Shame on your neurologist. This would be called a 'transient obscuration of vision" the causes include a variety of neurological, cardio-vascular and eye problems. You have to start out with seeing an Eye MD ophthalmologist for a complete exam which should include a "macular OCT test and peripheral vision test" You should also report it to your family MD or internist. The "most likely" cause depends on your age and general health and the type of seizure you have. The more risk factors you have older age, hypertension, diabetes, nicotine/pot use, obesity, elevated cholesterol, family history of cardiovascular/neurological disease the most likely this could be something very serious. So start with seeing ophthalmologist, ask for those special tests, report to you primary care doctor, and I would suggest you ask your neurologist not to so lightly dismiss this and work with you to be sure this is not a "TIA) transient ischemic attack.