'eye-soothing' is a Modern English compound formed from the noun 'eye' and the present participle 'soothing', where 'eye' comes from Old English 'ēage' meaning 'eye' and 'soothe' comes from Old English 'sōthian' meaning 'to calm or make true/soothe'.

'soothe' developed from Old English 'sōthian' through Middle English forms such as 'sothen'/'soothen' and into modern 'soothe'; 'eye' derives from Old English 'ēage'; the compound 'eye-soothing' arose in Modern English by combining the noun and participle to describe something that soothes the eye.

Initially the root idea was 'to calm or make true/soothe', and when combined as 'eye-soothing' it came to mean 'making the eye calm' — now used as 'visually pleasant or gentle to look at'.