There is no dilemma. Darwin was not
dismantling his own theory of Evolution. If those people, who lean back and smirk, as they think they found a weak spot, would care to read the rest of that paragraph, they would see, that Darwin gave the answer himself. But as usual this line of Darwin is taken out of context and as usual those, who use this quote, "forget" to show us the rest of Darwins statement, that follows right after the quoted part.
But let´s read, what Darwin has to say about it:
"Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real."
And we don´t even have to look for "partially eyed" fossils for that. Even if we just look at living species, we can see, who the eyes evolved from simple photoreceptor cells to the mammalian eye. Not to forget, that there are a large number of species around, that show us less developed, more simple eyes, which fill the gaps (for example the pinhole eye of the nautilus). Not to mention that if we look at the "best" eyes today we can see all the evolutionary baggage, which would not be there, if there was a designer.