X pattern
A form of incomitant exotropia where the outward deviation of the eyes increases in both upward and downward gaze compared to primary gaze. It is commonly seen in long-standing exotropias due to the leash effect of tight lateral rectus muscles restricting abduction in up and down gaze. X pattern can also occur in type 3 Duane retraction syndrome. Overaction of all four oblique muscles has been proposed as an underlying mechanism.