"I had some eyeglasses. I was walking down the street when suddenly the prescription ran out"

This quote by Steven Wright is a humorous take on the concept of having a limited quantity of time to do something. It indicates that the glasses he had were only momentary and that he was not able to utilize them for long. The expression "the prescription ran out" can be interpreted as a metaphor for the limited amount of time he had to use the glasses. It might also be taken an advising to be mindful of the time we have to do something, as it can run out promptly. The quote is a tip to make the most of our time and also to not take it for provided. It is also a tip to be prepared for the unanticipated, as the spectacles running out of prescription was an unexpected event.