Hi there,
I am new to this bringing on a 'spare' lamb myself, but with the several I have had (mostly scraps, half have not survived) I have been quite sure two were blind. One had inturned eye lashes - open the eye up wide with your fingers - you may see ingrowing fine eye lashes (mine were at the bottom pointing up). A few attempts at teasing them out with salt water and cotton wool balls seemed to do the trick. Both lambs appeared blind initially - or at least partially sighted for a while - now they seem ok. Aparently the lashes can abbraise the eye causing temporary loss of sight. This might be it, possibly?
The other little one sounds very much like watery mouth (ecoli) to me. I have one with the same symptoms, have taken her to the vet and she has had another dose of anti bio's and is on electrolytes briefly. If her tummy is tight, like a drum, or rattles like a balloon full of water I suspect this is what it is. Vet asap! Not great prognosis though. I've lost 3 and am still battling with the forth.
Gah, lambs, they are soooo tricky.
Talking of which, I can hear one shriekking in the field next door. Best go investigate =/