My eye spasm problem started soon after I was diagnosed with Parkinson's early in 2013. My eyes were often blinking all the time and some times closed more than they were open. I found it very difficult to hold them open at the peak of a spasm and like you it was not safe to cross a busy road or drive. They were worse in the evenings, watching TV or a PC screen was impossible as it would set them of again. I have not had DBS, just the normal Parkinson's drugs. I have not found any tricks that would hold them open. Often the Botox injections would have side effects of their own. Mainly double vision but this would only last a week or so, thereafter my eyes would be good again for a couple of months and if I am lucky I am able to drive again, just short distances around the village.