A surgical device (10) includes a handle assembly (100), an elongated portion (200), an end effector (300), a visualization device (400), and a constant horizon mechanism (500). The elongated portion extends distally from the handle assembly and defines a longitudinal axis. The end effector is rotatable about the longitudinal axis relative to the handle assembly. The visualization device defines a visualization axis. A first portion of the visualization device extends through the elongated portion, and a second portion of the visualization device is disposed at least partially within the handle assembly. The visualization device is rotatable about the longitudinal axis relative to the handle assembly. The constant horizon mechanism is disposed in operative engagement with the visualization device and is configured to prevent the visualization device from rotating about the visualization axis when the visualization device rotates about the longitudinal axis.
