The distance between your eye and the eyepiece is called "eye relief." Extended eye relief is one of the three most critical performance factors, along with magnification and field of view, especially for those who wear eyeglasses in the field.

някои може ли да обясни повече за този параметър кое по добро
по малкото или по голямото разтояние
и какво влияние оказва ?

Meopta Artemis 2000 4x32 - Exit pupil distance: 80 mm
Meopta Artemis 2000 3...9x42 - Eye relief: 75 mm

Leupold Vari-X 3-9x33mm Adj. Obj. EFR Compact - Eye Relief (mm): 102(3x) 102(9x)
Leupold European-30 3-9x40mm - Eye Relief (mm): 107(3x) 94(9x)