What does the term "maximum distance runway or lights can be seen" describe?

The term "maximum distance runway or lights can be seen" specifically refers to Runway Visual Range (RVR). RVR is a critical measurement in aviation, indicating how far a pilot can see the runway's lights or markings under specific weather conditions. This measurement is essential for assessing visibility during landing, particularly in low-visibility situations such as fog, rain, or snow, where traditional visibility measures might not provide complete safety information.

RVR helps pilots make informed decisions about landing when visibility is restricted. It focuses on the effectiveness of the lighting system used at the runway to guide pilots, which is why it is crucial for runway operations. Unlike other visibility terms such as variable visibility or sector visibility, RVR is specifically tailored to runway conditions and operational safety.