Introduction to Assistive Technology for Vision Impairments

Module 1.5. Conclusion

For persons with vision impairment, a comprehensive eye examination should be followed by a functional vision evaluation, to check how the person uses his or her vision to function. Quantitative measures like visual acuity and visual field cannot alone indicate how much a person’s life will be affected by vision loss as it is also important to assess how well a person uses the vision they have. Two people with the same visual acuity level may differ in their ability to use his or her vision better to do everyday tasks.
A person’s functional vision can be evaluated by observing them in different settings to see how they use their vision. The results of a functional vision evaluation will allow an individual’s care team of rehabilitative therapists and special educators to better understand his or her challenges in completing everyday tasks, designing and implementing strategies to improve the functional abilities. In the following module, we will learn more about the challenges faced by persons with vision impairment.

Key Takeaways
  1. The limitation of the visual system’s actions and functions is referred to as visual impairment.
  2. Visual efficiency is measured in terms of visual acuity (the ability of the eye to see objects at a given distance. It is otherwise called sharpness or clarity of vision) and visual field (The total area (field of vision) that is visible when the eyes are fixed on a single object. This helps to understand the blind spots).
  3. There are different types of vision impairment. It varies from person to person. Although it would be simple to think that blindness is simply the lack of vision. Some lose their sight later in life, while others are blind from birth. Blindness may occur suddenly or very gradually.
  4. The condition in which the eye of the person is healthy but the area of the brain that receives the signal from the photoreceptors gets damaged or is underdeveloped is called Cerebral Visual Impairment (CVI).