I can't see anything there that might suggest a disease.
You'll need two people to have a good look under the eylids.
People do use saline wash. My vet says no and the oil based nature of the eye lubricant says no as well. Plain water boiled and let to cool is best.
With someone else holding her, apply slight downward pressure with one finger just below the lower eyelid. This will pull the eyelid down and once you've found the right pressure spot, the eylid should come down far enogh to check for debris under the lid.
Check around the eye, underneath the feathers to see if you can see a cut or a bruise. A good magnifying glass helps here.
There are two eye care products I use in this list. I've used both on chickens. One drop under the eylid!
https://www.backyardchickens.com/articles/the-chicken-keepers-health-armoury.75220/
If there is any sign of an infection Tobrex is what my vet recommends.
https://www.rxlist.com/tobrex-drug.htm
Edit.
You should have on hand everything or it's equivelant on that list if you're going to keep chickens.
The heavy drugs such a antibiotics should be prescribed by a vet and got when necessary, not kept on hand.
She is lovely.
(Mentally, as well as physically).
