A worker had a job sorting apples at a produce distributor. The apples would travel along a conveyor belt, and the sorters would divide them into different grades. The work required sharp eyesight and manual dexterity.

The distributor required sorters to process a certain volume of apples each day to specific standards of accuracy. After several years on the job, the worker’s accuracy and productivity consistently dropped below the required levels. At the time, the worker was 60 years old. The...