Simply put, yes and no. Carrots contain Vitamin A, otherwise known as Retinol (and those etymologists of you will already be drawing the link between “retinol” and “retina” here).
What is Retinol?
Retinol is what your body requires in order to synthesize Rhodopsin.
This is the pigment in your eyes which operates in low-light situations and thus allows you to see better in the dark.
If you had a Vitamin A or Retinol deficiency, then eating a shedload of carrots would be a great way to straighten this out, but only to the point of a normal healthy person.
Likewise, eating carrots for a normal healthy person would only cause such an infinitesimal gain in night vision.
It wouldn’t be worth eating carrots like your Bugs Bunny.
Where exactly did this “fact” come from?
Is it a rumor made to get kids to eat their veg? Or is it a piece of heartfelt public health information?
Well, no. Like many other rumors it was government propaganda. Well, a step up from that actually, it was wartime government propaganda.
During the early stages of World War II, The Battle of Britain was taking place over the United Kingdom and the Luftwaffe was bombing the living hell out of British cities.
Each night with the cover of darkness came the hum of bomber engines as they crossed the channel, determined to bomb the British into submission.
However, a new(ish) invention known as Radar was helping the Brits detect the incoming Luftwaffe and scramble their RAF fighters in time for effective intercepts.
Not wanting the Germans to clock onto this, the Air Ministry made a load of press releases announcing their pilots were eating lots of carrots to help them have exceptional night vision.
It was so successful that not only did they fool the German High Command, but they also managed to fool the British people and that’s where the old wives tale comes from.