Final answer:
An ophthalmoscope is a medical device used to examine the structures of the eye. Its major parts include the light source, optical system, aperture, filters, and diopter wheel. The zero lens is used when examining the interior structures of the eye without magnification.
Step-by-step explanation:
Ophthalmoscope
An ophthalmoscope is a medical device used by healthcare professionals to examine the structures of the eye, including the retina, optic disc, and blood vessels. It allows for the detection of eye conditions such as cataracts, glaucoma, and retinal detachment.
Parts of an Ophthalmoscope
Major parts of an ophthalmoscope include:
- Light Source: Provides illumination for examining the eye.
- Optical System: Consists of lenses and mirrors that direct and focus light into the eye.
- Aperture: An opening in the instrument that controls the size and shape of the light beam.
- Filters: Used to modify the color of the light and enhance visibility of specific eye structures.
- Diopter Wheel: Adjusts the focus of the instrument to accommodate different levels of farsightedness or nearsightedness.
Zero Lens in Ophthalmoscope
The zero lens, also known as the plenary lens, is used when examining the interior structures of the eye. It provides a plane wave of light that is focused to create a clear image without any additional magnification.