Auxiliary lenses in fundus biomicroscopy--a comparison of fields of view.

The use of the biomicroscope in fundus examination requires an auxiliary lens to overcome the high focal convergence of the eye. This study presents the results of subjective field of view determinations with a variety of auxiliary biomicroscopy lenses. Direct/mirror view Goldmann type contact lenses demonstrated the smallest field in the range of 25-30 degrees. Indirect view pre-corneal condensing lenses were about twice this amount in their field. Wide field indirect view lenses with contact lens elements (Rodenstock Panfunduscope, Mainster retinal lens, Volk Quadraspheric) range between 85 and 125 degrees d of field. The use of each type of lens in routine and specialized examination of the fundus as well as in photocoagulation are discussed.