Certified Ophthalmic Medical Technologist (COMT) Practice Exam

What kind of microscopy is required to view most viruses?

1. Standard optical microscopy

2. Electron microscopy

3. Fluorescent microscopy

4. Phase-contrast microscopy

The correct answer is: Electron microscopy

To view most viruses, electron microscopy is essential due to the extremely small size of viruses, which typically range from 20 to 300 nanometers in diameter. Standard optical microscopy, while useful for observing larger cellular structures, cannot achieve the resolution necessary to visualize viruses because it is limited by the wavelength of visible light, which is much larger than the size of most viruses. Fluorescent microscopy allows for the visualization of specific components within cells using fluorescent tags, but this method also cannot resolve objects as small as viruses. Phase-contrast microscopy enhances the visibility of transparent specimens but is likewise insufficient for observing the fine details of viruses. Therefore, electron microscopy is the only technique that provides the high-resolution imaging required to study viral particles effectively.