"His hair will likely get darker, though not as dark as yours." Something about the pigment in his retina, though whatever it is is somehow balanced by how dark his irises are. Honest.
I'm impressed that he was able to assess so much of Aidan's perfection from the little examination and no feedback he was able to get from a 20-month old boy. He didn't inherit my far-sightedness; he has a slight astigmatism, though that's common for his age, and he'll grow out of it. Here was a surprise - "good" vision for a little guy Aidan's age is 20/60, not 20/20. That's why toddlers are always getting so close to things - it's the only way they can see them clearly. Who knew?