I was in a similar situation as you last year. I was diagnosed to be borderline glaucoma. My eye pressure was basically too high which in time could lead to damage to the optical nerve and eventually loss of peripheral vision. This has not happened so my field tests are just fine.
I talked to the CAA about this and they said to me that if I can pass the field test (which I did), then they don't have any problem with me taking daily eye drops to keep the pressure under control. I just need to send them my field test results every year now.
Your situation is different as you say your left eye has only 60% view. That may be a problem. I would advise you to talk to the CAA directly. They are understanding and there is no point "hiding" information from them.
You will need to have an Estermann field test done. That's a particular field test they prefer which very few high street opticians actually do.
So I'd say talk to the CAA eye department. They will probably tell you to get one of those Estermann tests done. Or you could go to Gatwick for your class 1 medical of course, but you 'd better make sure the 60% vision is not an issue for them (it could well be, I'm afraid), otherwise the fee for the class 1 is a waste of money...
Good luck with it. Don't give up, I got my class 1 Medical in the end.
