Vision loss in Australia

To the Editor: Taylor and colleagues have provided an excellent analysis of the prevalence and causes of vision loss in Australia.1 However, their conclusion that vision loss in Australia is a much bigger problem than is usually recognised and requires “save your sight” public promotion bears some discussion.

The main outcome measure used was impairment in visual acuity. Impairment does not necessarily equate with disability. Disability has been defined as an alteration of an individual’s capacity to meet personal, social or occupational demands, or statutary or regulatory requirements, because of an impairment.2 An impaired person is not necessarily disabled.

The study of Taylor et al did not use measures of visual disability, such as the VF-14 (Visual Function Index). Participants were asked to complete a questionnaire that included information about “symptoms of eye disease”, but it is not clear that the questionnaire explored self-perceived problems with vision. Nor does the study seem to have looked at the level of cognitive impairment within this aged population. Tielsch et al, in a similar study,3 made the point that whether people who have both a treatable loss of vision and cognitive impairment should receive ophthalmological intervention depends on the cause and severity of the cognitive deficit.

Further, Taylor and colleagues stated that, after undercorrected refractive error, cataract is the most common cause of low vision and is also comparatively easily treated, but they did not objectively evaluate the relative risks and benefits of such interventions.

The study provides interesting data on the extent of visual impairment in Australia, but the authors are presupposing that the uncovered prevalence of visual impairment necessarily constitutes a social problem requiring “save your sight” public health measures. Reference should be made to patient goals and needs, and an objective cost–benefit analysis, before such a conclusion can be reached.