Hi there,
I would like to help you. In a situation where a dog has a swollen eye, he needs to see a veterinarian promptly. I don't know what time zone you are in, but if you can get him to a vet today before your vet closes that would be best. If it is too late already, then you may need to see an emergency clinic tonight!
I strongly suspect your puppy has a corneal ulcer. This can be caused by a scratch on the eye - either in a tussle with another dog, or on a twig, or on a sharp object in the home. Chihuahuas are prone to them because their eyes are so prominent. Corneal ulcers are serious and need prompt treatment. Also, they are very painful. Just think how uncomfortable your eye is with an eyelash in it, and then imagine what it would be like with a cut on it!
When I have a patient with this problem come into the clinic, I do a full opthalmologic exam. I might put local anesthetic in the eye to make it painfree so I could open it to examine it closely. After an initial look, I would stain the eye with fluorescein dye which sticks to any parts of the eye that are damaged. This dye glows under a black light. Thus, you can easily see where the damage is.
If there was indeed a corneal ulcer, I would start the pet on antibiotic drops or ointment. If there was a lot of inflammation (uveitis) I would also start an ointment to dilate the pupil. I would also suggest the patient wore a cone on his head until the eye is healed so he could do no further damage (definitely he will think this is adding insult to injury!). I would have my patient come back in a week to check that things had healed up properly.
I will include a link with more information:
http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=554
In short, I think your pup has a corneal ulcer. It is urgent that he see a veterinarian promptly!
Good luck with him!
If this has been helpful, please hit the "Accept" button. I will still be here to provide further information if you need it.
Fiona
Veterinarian
15 years experience as a companion animal veterinarian in British Columbia, California and Ontario