Noticeably; visibly; to an extent that the change or difference is clearly seen.
最近、彼の日本語力は目に見えて上達している。
Lately his Japanese ability has noticeably improved.
春になって庭の花が目に見えて増えた。
With spring, the flowers in the garden have visibly increased.
予算削減の効果は目に見えて現れた。
The effects of the budget cuts became visibly apparent.
トレーニングを始めてから体力が目に見えて強くなったと感じる。
Since starting training, I can feel my stamina has visibly strengthened.