This is the 3800th most frequent Korean word.
시력을
"시력을" means "eyesight" or "vision" in English.
In this sentence, '시력을' refers to 'eyesight' functioning as the object of the verb '보호하려고' (to protect).
그는 시력을 보호하려고 규칙적으로 안과 검진을 받습니다.
He regularly undergoes eye check-ups to protect his eyesight.
Here, '시력을' is used as 'eyesight' and acts as the object of the subtle action implied by '유지하는' (maintaining).
자연광이 시력을 유지하는 데 중요합니다.
Natural light is crucial for maintaining eyesight.
In this sentence, '시력을' again means 'eyesight,' acting as the object affected by the verb '해칠 수 있습니다' (may damage).