That's a different answer to the one I've just found.
Apple pips contain minute traces of Cyanide (it says) and by scoffing enough the Cyanide damages the optic nerve.

Although you need to scoff immense quantities for this to happen.
( The Disappointed Caravanner of the year, Tue 16 Nov 2010, 21:36, 1 reply, 15 years ago)

I think the methanol explanation is more likely
I've heard about the cyanide in apple pips thing before and you would need vast vast quantities.
( Vipros. clever got me this far, then tricky got me in, Tue 16 Nov 2010, 21:38, Reply)

I think you're right
Concentrated Cyanide kills by destroying the central nervous system, but you'd need a hell of a lot of it via the medium of cider.

To go blind by scoffing cider you'd have to somehow bypass death by cirrhosis.

I feel liberated and able to try raw cider, uninhibited by assumed knowledge from my youth.
( The Disappointed Caravanner of the year, Tue 16 Nov 2010, 21:54, Reply)