Vision impairment in Aboriginal and Torres Strait Islander peoples: a toolkit to assess prevalence and impact

Abstract

The eye health of Aboriginal and Torres Strait Islander peoples, like many other health outcomes, is far worse than that of non-Indigenous Australians. Accordingly, there is a great need for current epidemiological data on the prevalence, causes and impact of vision impairment. This thesis describes the development and validity testing of a ‘Toolkit’ to assist in addressing this need. The Toolkit consists of two components: a) the Rapid Assessment of Blindness and Vision Impairment in Indigenous Communities Protocol (RABVIIC), a methodology designed to detect the common causes of vision loss and tested to ensure validity and cultural acceptability; and b) the Impact of Vision Impairment: Indigenous Peoples Questionnaire (IVI_I), a vision-related quality of life instrument modified for cultural appropriateness and evaluated for psychometric acceptability. Out of 135 eligible participants, 129 (95.5%) were examined with the RABVIIC and 128 (94.8%) were examined by optometrists. The assigning of cause of vision impairment was very similar for both methods. Vision impairment from non-refractive causes was detected with 75% sensitivity and 98% specificity by the RABVIIC. Vision impairment from refractive error was detected with 72% sensitivity and 99% specificity. The IVI_I demonstrated internal consistency (Cronbach’s α=0.96), cultural appropriateness and discriminated between participants with normal vision from those with vision impairment (U=1231.0, p<.001). Mild vision impairment (<6/12 to 6/18 in the better eye) was associated with difficulty or concern with many activities of daily life. The RABVIIC is a valid, rapid methodology able to detect vision impairment due to refractive error, diabetic retinopathy, cataract, glaucoma, and trachoma in Aboriginal and Torres Strait Islander populations and was the methodology used by the National Indigenous Eye Health Survey. The IVI_I has shown that significant improvements in vision-related quality of life may be achievable through correction of refractive errors, cataract surgery or low vision rehabilitation. Also, the IVI_I tool will be useful for clinical practice to evaluate outcomes of intervention programs or rehabilitation. The (ICEE) Toolkit presented in this thesis will help to design and monitor intervention strategies that will help alleviate the excess blindness and vision impairment in Aboriginal and Torres Strait Islander peoples.