In the case of embedded objects or penetrating eye injury, the common advice has always been to bandage both the injured AND the uninjured eye. The rationale was conjugate gaze; if one eye moves, so does the other (we can’t move each eye independently like chameleons).

However, we now know that while our eyes do track together they also react to sound and other stimuli. There is actually more eye movement when vision is occluded, especially in children. There is no need to routinely bandage both eyes, unless both eyes are injured. Maintaining vision allows the patient to function and limits overall eye movement. Also, the eye moves more when closed than when opened, thus potentially doing more internal damage than of the uninjured eye were allowed to stay un-occluded.