I help others understand by explaining a few symptoms in terms that they understand. For example:

When I come to a stop sign and look to the left, I notice if there are any cars coming. When I look to the right to see if there are any cars coming, I have already forgotten what I just saw to the left.

My work-around is to repeat to myself, "No cars from the left" as I look to the right. Now I have a single item in auditory/verbal memory and a single item in visual memory.

I also explain that I cannot visualize any more. That 'mind's eye' is not there any more.

I have other symptoms that get a bit more complex that I only explain to those who are interested.