Update of a Simple Model to Calculate the Annual Global Productivity Loss Due to Blindness and Moderate and Severe Vision Impairment

Abstract

Purpose: To develop a simple but more precise model to calculate potential annual productivity losses due to blindness and moderate and severe vision impairment (MSVI) at the national, regional, and global level.

Methods: Productivity loss was defined as the loss of minimum wage/Gross National Income per capita (GNI) incurred by people aged 50-64 years with blindness or MSVI, who were not able to work or worked with reduced earnings in 2020. We developed a global list of minimum wage data from on-line sources. All other model data were sourced from international, standardised, and open-access databases. For blindness, the total productivity loss (not working) incurred by 64%-90% of the affected population was summed up with partial productivity loss, defined as 10%-36% of the affected population earning one-third of that of the sighted population. For MSVI, the total productivity loss for 30%-55% of the affected population was summed with the partial productivity loss, defined as 45%-70% of the affected population having 35% reduced earnings. The costs of blindness and MSVI were summed to obtain the cost of combined vision loss.

Results: The global cost of vision loss based on minimum wage was US$160-US$216.32 billion for 2020. The global cost of vision loss using GNI was US$449.36-US$584.66 billion.

Conclusions: A parsimonious model that considers minimum wage and GNI potentially lost due to blindness and MSVI can be used for eye care programming planning and advocacy at the national, regional, and global level.

Keywords: Productivity loss; blindness; costs; gross national income per capita; minimum wage; model; moderate and severe vision impairment.