International health insurance customers might want to book themselves in for an eye test if they are struggling to concentrate at work.
According to Daska Barnett, an optometrist, office workers could find themselves tired and uncomfortable if they look at a computer screen all day.
To avoid this, Ms Barnett urged people to have their eyes examined on a regular basis.
International health insurance customers could well find that they are covered for this under their policies.
They should find that they are "more productive and just much more comfortable" if their eyes are in good health.
The advice follows the latest Sickness Absence Survey from the EEF and Westfield Health.
According to the survey, there has been a steady decline in sickness absence in Europe between 2007 and 2010.
Previously, the average employee took 6.7 days sick leave a year; but this had dropped to just five days by 2010.