According to several stories from crews serving with Bomber Command, due to the shortage of food supplies during the war, the crews used to eat sandwiches made with Bilberry jam whilst on flights. After a month or two they reported a marked improvement in their night vision and their ability to spot incoming enemy aircraft at greater distances.
This had been backed up by testimonies from several people I know recently who have stated it has reduced eyestrain from sitting in front of a computer screen for long periods of time.
Could be a way to help spot those pesky 109s. Bilberry tea anyone?
