It looks to me like they have a mild respiratory disease, which Corid does not treat (it is used for Coccidiosis, a protozoan parasite infection). The probiotics and electrolytes that you gave them are good supportive measures, but they won't cure this disease, either. You probably need an antibiotic.I'm not sure what antibiotics are available in your area, but I would look around at some livestock supply stores or possibly regular pet supply stores for antibioitics like Tylan50, tetracycline, or oxytetracycline (Duramycin, Terramycin, etc.). Or you could search and order antibiotics online.
It is possible, though, that the disease is viral. In that case, antibiotics won't work, and all you can do is wait for the birds own bodies to fight the infection off. Keep giving supportive care (vitamins, warmth if necessary, cleanliness, etc.) for a while longer.
The only other thing I can think of is that it is not a disease, but simply eye irritation caused by some sort of chemical, dust, or ammonia from their droppings. I would make sure their housing is clean, that harmful house cleaners or pesticides aren't being used nearby, and that their litter isn't full of excessive amounts of dust.
Good luck!
