Perspective
He peered at the glasses.
"The lenses show that the woman who wears these is nearsighted. They're an older style, but they show little sign of wear. She must forget to put them on most of the time.
"The crack on the right side indicates a fist to the temple. Unexpected, because her head must have turned toward the blow. The shattered left lens and bend in the frame indicate that an projectile was used. I would be surprised if the woman still lived."
"Wrong, John. Mycroft lives, but wants to kill me for throwing his glasses under a Routemaster."