Final answer:
Filtered lenses with an appropriate shade rating are essential for tasks such as welding or viewing solar eclipses, where exposure to intense light and radiation is present. Regular sunglasses or glasses do not offer sufficient protection for these types of activities that require specialized protective eyewear.
Step-by-step explanation:
Filtered lenses with the appropriate shade rating number are required for work involving exposure to intense light sources, such as welding. These activities emit harmful levels of light and radiation, necessitating the use of special protective eyewear. Ordinary glasses and sunglasses do not afford sufficient protection.
For example, welders' goggles are equipped with filters that have the correct shade rating to protect the eyes from the harmful ultraviolet and infrared radiation produced during welding. Additionally, individuals viewing solar eclipses need specially designed eclipse glasses with the appropriate filters to prevent retinal damage.
Modern lenses can have complex designs, including special coatings, materials, and technologies like photochromic lenses that adapt to changes in light exposure, to provide protection and clear vision in various lighting conditions. However, for professions or tasks like welding or directly observing an eclipse, specific protective eyewear with the correct shade rating is critical.