It's very important to take your dog to the vet immediately. Swollen eyes can be a sign of a serious medical condition. Some possible causes include:
* Allergies: Pollen, dust mites, and other allergens can cause eye irritation and swelling.
* Conjunctivitis (pink eye): This infection can cause redness, swelling, and discharge.
* Corneal ulcers: These open sores on the surface of the eye can be very painful and lead to swelling.
* Glaucoma: This condition involves increased pressure inside the eye, which can damage the optic nerve and lead to blindness.
* Trauma: A blow to the eye or a scratch can cause swelling.
* Foreign objects: A piece of debris or grass stuck in the eye can cause irritation and swelling.
Please don't hesitate to seek veterinary care as soon as possible. