Final answer:
The second ADD segment of trifocal glasses provides clear vision at intermediate distances such as computer use or viewing a car dashboard.
Step-by-step explanation:
The second ADD segment of a trifocal lens is designed for intermediate viewing distances, typically around arm's length. This segment allows for clear vision when performing tasks such as viewing a computer monitor or dashboard in a car, which are too far for the reading segment and too close for the distance segment. Trifocal glasses aid those with presbyopia by providing three levels of magnification, each tailored for different visual ranges.