Apple's iPhone Duo does not support FaceTime Eye Contact because its under-display camera design prevents the feature.

Users of the iPhone Duo discovered the Eye Contact option missing from FaceTime settings when making video calls.

Apple's Eye Contact uses machine learning to adjust the user’s gaze so it appears they are looking directly at the camera.

The absence of a Face ID 3D sensor is not the primary explanation; iPhone SE models that lack the 3D sensor still support Eye Contact.

Experts say the internal under-display camera's placement on the right side of the screen likely makes correcting oblique and lateral viewing angles far more difficult than the vertical deviations typical on conventional phones.

The Duo's foldable structure also changes the camera angle relative to the user's eyes depending on whether the device is open or closed.

Apple has limited eye tracking functions to the device's fully open state and has not published an official technical explanation for removing FaceTime Eye Contact.