The most widely accepted definition of blindness is central visual acuity of 20/200 or less in the better eye with a correcting lens, or whose visual acuity is better than 20/200 with a restricted central field of vision of no greater than 20 degrees.
Almost 1% of the U.S. population is blind and almost 2% of individuals have low vision. The leading cause among White Americans is age-related macular degeneration (54%), whereas cataracts and glaucoma lead the way among Black Americans (60%). Two-thirds of legally blind people have sight of various degrees. Some can distinguish only the difference between light and darkness, whereas others see vague shapes and patterns as if a thick fog were always in front of their eyes. Still others have peripheral sight and see the world around the edges of a blank or distorted area in the center of their vision (macula); they do not see the whole shape of anything if they look directly at it, but by shifting their eyes slightly to one side or up and down they see an image, although not with the detail of the normal macula. Others have no peripheral vision, but normal central vision.
In the visually impaired population, the degrees and different types of vision loss are almost as varied as the people themselves. It is estimated that among blind individuals in the United States and Canada, less than 10% are totally blind (with no light perception). Nonlegally blind but visually impaired individuals outnumber those who are legally blind. The Eye Diseases Prevalence Research Group concluded that approximately one in 28 Americans over the age of 40 years is affected by low vision or blindness, and that by 2020, the number of blind and low-vision persons in the United States will increase by 70% to 1.6 million. This study used data on blindness as defined by the World Health Organization (WHO) (<6/120 [<20/400]) and by the United States (<6/60 [<20/200]) and, for low vision, defined as vision in the better-seeing eye of less than 20/40.
A resolution adopted by the International Council of Ophthalmology, held in Sydney, Australia, April 2002, recommended to the world vision community the use of the following terminology to describe visual loss:
Blindness. To be used only for total vision loss and for conditions in which individuals have to rely predominantly on vision substitution skills.
Low vision. To be used for lesser degrees of vision loss, so individuals can be helped significantly by vision enhancement aids and devices.
Visual impairment. To be used when the condition of vision loss is characterized by a loss of visual functions (such as visual acuity, visual field, etc.) at the organ level; many of these functions can be measured quantitatively.
Functional vision. To be used to describe a person’s ability to use vision in activities of daily living (ADL); presently, many of these activities can be described only qualitatively.
Vision loss. To be used as a general term, including both total loss (blindness) and partial loss (low vision), characterized either on the basis of visual impairment or by a loss of functional vision.
Vision impairment and blindness are feared by most people throughout the world. Seventy percent of Americans older than age 45 years fear blindness more than losing a limb, needing a wheelchair, or deafness. When patients or families of affected patients hear the word “blindness,” they think of loss of all vision, darkness, and gloom. Telling a patient or a parent of a child that he or she is losing vision should therefore be handled with sensitivity, knowledge, and hope. Options for rehabilitation for the patient must be introduced. The patient and family should be expected to grieve for their loss and we as professionals need to understand the grieving process and accept and support it. These families and patients must be given the opportunity to see there is hope for their independence and for attaining and maintaining meaningful lives, education, and jobs.
Partial sight and blindness
When patients are classified as legally blind, they have not always lost all of their visual function. In the United States, blindness is defined as reduction of central visual acuity to no more than 20/200 in the better eye with a correcting lens or limitation of the central field of vision to less than 20 degrees at its widest diameter. The WHO defines blindness as visual acuity less than 20/400. The definitions of blindness used by the WHO and the United States are intended as legal classifications and they do not necessarily convey important functional information. Most patients classified as legally blind can still distinguish between objects, can read with low-vision aids, and maintain their independence with visual aids and training; a smaller number can distinguish only the difference between light and darkness. Low vision is an impairment that cannot be corrected by medicine, surgery, or conventional aids and interferes with functional vision. Many people who are not legally blind are visually impaired and need low-vision rehabilitation.
Most people who are legally blind have some sight. However, it is inaccurate to label a visually impaired person as blind. An individual with sight can learn to use that residual vision in many ways, using a variety of optical devices and computerized reading machines. No one with sight is blind in the sense of having to use alternative nonvisual methods exclusively as the primary mode of functioning. For this reason, no one should be advised to learn to read Braille if he or she can read type, even though classified as legally blind. More than 90% of the legally blind children between 7 and 17 years of age attend regular school. Low-vision aids and computers make this possible.
