Hi there!
Well, without a clinical evaluation it would be difficult to determine the cause of your symptoms. Without any other symptoms associated, this is unlikely to be a case of opthalmic migraine. Possibilities that may need to be considered include amaurosis fugax, ischaemia, TIA, vascular issues, increased intra ocular pressure etc. Since this has been a single incident and it has been sometime since the episode, there is the possibility of all tests being clear. Nevertheless you may consider an evaluation y an ophthalmologist and a neurologist for a detailed evaluation and suggestion of an appropriate management plan, if required.
Hope this is helpful
Take care!
Just to add, I was 17 years old when the vision disturbance occurred. It has never occurred since.