“cakkhusmiṁ” means “with regard to something seen”
“sati” is attention on it
“cakkhusamphassapaccayā” generation of “san” (lobha, dosa, moha) regarding what is seen
If one likes what is seen, that generates a sukha vedana (and one may crave it); if it is disliked one may generate a dukkha vedana (and rejects it); if one is not sure about what is seen (avijja) one may be confused about it (vicikicca).
The key is to learn about “samphassa”: “Search Results for: samphassa“