How bad was John Lennon's eyesight?

John Lennon's 'stage stare.'

John Lennon was very short-sighted, but in his teens refused to wear spectacles in public.

This gave his ‘resting’ face an intimidating intensity - something that Paul McCartney noticed even before they met (‘a ted with a hard stare’). It also led to a comical Christmas incident, which Paul recounts here:

On stage, ‘the Lennon stare’ became a feature, but in his mid twenties, Lennon came out about his myopia. The catalyst was a pair of spectacles required for his part in the film How I Won the War (1967). 

NHS Specs

These were what the British used to call ‘NHS specs’ (state-subsidised wire-framed ones with round lenses).

John Lennon in How I Won the War

'NHS specs' now became part of Lennon's earnest new image: as a socially concerned college student. In fact, ‘John Lennon glasses’ became a popular fashion feature for aspiring intellectuals.

One thing that the teenage John Lennon could never have anticipated was that his hated eyewear would end up as prize exhibit in a museum.

Why did John Lennon stop driving? A calamitous motoring tour of the Scottish Highlands.