Nick Bates (Cy Chadwick) in The Woolpack in 1989 with Seth Armstrong (Stan Richards) and Jock MacDonald (Drew Dawson), and at an interview for the job of gardener at Home Farm - also in 1989.
Further to Chris' enquiry about Nick Bates (Cy Chadwick) wearing glasses in 1990 episodes of Emmerdale, I have checked all the episodes, beginning in March 1990 (when Nick was already wearing glasses) and working backwards.
The first appearance of the character wearing glasses dates back to 1989 - episode 1412, broadcast on 14 December.
I have skimmed through the episodes, looking at all scenes involving Nick and also his sister, Kathy Merrick (Malandra Burrows), and have found no reference in the dialogue to Nick's glasses at all.
It seems likely that actor Cy Chadwick was wearing glasses at the time, and that's why Nick suddenly wore them as well.
Actually, it's been good to focus on Nick for a while. The character was very ordinary and believable, but Cy Chadwick's portrayal never seemed dull.