Owlie, Solo,
Eye diseases in wild birds can be caused by infection with bacteria, viruses or other pathogens as well as injuries due to accidents, tumors, metabolic diseases, vitamin A deficiency or genetic factors. Due to the multitude of possible causes, it is important to clarify the background for the disease in each individual case as precisely as possible.
These can be causes:
Chlamydial infection
Hack and bite wounds on the head and eyes
Corneal inflammation and clouding of the eyes
Parasite infestation on the eyelids and around the eyes
Injuries to the eyes and eyelids
Growths on the eyelids (papillomatosis)
Chlamydial infection
A common cause of eye diseases in pet birds are pathogens from the chlamydial family. They cause swelling of the eyelids, the animals close their eyes from the pain caused by the infection, and often they scratch themselves so often that the surrounding feathers fall out. Sticky secretions also often come out of the eyes.
Disputes can sometimes arise among wild birds, especially during the breeding season.
Often two opponents clash who want to claim the same territory for themselves. The animals chop each other with their beak and often aim at the head region. Serious injury to the area around the eyes can result. In many cases, such wounds are accompanied by torn feathers
German only!
http://wp.wildvogelhilfe.org/de/vogelwi ... ten/augen/
Indeed! I can imagine that it also stings a bit with a small egg tooth on a cheek 
asteria
- pinches of M15's feather
