficial to persons with a variety of retinal diseases. He states that “a certain amount of vision can sometimes be obtained by the use of these spectacles” which are arranged in the manner of a Galilean telescope which is comprised of two lenses, one concave and one convex. The distance between the lenses is the difference of their focal length. This design arrangement allows a person to view an enlarged image of a distant object and the size and weight of the telescope is kept to a minimum (Duke-Elder 1943, Duke-Elder and Abrams 1970, Goodrich and Arditi 1999). The development of vision rehabilitation revolved around the use of telescopic lenses and the American Foundation for the Blind had begun supplying these aids as early as 1924.
Although some methods of vision rehabilitation had been described as early as the 1920s, it is difficult to state exactly when modern vision rehabilitation techniques arose. Goodrich reports that vision rehabilitation began in the 1950s with a paper published by New York’s Industrial Home for the Blind (Goodrich 1990). The author maintains that this paper defines rehabilitation as a distinctive discipline within a multi-disciplinary vision rehabilitation service. In addition, Goodrich suggests that this paper describes a service that is consistent with current rehabilitation practice and deserves to be noted historically as the beginning of modern vision rehabilitation. His statements are supported by the fact that this is the first publication outlining vision rehabilitation principles incorporating multi-disciplinary teams. These principles, in addition to the involvement of multi-disciplinary teams in vision rehabilitation, are still considered best practice.
During the 1950s persons with low vision relied upon telescopic loupes to assist them with close work such as reading. These loupes, which were placed in a spectacle frame, involved mounting a Galilean telescope with a convex lens, enabling the user to focus upon a close object. After 1955, inexpensive magnifiers were developed for use by persons with vision impairment. These were originally designed for normally sighted users, for tasks such as looking at stamps, coins and fingerprints or used by jewellery makers, as described earlier (Duke-Elder 1943). The American Foundation for the Blind was instrumental in making these aids commercially available to persons with vision impairment and kept a selection of aids, from which the low vision patient could choose, based upon his or her requirements. It was soon after this that Louise Sloan, a pioneer in vision rehabilitation, published several papers on topics such as using distance low vision aids, optimising illumination, using Closed Circuit Televisions and reading cards (Sloan 1964, Sloan 1969, Sloan and Habel 1973, Sloan 1975, Sloan 1977). At the time of these publications, and almost thirty years after the publication of “The Practice of Refraction” in 1943, Duke-Elder published “Ophthalmic Optics and Refraction” (Duke-Elder and Abrams 1970). In this book, Duke-Elder describes the use of magnifying devices in the form of aids such as hand magnifiers, stand magnifiers and telescopic spectacles for use in aiding the vision of those with disorders of the retina, optic nerve or visual pathway. Duke-Elder also states that magnifiers are of greatest value for those with macular disease. The author does however note that despite their usefulness, many magnification aids are difficult to manage and factors such as patient’s cooperation, intelligence and motivation are of prime importance to a successful outcome with the aid. Duke-Elder points out that magnifying aids are not completely ideal rehabilitation tools. Patients often have difficulty using them due to problems with focusing the aid, or learning to use the aid. This results in poor motivation for reading with such a device.
Whilst there were some publications regarding low vision available from the 1940s until the early 1970s, very little literature specific to vision rehabilitation is accessible. The reason for this is not that pioneering work was not being carried out in the field, but rather that most publications at that time were memorandums, internal publications and personal correspondences between low vision clinicians within and between organisations.
One of the first available books in the area of low vision entitled “The Low Vision Patient” was published in 1970 (Faye 1970). This book evolved from work undertaken at the New York Lighthouse, a support agency for the persons with vision impairment, established in the early 1950s. The publication is an informative guide depicting the important work done by the organisation at the time. It describes innovative rehabilitation methods and treatment offered to the patient, outlining both the medical and optical approach to rehabilitation. In addition, significant emphasis is placed upon methods of accurate vision testing and prescription of low vision aids, including the advantages and disadvantages of these aids, and methods for improving patient compliance and correct use. Apart from advances in optical aid intervention, Faye’s book also introduces a new concept in low vision patient care, that is, the consideration of psychological and social factors of the patients attending the clinic, to which the author devotes an entire chapter.
Faye and her colleagues collected data on 6,000 patients seen by the Low Vision Service of the New York Association for the Blind from 1953 to1968. The largest primary ocular diagnosis of these patients was macular pathology, making up 25% of the total number of patients seen. Apart from the traditional approach of magnification, Faye does not include discussion of ways to approach vision rehabilitation which is specific to patients with macular pathology, despite the fact that these patients made up one quarter of the clinic’s overall patients. Macular pathology is only very briefly mentioned in the book and vision rehabilitation is described as a practical solution, which can be related to patient’s daily life. In addition, broad statements such as “once reassured, those with macular pathology learn to use their peripheral retina, looking at distance objects off centre and reading in the intact area with magnification” are made by the author. Faye does not describe how these patients come to use their peripheral retina nor the extent of their ability to use it. This lack of detailed information and mainly anecdotal data is typical of the literature published at the time. A later publication by Faye discusses rehabilitation for low vision patients, with emphasis on the use of magnification as the standard and widely accepted form of rehabilitation (Faye 1976). As in the previous book, this one published in 1976 only very briefly refers to low vision patients with a central scotoma.
Great importance was placed upon the use of low vision aids in the area of vision rehabilitation in the 1970s. The most likely reason for this emphasis is that magnifying glasses and telescopes had only become commercially available to patients with vision impairment a decade or two previously. Thus most of the publications of the time were concentrated towards the use and development of these aids, including work by authors such as Sloan (1977) and Gerstman and Levene (1974). One such article, published in 1974 by Sloan and a colleague, describes the various characteristics and strengths of magnification aids in addition to methods for correctly prescribing these aids to assist in the rehabilitation of persons with vision impairment (Wells and Sloan 1974). In common with other authors, Wells and Sloan include discussion regarding the advantages and disadvantages of low vision aids but do not discuss any alternative vision rehabilitation strategies.
Despite the fact that the greater part of vision rehabilitation work concentrated on magnification devices and assessment, there were some revolutionary authors of the 1970s who were focusing on alternative forms of vision rehabilitation. This included perceptual vision rehabilitation based upon their clinical experiences with low vision patients (Holcomb and Goodrich 1976, Goodrich and Quillman 1977, Backman and Inde 1979, Lederer and Wulff 1979, Wulff 1979). Backman and Inde, published a manual describing exercises and vision training for persons with central scotomas, nystagmus, decreased peripheral vision and amblyopia. Based upon the authors’ personal and clinical experience rather than through scientific testing, they conclude that the ability to use remaining vision is significantly improved by vision training. In addition the manual offers practical exercises and skills for the low vision user on how to improve residual vision (Backman and Inde 1979).
The 1970s were a very crucial time in the development of vision rehabilitation. This decade heralded a movement towards alternative methods of utilising remaining vision, quite distinct from the conventional use of magnification or optical aids. There were several pioneers of this new method of improving remaining sight for those suffering with a central scotoma caused by age-related macular degeneration or other macular disease, laying an important foundation for further work in the field over the coming decades.
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