An ophthalmoscope is a medical instrument used by healthcare professionals to examine the interior structures of the eye, particularly the retina, optic nerve, and blood vessels. It consists of a light source and a series of lenses that allow the examiner to see through the pupil and into the eye. This examination helps in diagnosing various eye conditions and diseases. The ophthalmoscope can be handheld or mounted, and it often features adjustable lenses to accommodate different vision needs. By shining a light into the eye, the doctor can observe the health of the eye and detect issues such as diabetic retinopathy or glaucoma.