The best way to begin evaluating the optic disc is to dilate the patient’s pupils with, for example, 2.5% phenylephrine or 0.5% tropicamide. If pupillary dilation is not feasible, the room lights should be darkened. Set the dioptric power on the direct ophthalmoscope to zero, instruct the patient to fixate on a distant target, and elevate the patient’s upper lid with your thumb. Gradually approach the patient’s eye and aim the beam 15 degrees nasal to the patient’s line of sight, toward the optic disc. As you approach, dial in whatever dioptric power is needed to keep the optic nerve in focus. If you cannot locate the optic nerve, ask the patient to look directly at or past your ear. You should assess cup- to-disc ratios and look for thin areas in the rim, disc hemorrhages, and asymmetry.