For vitreous surgery, there were two approached to deliver an indirect image of the fundus. Malbran and Dodds first reported the use of the Rodenstock Panfunduscope lens and this was later modified by Spitznas to make it more suitable for intraoperative use. Landers also developed an indirect vitrectomy lens but its resolution was insufficient for delicate epiretinal membrane dissection. Dominguez first proposed the use of a +30 Diopter lens for intraoperative fundus viewing and cinematography. Other surgeons found the Volk 60 D lens to be more optimal.
All of these people learned to work with the inverted image appreciating the wide field of view. Spitznas and Reiner made a significant step forward by the introduction of the Stereo Diagonal Inverter and the Binocular Indirect Ophthalmicroscope. The concept of binocular indirect viewing became a practical method allowing the many advantages Spitznas has described previously at this meeting and in publications.
In 1989 in New York, Avi Grinblat began to develop a panoramic viewing system based on the concept of binocular indirect biomicroscopy viewing. The system has three components: a stereo image inverter, 2 wide field, indirect aspheric contact lenses and wide field illumination that fits through a single 20 gauge sclerotomy. The A.V.I. Stereo Inverter re-inverts the image and reverses it right to left using a high precision prism cluster. There is no appreciable light loss when switching between the modes.