Funduscopic systems: a comparison of magnification.

The magnification properties of several funduscopy techniques are compared. These techniques include direct and indirect ophthalmoscopy, and slitlamp funduscopy with accessory lenses, such as the Hruby lens and fundus contact lens. Two new approaches are taken in the determination of funduscopic magnification. As a standard, the magnification of direct ophthalmoscopy is assumed to be 1.0X. The magnification provided by other methods is compared to this to yield relative magnification.