Observation of the fundus of the eye with a biomicroscope. It requires an additional, usually hand-held, lens (+90 D, +78 D, +60 D, etc.) placed between the patient's eye (with the pupil usually dilated) and the slit-lamp, which is adjusted to be coaxial with the eye. This method provides a real, inverted and reversed stereoscopic view of the fundus. See illumination; gonioscopic lens; Hruby lens; slit-lamp.