Braille is probably useful when a person has profound loss of vision (≤5/200) and cannot read type, or read fast enough, with a closed-circuit television (CCTV) or strong magnifier. If possible, children with profound vision loss should be taught print letters and numerals to aid visualization of text, even if they eventually have to switch to Braille.
Recent vision loss
In most instances, it is the ophthalmologist who is responsible for telling a person that he or she has a permanent loss of vision. Most authorities in the field of rehabilitation believe the person should be informed as early as possible once the diagnosis has been made. The sooner the disability is faced and accepted, the sooner the reality of vision rehabilitation can be accepted. The practice of prolonging hope of vision restoration not only impedes effective rehabilitation, but also delays facing reality.
Although it is important for the ophthalmologist to present the diagnosis in a candid and factual manner, it is just as essential for the practitioner to appreciate the emotional effect of such information. The doctor should provide a supportive environment in which the person is allowed time to ask questions, as well as be given information about community rehabilitation resources.
For most individuals, any loss of vision arouses an emotional response, usually fear of blindness. Depression is a normal response to becoming dependent and having to rely on others for help in basic living activities. Young adults fear loss of a job; older adults fear financial dependence, isolation, and loss of their friends and community.
Myriad repeated frustrations occur in the daily lives of the totally blind that accentuate the dependency of the condition. Maintaining a job and personal life becomes a feat in itself. The routines that the sighted do automatically and without thought must be deliberately learned, step by step, by the blind. For example, the blind person must learn how to eat all over again. If the portions on a plate are not placed in a certain location, the blind person must explore the plate with a fork to discover where the food is placed.
Simple tasks can arouse feelings of insecurity, fear, and anxiety, especially when they have to be performed in public. Blind people may be afraid of making mistakes and of being clumsy and awkward for fear that they will become an object of attention. It is these little things—such as eating out in public, combing the hair or shaving, putting on makeup, or setting down a glass of water without knocking it over—that the blind must be able to learn to do with confidence. One of the first decisions to be made is whether the person would be safer learning long-cane travel or whether a guide dog would be more compatible with the individual’s temperament. Each method has its adherents, advantages, and disadvantages; it is a highly personal choice.
Totally blind people may choose to withdraw into a familiar and unchanging environment that can be controlled with their visual incapacity. If they withdraw, they will be safe from physical harm and public ridicule, but limited in thoughts and actions. The other extreme is to tackle the problem head on, that is, to ignore the disability and continue with life despite the inconveniences, dangers, and hardships, learning in a specialized agency or organization for the blind how best to adapt to life without sight. The most desirable reaction is one that balances the disability with new ability and redirects interests, skills, and strengths so that the visual need in selected activities is minimized. The physician can be supportive of this reorientation by referring the blind person to trained rehabilitation personnel who can transmit the new skills to help the individual move toward physical and psychologic adjustment.
Ophthalmic assistant’s role
The ophthalmic assistant will encounter in his or her daily work individuals who have a variety of different vision impairments, including blindness. The assistant should be familiar with the methods used to provide orientation to those with visual disabilities and to facilitate their mobility.
On first meeting a blind person, one should introduce oneself. The assistant should always offer his or her arm to the blind person. With a hand lightly on the assistant’s arm, the patient feels the body movement and, because the assistant is slightly in front, the patient will have a feeling of confidence with each step. To be propelled from behind can be most awkward and unnerving. The assistant should be sure to ask a blind person if he or she needs help because the need for assistance should not be assumed without question. When you reach the examination chair, tell the patient where the chair is and place his hand on the chair so that he can position himself properly. Naturalness, kindness, and inherent human respect result in the most successful relationships and avoid an overdose of assistance, which makes a handicap more noticeable and damages the value of the assistant’s role.
