There are many issues that might cause problems with your cockatiels eyes. Poor nutrition, an infection or injury are the most common problems when it comes to eye healthcare with your cockatiel.
Mites can also damage your cockatiel's eyes as well a Vitamin A deficiency.
From time to time a foreign particle like dust or a crumb from a cracker can cause eye irritation.
If your cockatiel eyes are frequently blinking, closing any eye, redness, discharge, or swelling of the eyelids, there should be reason for concern. Infections associated with bacteria seem to be the most relevant reason among cockatiels when it comes to eye issues. From time to time a foreign particle like dust or a crumb from a cracker can cause eye irritation. Other types of infection like a sinus problem can cause the eyes to look 'puffy.'
If you suspect your cockatiel has an eye infection, It is likely that your vet will prescribed Polysporin eye drops, but you should consult the vet first. If they want to test what type of bacteria is causing the infection, the eye drops will nullify the test.
Until the vet can see your cockatiel, use sterile "artificial tears" eyedrops to keep the eye lubricated and comfortable.
As always the information offered here is to provide guidance and is not intended to be a substitute for the good advice provided by your own avian vet. When in doubt always consult your own veterinarian.
Conjunctivitis is contagious among birds, but does not pose a threat to humans or domestic pets.