Final answer:
Before using an ophthalmoscope for an eye exam, a nurse checks focus adjustment, aperture selection, and filter selection to ensure an accurate and effective examination.
Step-by-step explanation:
Before beginning an eye exam with an ophthalmoscope, a nurse must check three key mechanisms to ensure the equipment is ready for use and the examination is conducted properly. These mechanisms are:
- Focus Adjustment: The ophthalmoscope has a dial that allows the user to adjust the focus to compensate for refractive errors of both the patient and the examiner's eyes. Proper adjustment is crucial for obtaining a clear view of the eye's internal structures.
- Aperture Selection: Apertures control the size and shape of the light beam going into the eye. The nurse selects the appropriate aperture size to match the examination needs, such as a smaller beam for a dilated pupil or a larger beam for an undilated pupil.
- Filter Selection: Different filters can be used to enhance various features within the eye. For instance, a green filter can increase the contrast of blood vessels, while other filters may help in the examination of the optic nerve and retinal layers.
These checks are performed to ensure accurate assessments during the eye exam, which is important for detecting diseases such as glaucoma and ensuring proper vision correction and general eye health.