Hi,
I have had a similar problem with my (11-13? Y/O) Basenji female, Zeenie. She isn't blind but I know her vision isn't good. I know her blood sugar was somewhat abnormal at her last blood test, but like your dog, it was right after a seizure and I understand that is to be expected. Her first seizure was this past August and she has been to the vet several times for testing, etc. since. There is no conclusive diagnosis but 1/2 the dose of a 32.4 mcg pill of Phenobarbital twice daily (given religiously at 12 hour intervals) seems to eliminate the seizures altogether (knock on wood.)
I don't know what our next step is. I know I don't want any thing invasive, but I also can't afford an MRI: maybe an EEG or CT scan? If there is anyone else out there with advice, that would be welcome.
Anyway, if you need support or just want to vent or brainstorm together, please let me know. I am in NC in the US (EST.) and maybe we can exchange phone info later.
Best of luck to you. I know how you feel.
Lauma