What this suffix does
-sighted forms compound adjectives that describe both physical vision (the ability to see at certain distances) and the figurative capacity to see ahead in time or to perceive consequences. Shortsighted, farsighted, and nearsighted cover the physical spectrum; but farsighted, shortsighted, and clear-sighted also describe whether a person, policy, or plan can anticipate the future wisely. This double register — literal eye function and metaphorical intellectual vision — makes -sighted one of the most versatile and expressive compound elements in English.