Line-by-Line:
Alternating horizontal lines make up left and right eye images

LINES PER EYE = 540 FOR HD/1080 FOR 4K
TOTAL LINES = 1080 FOR HD/2160 FOR 4K
Top/bottom:
The upper half is the left eye and the lower half is the right eye

LINES PER EYE = 540
TOTAL LINES = 1080
Separate Left/Right:
The left and right eye views are separate video signals

LINES PER EYE = 1080