d be concerned that this is the start of an eye
infection, especially since the first infectious conjunctivitis for
kittens with Feline Leukemia hits between 4-6 weeks of age. (some 80% of the stray cat population has it).
I'd consider taking the kitten to the vet, especially if there's oozing about the eye, or swelling.
On another note, if you contact your local animal shelter or rescue group, some of them do provide "safe trap" cages to catch stray kitties.