Recurring conjunctivitis isn't that common among *our* furry friends (more common in Poodles and spaniels, according to the web) however since it is recurring, you need to find out the cause and then determine a corrective approach.
Take a look at WebMD (one of my favourite spots for these type of problems, btw) note that it has an autoplay video so you might want to check your volume level.
I think, at this time, my response would have to be to go back to the vet. A response of "it's not cherry eye" (red eye / pink eye all synonyms for conjunctivitis) would have me asking "Well, if it's not pink eye then what is it and how do we stop it?" Since there are many things it could be - some minor and some, apparently, potentially much more severe - your vet might suggest a visit to a veterinarian optometrist.
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“Properly trained, a man can be dog’s best friend.”
Corey Ford .