A slit lamp is a special microscope that enables your provider to see the structures in the front of your eye. A slit lamp uses an intense beam of light to illuminate your eye. Using this light, your provider examines the cornea, iris, lens, and anterior chamber of your eye. With additional lenses, your provider can also examine the back part of your eye, including your optic nerve and retina.
In many cases, providers use an orange dye called “fluorescein” when examining your cornea. The dye spreads across your eye to help your provider see any damage such as tiny cuts, scrapes, tears, foreign objects, or infections on your cornea. Your natural tears will wash the dye away shortly after the test.