What is the central theme of poem "The Microscope" by Maxine Kumin?

This is an interesting poem which tells the story of Anton Leeuwenhoek, a scientific pioneer, in a misleadingly simplistic, almost childlike style which masks the profundity of its central idea. Leeuwenhoek, the poet says, sold "pincushions, cloth, and such," an occupation which he neglected in order to begin grinding lenses for a microscope. Possessed by the spirit of scientific inquiry, Leeuwenhoek spends his time examining everything he can think of under his lenses, everything from fish scales to his own blood to bugs so small they are hidden within a water drop. The irony here is that the scientist is making extensive and important scientific advancements, but the townsfolk aren't interested in this. They are only interested in why their store is not open, to provide them with their day-to-day necessities. Irritated by the scientist's deviation from the quotidian, they accuse him of being crazy, saying that he should be shipped off to Spain and calling him "dope." As the final line of the poem says, however, it is because of this man, striving for discovery in the face of public disapproval and mockery, that we "got the microscope."
The central idea of the poem, then, is that all science, when it is first developed, seems "crazy" to those who are interested only in what is immediately relevant to them. It is only the great innovators and geniuses—who can continue to work despite the disapproval of those around them—who actually advance our world.

"The Microscope" suggests that innovation requires genius, and that a genius is rarely understood by his contemporaries. It was necessary for Anton Leeuwenhoek to neglect the quotidian details of his life as a shopkeeper (his "dry goods gathered dust") to pursue his passion for devising a machine that would enable him to examine the unseen, minute details of the natural world. Innovators are not understood or appreciated until their efforts are proven to be of use; in fact, the speaker observes that Anton was called "dumpkof" by those unimaginative observers who were more interested in the practicalities of life: "pincushions, cloth, and such." These manufactured, prosaic items contrast with the exoticism of Nature's "mosquitoes’ wings" and "spiders’ spinning gear." The irony is that his work led him to be considered a pioneer of the very practical science of microbiology.