Final answer:
An ophthalmoscope is a medical instrument worn on the head that enables professionals to view and examine the back of the eye, particularly the retina, by magnifying the structures through lenses.
Step-by-step explanation:
An instrument that is worn on the examiner's head and used to view the back of the eye is known as an ophthalmoscope. This device allows healthcare professionals to examine the retina and other structures located at the posterior part of the eye, which is essential for diagnosing various eye conditions.
Ophthalmoscopes function similarly to microscopes in that they use lenses to magnify the structures of the eye. However, unlike traditional microscopes, they are designed specifically for the complex anatomy of the eye. They utilize direct light to illuminate and examine the back of the eye, providing a clear view of the retina, blood vessels, and optic nerve. The eyepiece, like that found in microscopes, is the lens closest to the observer's eye when examining the patient.
Advancements in optical technology have made it possible for optometrists and ophthalmologists to detect subtle details in the eye that would otherwise be imperceptible. Understanding how optical instruments like ophthalmoscopes work is fundamental in fields such as medicine, especially in specialties focusing on eye health and vision care.