What is the primary effect of lacrimators?

The primary effect of lacrimators is indeed that they are local irritants that affect the eyes. Lacrimators, commonly known as tear gases, are chemical agents designed to irritate the mucous membranes, leading to tearing and a burning sensation in the eyes. This effect is intended to temporarily incapacitate individuals, causing them to experience discomfort that can impair vision and trigger an instinctive reaction to escape the area where the agent is present.

While lacrimators may have some secondary effects on other systems, such as causing a runny nose or mild respiratory irritation, their hallmark effect is the acute irritation of the eyes, making it difficult for a person to see clearly and effectively respond to their environment. This is why the correct answer focuses specifically on their action as eye irritants.