Fab thread cheekyginger, thank you!
I have another hopeful story to add if that helps? My DD had an intermittent squint at 6mths old-I mentioned to GP and we got
referred to Moorfields eye hospital there and then as my mum and sister both have/had amblyopia (is that the same as lazy eye?).
She was 9mths old when we went to the first appt. We saw a collection of amazing people (Orthoptist, optometrist and ophthalmologist) and after about 4hrs of tests she was diagnosed with severe longsight (+4.5 and +5) and an astigmatism. The tests were as cheeky said, but my dd was given eye drops to dilate her pupils. The Optometrist then shone a light into each eye to work out where the light 'hit' (before or after the retina) and then held various lenses up between DD's eye and the light to work out the degree to which she was longsighted.
DD had her glasses within a week and I had been really worried about her pulling them off, but its never been an issue. From the minute we put them on her, she beamed!
She started focussing on us more when we were holding her (previously I guess too much work for her eyes to accommodate) and showed much more interest in stuff at close range.
DD is now 2.4 and so used to them. The prognosis is that she'll have to use glasses (or later, contacts) for the rest of her life, unless/ until a surgical technique is developed to sort out her condition. But we're not worried and i don't think she will be either. They're so much a part of her and who she is that we can't really imagine her NOT wearing them. Today for the first time she proudly talked about a character on TV "wearing glasses, just like me, Mummy!" which was great. 
Hope that helps-all the best to everyone out there just starting out with glasses/patching. It is worth it, I think. My sister's was caught much later so despite some patching and glasses through her her teens she now has one v longsighted eye and one slightly short-sighted eye. She only uses one contact lens though (no point with the v bad eye apparently) so monthlies last twice as long 