Disability Weights for Visual Impairment and Blindness Jill Keeffe Centre for Eye Research Australia (CERA)

Terminology Disability weights – 0 to 1 ratio scale YLL and YLD Disease Health states Activities Participation Well-being, quality of life

GBD Methods for DW 1990 GBD disability classes for ADL – Eating and personal hygiene – ADL such as meal planning – procreation – Occupation – Education – Recreation Panel of experts assigned weights deriving average weights

1996 Revision Person trade-off method DALY Suitable for adults but not replicable Not sensitive to mild levels of health states

GBD Based on 1990 weights Panel of experts Proportion of time in a class If weights not available results for Dutch or Australian studies used Dutch study added health state distributions for sequelae from EQ-5D Vision 4.2% of GBD; in top 7 diseases

New GBD Diseases Health states in 0 to 1 scale Not utility, contribution to health and welfare, activities or participation Departure from ideal health on ratio scale so makes comparison possible Homogenous health experience

Disease Dysfunctions of the body system Discrete list under groups Sense organs: glaucoma, cataracts, AMD, RE CVD and Circulatory: Ophtalmia neonatorum, corneal scar in LBW children Nutritional: VAD NTD: onchocerciasis, trachoma Diabetes: retinopathy

Health States Core domains of body functions Ambulation, cognition Senses such as vision and hearing Functional health domains, not well-being GBD uses disability as a proxy for loss of health in the terminology YLD and DALY “what can be seen”, ie vision loss, not performance

Disability Weight Loss of health measured in decrements of health capacity Quantification of the level severity of health of each domain – low vision or blindness Average health state valuation across the entire distribution experienced by all individuals Same across countries

YLD For each case or sequela YLD = incidence, average duration until remission or death and average disability weight Community survey of chronic health states Checklist and cognitive interviews Rating of health states Surveys in 3 countries Health professionals ranking and VA scale 0-1

Implications Impact of vision on physical function can be quite limited Corrected vision not loss of function Use in cost effectiveness analysis

Global blindness by etiology Source: GBD 2010 Estimation Strategy Report for Vision Loss

Global Low Vision Loss by etiology Source: GBD 2010 Estimation Strategy Report for Vision Loss

Global prediction of blindness for females by etiology and age Source: GBD 2010 Estimation Strategy Report for Vision Loss

Global prediction from low vision for females by etiology and age Source: GBD 2010 Estimation Strategy Report for Vision Loss

Predicted number from blindness in North America males by etiology and age Source: GBD 2010 Estimation Strategy Report for Vision Loss

Blindness 1990 Source: GBD 2010 Estimation Strategy Report for Vision Loss

Blindness 2010 Source: GBD 2010 Estimation Strategy Report for Vision Loss

Near vision loss 2005 Source: GBD 2010 Estimation Strategy Report for Vision Loss

Low vision 2005 Source: GBD 2010 Estimation Strategy Report for Vision Loss

Blindness 2005 Source: GBD 2010 Estimation Strategy Report for Vision Loss