Table 1
Features of the visual function assessment and the functional vision assessment
| Assessment of visual function | Assessment of functional vision | |
|---|---|---|
| Examples | Visual acuity, visual field, contrast sensitivity, dark adaptation, colour vision | Use of vision to learn orientation and mobility, daily living skills, communication, sustained near activities, and to gain visual access to information |
| Measured | Separately for each eye | With both eyes open |
| Scale | Based on stimulus characteristics | Based on response characteristics |
| Tests | Single variable under controlled, usually static conditions | Multiple variables under real-life conditions |
| Criteria | Threshold performance | Sustainable performance |
| Involves | Visual parameters only | May also reflect non-visual factors |
Table 2
Profile of visual functioning
| Key vision areas | Example of vision-related functions |
|---|---|
| Ocular motor | Fixation, saccades, scanning, accommodation, refraction |
| Sensory functions | Visual acuity near and distance, contrast sensitivity, colour vision, visual field |
| Early processing | Figure ground, background ground, stereovision, matching colours |
| Interior temporal networks | Face recognition, reading words, copying pictures |
| Parietal networks | Spatial awareness, body awareness, eye-hand coordination |
1 Adapted from “What and How does this Child See?” (p. 153), by Hyvarinen and Jacob (2011), Finland: VISTEST. Reprinted with the author’s permission.
Figure 1
Fit for purpose approach to choice of visual or functional vision assessment. Adapted with permission from “Visual Impairment in Children due to Damage to the Brain” (p. 286), by G. N. Dutton and M. Bax, 2010, London: Mac Keith Press ISBN 9781898683865.
Figure 2
Model of Visual Functioning. From “Visual Function: A Theoretical Model for Individuals with low Vision,” by A. L. Corn (1983), Journal of Visual Impairment and Blindnesss 77, p. 374. Copyright © 1983 by American Foundation for the Blind. All rights reserved.
Figure 3
Model of Health and Health Deficits. From “Aspects of vision loss – visual functions and functional vision,” by A. Colenbrander (2003), Visual Impairment Research, 5, p. 116. Reprinted with permission http://www.tandfonline.com.
Figure 4
Revised Model of Health and Health Deficits. From “Assessment of functional vision and its rehabilitation,” by A. Colenbrander (2010), Acta Ophthalmologica, 88, p. 165. Reprinted with permission http://www.tandfonline.com.