First of all I reassure you it does not sound like you are having MS, or any other serious health issues. Your symptoms indeed sound like ocular migraine. Especially now with your mri of the brain too being normal we are certainly not dealing with MS or any structural problems in the brain like tumors or stroke etc.
Migraine can start any time in life, especially around your age. Not always there are any obvious trigger factors. But careful search for any trigger factor may reveal some trigger factor and avoiding such trigger may help in reducing or eliminating migraine attacks in the future.
The following are various examples of migraine triggers;
Varieties of food stuff (mentioned in details again below), food-preservatives (MSG, nitrates etc), caffeine, chemicals such as perfumes, cleaning agents, cigarette smoke, medication side effects, stress, depression, sleep deprivation, food deprivation (hypoglycemia or low blood sugar), weather changes, bright lights, video games, certain odors, hormonal, alcohol especially red wine etc; and for different people the triggers may be different.
These below are examples of the food triggers for migraine;
Avocados, Bananas, Beef liver, Blue cheese, Bologna, Canned soup, Camembert cheese, Cheddar cheese, Chic***** *****ver, Dates, Dried figs, Fava beans, Garbanzo beans, Kiwi, Lima beans, Nuts, Olives, Onions, Papaya, Peanut butter, Pepperoni, Pineapple, Pinto beans, Raisins, Raspberries, Red plums, Roquefort cheese, Salami, Sauerkraut, Soy sauce, Spinach, Stilton cheese, Summer sausage, Swiss cheese, Teriyaki, Tofu, Tomatoes, Yeast, Yeast extracts, ice cream, chocolate etc.
If you identify any of the above as a migraine trigger in your case try to avoid it as much as possible and as pointed above avoiding the triggers itself can significantly help in controlling the migraine attack and reduce the need for any migraine medications.
There are some indications that gluten intolerance (either associated with celiac disease or without celiac disease) and inflammatory bowel diseases etc too can increase the risk of migraine so you may talk to your clinic doctors and ask them to look for these diseases and if these diseases are present then they are treated appropriately.
If these attacks are occurring frequently then there are treatments also available. For the acute attacks and also for prevention of future attacks there are various medication treatments and non-medication treatment options available and if these attacks are happening again and again then you may consider starting such treatments.
Please let me know if you have any further questions; and if you feel you have received the answer to your question please rate me so that I can receive credit for the time and effort put by me in answering your question.