I have been on Prozac for about 5 years and still occasionally get these "zaps". It's an awful sensation and I don't know why I continue to get them after being on the same amount consistently for this time. So if anyone else not weening and/or starting an SSRI gets them, you're not alone. I remember getting the shocks while weening off Effexor long ago, and this was explained to me as normal and brain chemistry-related, but they continue with the Prozac. They are temporary and intermittent.
Stretching the eyes works temporarily but I find I get these when I've been inactive for 2-3 days or more. Physical activity helps and gets rid of them for me, but it takes a day, sometimes two, of being physical active.
Thanks, Dr. Colett for the explanation.