The assistant should realize that he or she should go to the patient to escort the latter to the examination room, rather than expecting the patient to navigate the office alone. Also any paperwork to be completed by the patient should be handled by either the assistant or office personnel in a private setting. If a blind person has been guided to a place and is to be left alone, he or she should first be informed about the surroundings. It is also desirable, under such circumstances, to establish some position of safety and orientation, such as a table, chair, or wall, and to let the patient know if the door will be left open, so the person can call out for assistance if needed and be assured that someone will return shortly to check on the patient.
Because most patients with visual loss have normal hearing, medical personnel should avoid talking loudly to them. A patient with a visual impairment does not want to have his history discussed out loud in a waiting room any more than a sighted person would. You should not assume that the person accompanying the visually impaired patient is the one to whom questions of a sensitive nature should be directed. It is possible that this person is a neighbor or taxi driver and not someone with whom the patient wants to discuss private information. Visually impaired patients deserve the same courtesy as sighted patients.
The ophthalmic assistant should be aware of the thin line between giving someone assistance and making him or her feel helpless. Many blind people are quite proud of the many functions they can perform for themselves. They do not like having their disability emphasized and their dependency magnified. The assistant can ask the patient, in a quiet voice, if he or she can help him with this or that and let the patient make the decision about the degree of assistance wanted.
The ophthalmic assistant should avoid discussing with patients the status of their eyes, the state or federal assistance they can expect, or the details of the facilities available for them. Each of these areas should be handled by professionals trained in their fields. The assistant should also avoid giving false hope to patients by casually mentioning the miracles being achieved every day in the fight for sight.
Blind people should not be regarded as unimportant or incompetent. Patients should be asked questions directly, not through a second party. Conversation should never be allowed to flow around or through them as though they did not exist. They should be treated as individuals without sight, not as ones without insight.
The blind child
Congenitally blind children, unlike some of their adult counterparts, have no recollection of the visual world to assist them. Without this visual memory, blind children must learn about the world by being exposed to the environment and provided with the opportunity to explore it through other senses. Although parents know their child best, early intervention by child development specialists who have training in visual impairment can offer additional support to parents and assist them with encouraging their child’s normal development. Other professionals who can offer support with the habilitation needs of blind children include orientation and mobility specialists and life skills instructors. These personnel are trained to assist blind children and their families with the development of daily living skills and the attainment of safe independent travel skills.
The young child who does not have a visual memory may have to be physically shown and encouraged to de-velop skills, such as creeping, walking, holding a spoon, and drinking from a cup. The blind child who has never seen these activities cannot rely on visual modeling as a learning tool. Parents of blind children must be patient and firm, allowing their child the opportunity to succeed by independently doing a task, as well as permitting the child to fail at times and learn from his or her mistakes.
It is important that some routine be established in the home to assist the blind child with understanding his or her environment. For example, it is easy for a totally blind child to confuse day with night; thus the routine of going to bed is important. Because bedtime is not accompanied by a change of light, a preliminary quiet period can be substituted. The blind child’s language and concept development can be facilitated by bringing the child into direct association with the object or action while the appropriate words are being used. This helps the child to acquire a meaningful conceptual base.
Many congenitally blind children develop mannerisms, such as rocking, touching and rubbing their eyes, or waving their hands. These and other repetitive motions are known as blindisms. Early intervention with blind children focuses on trying to help the child prevent these blindisms from developing. Once blindisms are established, diminishing them may require persistent effort on the part of the blind person to correct them.
It is estimated that up to 60% of young blind infants and preschool children in North America have additional motor and cognitive disabilities. One reason for this is the greater ability of modern medicine to save low-birthweight infants. Although many of these infants may be perfectly normal, premature infants with very low birthweights (<750 g) tend to have a greater incidence of disability. Blind children with additional disabilities require either a transdisciplinary team approach or a special school to effectively meet their diverse and unique habilitation needs.
Although most blind children receive their education through local schools in an integrated educational setting, the totally blind child requires some form of educational support services to assist with meaningful learning in the integrated classroom. Residential schools for blind children still exist in some areas, thus allowing families and school placement personnel choices and options to best meet the educational needs of the individual child.
One form of written communication the blind child may use is Braille, a system of raised dots on paper read by touching them with the ends of the fingers ( Fig. 44.1 ). Although modern technology presents blind children with more communication options, the importance of Braille has not diminished as a tool for literacy.