Third eyelid still showing

Would anyone happen to know why would my cats third eyelid still be showing after medicine? We have had a rough 6 weeks and I have spent quite a bit of money on vet bills. It first started with my Benjamin throwing up. I took him to the vet they did X-rays and blood work and determined it was either a virus or something he ate. They gave him a shot and he was fine. A few days later my girl Caya's eyes looked terrible. Watery and cloudy with the third eyelid showing. I took her to the vet. She checked out fine but they thought maybe she was getting a virus so they gave her a shot. A few days after that Benjamin's eyes looked bad and Caya's were no better. We went back to the vet. They were given eye drops for an eye infection and turns out they had roundworms too. Got meds for that and treated all three of my kitties even though just two cats were affected. Their eyes improved only a little. Went back to the vet and they gave them antibiotics for ten days. Just gave the last dose yesterday and their eyes are better but not great. Seems like some times the third eyelid is barely visible and then later in the day you can see it. I don't know what to do. I would take them back to the vet but it seems like we have tried everything. They are acting fine. Wild and bad as ever. And eating and drinking good. Will the eye issue correct itself?? Oh I almost forgot to mention that I am having itchy eyes too. That is pretty normal for me and allergy drops have helped. Could allergies be their issues?? I am ready to be done with these issues. Putting drops in a cats eye is next to impossible and me and my husband are scratched up head to toe. I would appreciate any advice or any input from someone who has gone through this too

my cat has eye issue too, but the third eyelids are not showing.

I just leave what I read on Internet these days, hope it will help.

If the eye problem is the only problem, the the drop and ointment will work, not a shot, or oral meds.

If there are other problems, you should to treat them all at the same time, to make your cat's eyes better. Like oral meds + topical meds.

And there are different kinds of infection: bacteria, needs antibiotic, follow the tips, don't stop it too early or use it for too long

                                                                          virus, needs antivirus, which help the situation but do not kill the virus

                                                                          Fungals, needs antifungals

And there are special bacteria too, like c felis, it's a bacteria but without cellwall, needs special meds, like erythromycin。

Because the normal drop stop the bacteria by destroy their cells, and doesn't work for those without cell wall.

And the showing of the third eyelid means your cat's unconfortble

Good luck.  

I should leave now and keep searching for my cat.