A tip part (5) for a vision device. The tip part (5) comprises a housing (6, 7) adapted for accommodating a vision receptor (10). At least one light guide (15) of a transparent material having a predetermined length is arranged between at least one first light reception end (16) comprising an end face (16) with an essentially plane surface perpendicular to the longitudinal direction adapted for receiving light from a light source and at least one second light emission end (17) adapted to emit light.The light guide (15) has varying cross-sectional area along the predetermined length, so that the predetermined length comprises an expanding sector and/or a narrowing sector in which the light guide has a varying cross-sectional area along the predetermined length.
