| The advantages of the A.V.I. Panoramic Viewing
System in Vitreous Surgery by Stanley Chang, M.D.
|1. With the advent of the transparent image inverter
and two miniaturized contact lenses a high-resolution view of the entire
fundus was made possible. Panoramic views through this system allow the
selection of 68-degree field of view up to the equator or a 130-degree
field of view up to the ora serrata. Current direct biomicroscopic viewing
allows only a 20 or 35-degree field of view. Other wide field systems
allow only a 70-degree field of view, which does not offer the precision
and higher resolution image of the A.V.I. system. This approach added
new dimentions to the surgical capability in complex cases of retinal
| 2. Greater depth of focus compared with conventional
direct viewing system using plano-concave contact lenses.
|3. Integration with conventional plano-concave contact
lens system, so that one lens can be removed and replaced by another lens
easily. The miniature indirect lenses are compact, lightweight in comparison
to other panoramic lenses. Thus their size allows manipulation on the
eye without interfering with placement of the surgical instruments.