The economic burden of global blindness: a price too high!

The World Health Organisation defines blindness as a best corrected visual acuity of less than 3/60.1 Using this definition it is estimated that there are currently 37 9 million blind people (1-4 million children 0-15 years of age, and 36-5 million adults 15 years of age or greater) worldwide.2 Of this figure roughly 75% of all blind people live in the developing countries of Asia (21-4 million) and Africa (7.1 million), typically in rural areas with few or drastically underused eye care facilities.2 3 At least 50% to 70% of all cases of childhood blindness and 75% of adult blindness are either preventable or curable with currently available medical or surgical technology.3 Moreover, blindness prevention and treatment strategies are among the most cost effective of all known medical interventions.4 In economic terms, the cost of blindness depends not only on the cause and duration of the blinding disease, but also on the availability of family or alternative sources of economic assistance for blind individuals. Not surprisingly, therefore, children blinded during childhood or at birth incur a higher economic cost to their family members and society over their lifetime than adults blinded in later life. By the same token, the cost of blindness also depends upon how many blind people are economically productive, as well as on how many would enter economic activity if they were able to do so. While these variables are difficult to fully quantify on a global scale, a proxy measure of the cost of blindness may be had by estimating the loss of per capita gross national product (GNP) as a result of the loss of income from blind people over an individual's working life in each of the main global economic divisions. The guiding assumption of this approach is that blind people do not contribute to GNP when they are blind. While this is obviously not the case, exactly what proportion of per capita GNP may be attributed to blind people has not yet been reliability determined. Table 1 summarises the population size, average GNP per capita, prevalence of blindness, number of blind, total working years lost due to blindness, and the loss of per capita and total GNP due to blindness for each of the main economic divisions. In calculating the per capita GNP lost due to blindness it is assumed that GNP would otherwise have grown by a rate of 3% per annum and that there were no new cases of blindness that is, a best case scenario! It is further assumed that the total number of working years lost as a result of adult blindness ranges from 0-10 years, while for childhood blindness the figure ranges from 0-50 years. Lastly, it is assumed that 75°/O of adult blindness and 50°/O of childhood blindness is either curable or preventable. The most striking feature of Table 1 is that the total GNP lost as a result ofboth childhood and adult blindness combined ranges from a low of US$ 167 518 million to a high of US$ 243 938 million. The total GNP of the UK, by contrast, is roughly US$ 1 045 674 million.5 Viewed in other terms the total cost of global blindness is equal to roughly a sixth to a quarter ofUK GNP. Clearly, the costs of blindness are unacceptably high, not only for blind people, but for society as a whole. What can be done to reduce these costs? No single, or simple, solution exists. However, it is possible to organise the financial and personnel resources, both public and private, which are now available to combat blindness in far more effective ways. Sophisticated tools being developed in the emerging fields of 'ophthalmic services research' provide significant guidance in this context. 'Broadly defined, ophthalmic services research is