Well I have done a little bit of finding out about all the eye 'stuff' so here it is. Basically, in the short-term the thickening of the vitreous humour results in extra floaters (black blobs in my vision), which in themselves are benign, if annoying. However, there is the possibility that this thickening can lead to the vitrous humour pulling on the retina and detaching it, which will be why the optometrist asked if I'd seen a sudden shower of black floaters and flashing lights as this is a symptom of detaching retina. Apparantly it's not common for this to happen, but is a possibility that could occur at any time in the future. I'm going to hope that I don't turn out to be unusual in yet another area of medicine, especially as I already have one fairly rare eye condition - Adies Pupil. I won't go into the complexities of that at the moment though.
That's it for now folks, but I'll be back shortly.