Closed vitrectomy: the Grieshaber instrument.

Description of Grieshaber nibbler for closed vitreous surgery: tip diameter is 1.6 mm, cutting is by four exquisitely cutting blades mounted on axis supported at both ends. Control console determines mode and speed of rotation. Oscillating cutting mode is recommended. Infusion is at the instrument's tip instead of its side. Unusually powerful but adjustable endo-illumination is available through fiberoptics. The fiberoptics tip is shaped to facilitate its introduction into the eye. A separate channel permits suction reversal. Five brief case descriptions illustrate versatility of the instrument. Its main advantages are its exquisite cutting properties, its powerful and adjustable endo-illumination, and its tip-end infusion hole.