The slit-lamp examination looks at structures that are at the front of the eye (the anterior segment): The eyelid, the sclera (whites outer structure of the eye), conjunctiva (membranes lining the eyelid and sclera srface), iris (colored part of the eye), natural crystalline lens, and the cornea (thin transparent membrane that covers the iris and the lens). The slit-lamp is an instrument used with a high-intensity light source that can be focused to shine as a slit. It is used with the biomicroscope (an optical instrument that is like a microscope with two eyepieces).