My boss keeps waving his hand in front of my face

Hi,

I wear noise-cancelling headphones at work, and together with my tendency hyper-focus, sometimes I can become totally zoned out of my external environment. Sometimes, when my supervisor has something to say to me, he visits my desk without any warning and waves his hand in front of my face - otherwise there is no chance I would notice him there.

The thing is, like most autistic people, being suddenly distracted or surprised makes me stressed. Often my heart starts racing, my face goes red and I can't process what the person is saying, or figure out how to respond. My supervisor knows I am autistic but I'm not sure he understands some of the lesser-known issues (e.g. difficulties being interrupted and task-switching). 

I'm not sure I want to give my boss a list of instructions for how to interact with me. I was considering asking the university disability service to circulate some practical guidelines on how to be around autistic student/staff. I'm already in a noisy, open-plan environment with essentially no adjustments, so I do feel like I should do something. 

Has anyone else experienced this? 

Cheers!