As far as I can figure out from the various pieces of information on the web, ATCOs need a Class 1 medical. The details of the eyesight requirements for this are given here:
http://www.caa.co.uk/docs/49/SRG_MED...isual_Stds.pdf
The initial standard you must attain is 5 dioptres either of short- or long-sightedness (plus other bits to do with astigmatisms etc). For renewal of the Class 1 medical certificate (see the link from the link above!) these get less stringent - for short sight at least - so you've got some leeway for your eyes to get worse over the years!
I'd also like to know whether the answers to the personal questions on the application form (why do you want to do this job, give details of your responsibilities, etc) have any bearing on whether you get invited to the initial (pencil and paper) tests, or not? Either way I assume they'll refer to these if you get through to the interview stage, but has anyone been told that they weren't invited to the initial tests on the basis of their application form?
Cheers all,
Jen