Fig. 21.1 Severe constriction of visual fields from chronic untreated papilledema, resulting in legal blindness. The patient’s visual acuity is 20/30 in both eyes, but there is less than 10 degrees of residual central vision, resulting in severe visual impairment. Although the patient can read individual small letters and identify objects and people, reading sentences is very difficult, and ambulation without assistance is impossible. The patient is not legally allowed to drive.

Some people who fall into this category can use their residual to complete daily tasks without relying on alternative methods. The role of a low vision specialist is to maximize the functional level of a patient’s vision by optical or nonoptical means.

21.1 Defining Visual Disability

The World Health Organization lists several categories of visual disability:

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  Low vision is defined as follows:

  
  
  
  
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    Best corrected (with glasses) visual acuity between 20/60 and 20/200

    
    
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    Or corresponding visual field loss to < 20 degrees in the better eye

  
  
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  Blindness is defined as follows:

  
  
  
  
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    Best corrected visual acuity of less than 20/400

    
    
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    Or corresponding visual field loss to < 10 degrees in the better eye

The Social Security Administration of the United States declares a taxpayer disabled for economic purposes and eligible for supplemental security income when

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  the best corrected visual acuity is 20/200 or worse in the better eye, or

  
  
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  the visual field is limited to 20 degrees or less in the better eye, or both.

21.2 Treatment of the Visually Impaired Patient

Aside from medical treatment of the cause of visual loss, information, rehabilitation, education, and work and social integration are essential for visually impaired patients. Such patients should be referred to specialized clinics dedicated to the management of visually impaired patients, such as low vision clinics or centers for the visually impaired.

Information is fundamental and must be offered by physicians, once a diagnosis of irreversible visual loss is made:

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  Administrative aids are very important and range from help with applying for disability to where to find various resources,

  
  
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  Adaptation to the disability and psychological help are priority issues and must be confronted from the start.

  
  
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  Education of the patient and his or her family to confront the new situation is also essential and must be addressed early.

  
  
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  Adaptation of the home is essential in maintaining autonomy and ensuring safety.

  
  
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  Adaptation of the workplace is regulated by laws and must be considered before applying for disability.

  
  
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  Information for the school is essential for visually impaired children and college students who can benefit from specific aids.

  
  
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  Social integration aids facilitate adapted leisure and cultural activities. Information on such aids is most often obtained from low vision clinics or centers for the visually impaired, and from private foundations.

21.2.1 Optical Aids

The vast majority of patients with low vision can be helped to function at a higher level with the use of low vision devices. Low vision specialists recommend appropriate low vision devices (the general goal of which is to magnify the image) and counsel patients on how to better deal with their reduced vision in general. Many government and private organizations exist to aid the visually impaired.

Various aids and tools can improve distance vision, near vision, and sensitivity to contrast; others facilitate activities of daily life (alarms, talking watches, special phones, books in Braille, audiobooks, text-to-speech computer programs, etc.).

Computers are important tools of integration for the visually impaired person. They allow, using standard or specific programs, screen magnification and conversion of text into sound or touch (Braille line) and are useful for all levels of visual handicap. Scanners can, in conjunction with text-to-speech software, read the contents of books and documents aloud via computer. Vendors also build closed-circuit televisions that electronically magnify paper, and even change its contrast and color, for visually impaired users. The recent development of tablets and smartphones has revolutionized low vision aids; numerous applications allow magnification of objects or text (▶ Fig. 21.2), scanning of bar codes, dictation of messages or emails, and improved navigation with a Global Positioning System, among others.

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