What kind of eye drop will treat eye worms in chickens?

[Luckybaby]

One of my free range chicken have eye worm. It is not easy to notice it, unless I look on the area near the third eyelid of the chicken for several seconds. It is blinking a lot and it's eyes are watery, but I didn't see any pus on the third eyelid. I am putting vetrx on the cleft of it's mouth since 4 days ago, and the eye worms are still in there. I only see something come out(pus or worm) from it's eye on the following day, after I put pure vetrx on the cleft. I didn't see anything unusual coming out of the eye, after I put a solution(vetrx and water) of vetrx on the cleft of the mouth. I researched about treatments for eye worm, and found out that ivermectin eye drops treat chicken eye worm. There are many kinds of ivermectin injectible that is for sale. Should I use the one for cattle and swine, or the one for horses? Should I put pure ivermectin on the eye, or dilute it on water? Also, how often should I put ivermectin on my chicken's eye? I also want to know what other safe medication works for chicken eye worm, and what is the correct method for treating them with it.

 

[Eggcessive]

Eye worm is very rare. Here is a short thread on what to look for and how to treat it: https://www.backyardchickens.com/t/...mycoplasma-cannot-figure-this-swollen-eye-out