I hear you and I'm not trying to play the definition game or wriggle out of this. The way I conceptualized the question -- which I think the original poster had in mind and what I think is relevant to hazard risk assessment -- is more like one of these:
A) "What fraction of the public is seriously vulnerable to sensory hazards",
B) "Given that one knows one's medical history and demographics, what is the probability that there are sensory hazards one is vulnerable to but not already well aware of."
My hunch is that the answers are "less than 20%" and "close to zero." The example of epilepsy didn't shift my beliefs about either; epilepsy is rare and is rarely adult-onset for the non-elderly.
B) "Given that one knows one's medical history and demographics, what is the probability that there are sensory hazards one is vulnerable to but not already well aware of."
So you're asking, what new medical sensory hazards may be developed in the future.
Well, the example of photosensitive epilepsy, where no trigger is mentioned which could have existed before the 19th century or so, suggests you should be very wary of thinking the risk of new sensory hazards is close to zero. Flash grenades are another visual example of a historically novel se...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Of course, for "every Monday", the last one should have been dated July 22-28. *cough*