Visual ergonomics interventions in mail sorting facilities.

This study was performed between 2004 and 2011 at mail sorting facilities in Sweden. During this time, different interventions were performed. The first was a lighting intervention that had a positive impact on the postal workers, especially those with eyestrain. A new lighting system also improved the illuminance and gave better light distribution. The second intervention involved new personal spectacles for the postal workers who needed them and this had a positive effect on eyestrain. The third intervention involved a specific type of sorting spectacles for the postal workers who already used progressive lenses privately. The reading distances that the postal workers had while sorting the mail was inverted to the distances in their regular progressive lenses. The new sorting spectacles had a positive effect on head postures and on muscular activity.