Also be aware that JAA has 'slightly' different rules for eyesight.
I am by birth one of those who needs glasses with a high rating (-7.00), but are still fully correctable with glasses. This has allowed me to fly commercially in Canada. Under JAA not only does it have to be correctable, but they have an upper limit of the eye. I think -6.00.
Just for everyone's info.
This is only on the initial test. For renewal there is no limit. I have read in a document from the UK CAA that they are trying to remove the refraction limit. I have -7.00 aswell so I can only agree with them, as I still have to get a good reason for having the limits. There is only a problem when wearing glasses, but there is no problem with contact lenses.
If you already have a Canadian Class 1 medical and they change to JAR, then you will be able to convert your class 1 as a renewal, as far as what I have heard.