Hi Pedwardine, hmmm well...I have over the years picked up four lambs that have been totally blind from pinkeye, and definitely don't recommend leaving it to run its course if it is really bad and making them blind or ulcerated.
Most lambs will get it not too badly and come through fine, others don't. It looks incredibly uncomfortable and yes is distressing to see. Of course some of the lambs will come right on their own, but if they don't you end up with eyes that have ulcerated and permanently blind sheep like my Alice.
The treatment I did was over two months of DAILY treatment with orbinan (these are the blind ones, the ones that are not too bad can probably be much less often and just over a week or so- maybe two or three treatments) On my friends farm the orphans often get it because they are confined to a smaller area, and this is usually all it takes to fix the problem. These ones clear up within two weeks. However in saying this, even though these lambs are all sleeping and feeding together it doesn't mean they all get it.
Three of the four blind ones got much of their sight back, except Alice is blind as she was left too late without any treatment and Biddy is blind in one eye that ulcerated. That eye is kind of huge now, healed up (the vet had to sew it shut until it healed) Initially i used a powder spray given by a vet that deals only with farm animals and it did nothing. The vet I go to now, said orbinan would fix it and it did.
One that was very bad had a few injections over the period of intracillan LA as well - assume what is suggested above by Blacksheep is similar. i would always talk to the vet about doing that in the future, now i know it helps.
In-curving eyelashes can also make a lamb susceptible to it, one of the lambs (Biddy) had this and the vet injected saline i think it was into the lid to stop it curving in. This was sooo much easier then pinching it to uncurl it and so much less painfull for the lamb. However it may be a bit difficult to take all the lambs to the vet when there are lots of lambs. Although you sound like it is just a few that have it. Its important to check that they don't have in-curving eyelids if they have pinkeye
If your lamb is totally blind, I do suggest checking if the orbinen you have should be used daily, as the stuff we have here in NZ is. and I think i was applying it twice a day. Id squat down tip the lamb up hold its head firmly against my chest so it cant move it hold the lower eyelid open a bit and put a generous squirt of orbinan in. If i was having problems with the orbinan tube I would have very clean hands and put a big bit on my finger and into the eye. Was very easy. May not be quite as sterile as one would like, but better than risking a poke in the eye.Orbinan is cheap here - in terms of saving sight its very cheap, but yes the oozing out is annoying.
It takes at least three or four weeks to get the sight back. the lamb will get used to the routine, but it is alot of work. But once you are in a routine it only takes a couple minutes, and better than a blind sheep. Its actually wonderful to see them start to get their sight back.
It spreads badly only when they are confined closely together (like orphan lambs often are) so it doesn't mean everyone will get it when they are out in a paddock
If your lamb is blind she needs a safe paddock so she can get used to it, and perhaps a friend or maybe the other with pink eye. Separating them means you are less likely to have it go through the lot.
oh such good luck to you with your wee blind one, and don't panic the others probably wont all get it.