Presumably the eyesight decision was the result of a medical examination? If so, you might find other ATC providers in Europe would refuse you for the same reason.
If it was not the result of a medical, you need to have one before making any decisions. The only alternative to you close to home would be one of the private companies which charge an arm and a leg to train controllers. If you did that and then failed the medical.........
You say that you are older than 25 - by how much? Training from scratch in ATC becomes more difficult the older one gets, although some do achieve success.