。
She can only see things within a narrow range.
Literal
She [topic-は] narrow range [in-で] [only-しか] things [subject-が] cannot-see.
Two characteristic Japanese pieces. でしか~ない stacks the locative で (within X) with the restrictive しか and a negative verb — 'only within X (does the verb hold).' The literal force is 'except in a narrow range, things are not visible.' Note also 物が見える uses が rather than を with 見える ('be visible, can see') — this verb takes the seen thing as a が-marked subject, not as an object, since 見える is intransitive/spontaneous. Beyond the literal 'limited eyesight,' the sentence works metaphorically for narrow-mindedness — limited intellectual or social range of vision.