We’ve long been told that eating carrots is the key to good eyesight.

But it turns out, leafy green vegetables may be the secret to boosting our sight.

A diet rich in nitrate – found in spinach, kale and lettuce – reduces the risk of glaucoma by up to 30 per cent, scientists revealed.

Nearly three million people in the US currently suffer from glaucoma – a disease of the eye’s optic nerve.