Sorry to hear about your news
@lely
You can slow down the progression and some people on the forum have said they've halted the progression altogether, but the best thing you can do is keep your bg,bp and cholesterol levels under control.
Whilst improving your diabetes control it's said to do this gradually as sudden tightening of bg contol can speed up the progression, if in doubt just speak with your Ophthalmologist or diabetes Consultant.
You may/may not of seen this website before, however it's worth posting agian as it has a wealth of info and advice on the diabetic retinopathy:
http://www.diabeticretinopathy.org.uk/back_diabetic_retinopathy.html