Friedrich's Optik is one of the nicest eyeglass shops in NYC. It's a German company that has been around since the early 1800's, and has very few brick-and-mortar shops in the US.
Located on Park Avenue, the unassuming shop mostly stocks women's eyeglasses, but does also have a few pairs of men's eyeglasses. The standout eyeglasses are made from buffalo horn. While the price is steep (upwards of $1500), they are beautifully crafted and more unique than what you would get at Oliver Peoples or Warby Parker.
Check out their instagram here.