The classic Goldmann contact lens.

Zone 1 = Lens (1)
Examination of the ocular fundus in the 30° zone.

Zone 2 = Mirror (2) with a declination of 73°
Observation of the zone outside of the 30° range

Zone 3 = Mirror (3) with a declination of 66°
Observation of the peripheral sections of the ocular fundus, and under favorable conditions, also of the ora serrata.

Zone 4 = Mirror (4) with a declination of 59°
Observation of the vitreous body and ocular fundus sections neighboring the ora serrata as well as a gonioscopic examination.