5
Description of the IVS2 and its Functions
Vitreous surgery is often carried out with plano-concave lenses, biconcave
lenses and wide field lenses. Combination contact lens systems and indirect
ophthalmology lenses provide an even greater field of view of the fundus.
However, the image they provide is inverted which is extremely difficult to use
during vitreous surgery.
The IVS2 re-inverts the image of the contact lens systems such as those made
by Ocular Instruments. It frees the surgeon's hands and allows him to work in
the vitreous with an upright, non-reversed image under panoramic conditions.
During surgery, operative work is performed both outside and inside the globe.
Since the fundus is observed through a contact lens, it is necessary to be able to
move back and forth smoothly and quickly between the upright and the
inverted image. This function is performed by the IVS2.
The IVS2 consists of an optical system which can be rotated into the optical
path of the microscope to produce a complete image re-inversion. The image
inversion can be turned on and off by turning the adjustment knob (Figure 1,
No. 3) capped with the rubber adjustment knob (Figure 1, No. 4) clockwise
until it clicks into position. The position of the optical system is noted by the
indicator in the glass window (Figure 1, No. 7). It is centrally located on the
front of the IVS2 just to the left of the adjustment knob. If the image in the
window is yellow, the optical system has been swung to the side and image
inversion is not occurring. The “O” indicates the image inversion is inactive.
