Behavioural adaptation - a clue to visual impairment?

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Vision impairment – when a person’s sight cannot be improved with glasses or contact lenses – should not be considered an unavoidable part of the natural ageing process.1 It is more than the loss of ability to read letters on a chart; it affects our ability to see in the dark and the speed at which we can read.

Often, vision impairment may not even be noticed by the person experiencing it, as they typically learn to cope with and adapt, especially when the other eye is not affected. It is essential, therefore, for us all to pay attention to any apparent behavioural changes in family members, friends and colleagues, which are potential indicators that their sight may be impaired.

One of the most common causes of vision impairment is the development of eye disease, which is especially common in the elderly. Diseases such as age­related macular degeneration (AMD), including geographic atrophy (GA) – an advanced form of AMD – and diabetic retinopathy all cause vision impairment if untreated.2

People with such diseases often experience difficulty in:

  • reading books, notices and labels
  • judging distance and recognising signs
  • driving, especially in low light environments
  • identifying colours
  • recognising faces of friends and relatives
  • performing tasks that require close vision, such as cooking or sewing1,2

Consequently, many people experiencing visual impairment may use coping strategies to help them adapt. These behavioural changes include (but are not limited to):

  • Squinting, tilting or turning their head when looking at objects
  • Holding reading materials, such as books, closer to their face
  • Moving hesitantly around household furniture and other obstacles3
  • Reducing active participation in social engagements and leaving the home environment

Ultimately, one of the most devastating consequences of visual impairment and disease progression is loss of independence. As visual impairment progresses, family members may find that it is no longer possible for their loved one to safely cook, clean, or navigate the home alone without undue risk of fall or injury. There are also a number of well­documented psychological issues surrounding vision impairment. It is not uncommon for people with such impairment to feel anxiety – either in relation to their vision impairment or anticipation of its future progression – as well as frustration, annoyance and embarrassment at not being able to complete daily tasks. 4,5 In part as a result of this loss of independence and increasing social isolation, around a third of people with AMD have clinical depression. 6

Being aware of behavioural changes relating to vision impairment – not only in ourselves but also in others – is important, as they are not always immediately recognisable. Fundamentally, behavioural changes should act as triggers to seek medical advice. Annual eye exams are recommended for everyone over age 60.7 Early intervention with appropriate treatment and support will lead to preservation of vision and a happier, healthier life.

References
1. NHS Choices Living with low vision. Accessed October 2015
2. National Eye Institute Information for Healthy Vision. Accessed October 2015
3. Lions Center for the Visually Impaired. Coping with Visual Impairment. Accessed October 2015
4. Fox S Visual Impairment: Understanding the Psychosocial Impact. MedScape. Accessed October 2015
5. Hassell JB et al. Br J Ophthalmol 2006;90:593–6
6. Brody BL et al. Ophthalmology 2001;108:1893–901
7. American Optometric Association. Adult vision: over 60 years of age. Accessed November 2015

Tags: Ophthalmology, AMD