As you probably know, in the USA a 1st class medical essentially doesn't required any specific uncorrected vision standard; as long as you can be corrected to 20/20, that's sufficient. Makes sense to me, since I've never flown without my glasses!
I looked into this issue about 3-4 years ago, at which time both ICAO and TC told me that they were "considering" adopting an approach similar to that of the USA. I don't know what progress has been made (things move very slowly at ICAO), but if your uncorrected vision is not up to snuff, it would be worth your while to make specific enquiries of TC's medical people rather than be deterred by what is on the Physical and Mental Requirements chart.