What tool does a physician use to examine the eyes?

The correct choice is the ophthalmoscope, which is specifically designed for examining the interior structures of the eyes, including the retina and the optic nerve. This tool allows physicians to visualize the back of the eye, which is essential for diagnosing various eye conditions and systemic diseases that can affect eye health.

In contrast, the otoscope is used for examining the ears and is not suitable for eye examinations. The sphygmomanometer measures blood pressure and has no relevance to eye examinations. The stethoscope is utilized to listen to internal body sounds, such as heartbeats and lung sounds, making it inappropriate for assessing eye health. Therefore, the ophthalmoscope is the essential instrument for ocular inspection, aiding in accurate diagnosis and treatment planning.