Speer's Eye of Boob Detection is Albert Speer's ability to do the same thing any male did, do and will do at some point in his life: stare at boobs.
Since the "Eye" in the title is singular, it is unknown which eye (left or right) is being referred to, or whether there is any difference.
Its use can be observed in the Bormann informs Hitler scene when Speer arrives at the Führerbunker on 22 April and Traudl greets him. He lowers his head until reaching good angle to stare at her boobs. It had few appearances (although not explicitly mentioned) in MoarHitlerParodies The Pwnage of Albert Speer; and was used when Fegelein trapped Traudl and Gerda in a Günsche costume - neither the mask nor the SS uniform fooled him.
The scene later repeats, where the two has a dialogue on the staircase connecting Führerbunker and the Vörbunker. The elevation difference makes the Eye more effective.
The Boob Dome
Speer's boob detection is later augmented by his boob detector, affectionately called the Boob-shaped Dome, which arguably possess superior boob detecting abilities, and one that others, such as Hitler, can also use.