The external examination will most likely follow your preliminary tests. With the use of a penlight and no magnification, your doctor inspects the external structures of the eye, including the eye itself, lids, and other external structures.
A slit lamp bimicroscope is used to externally examine the eye with magnification. This device consists of an illumination system (a bright focal light with a variable aperture and slit mechanism), observation system, and other mechanical attachments. The magnification of the observation system can be varied depending on what the practitioner is inspecting. The patient sits in front of the instrument with his or her head on a headrest. By adjusting the angle of illumination and magnification, the doctor can view most external aspects of the eye in great detail.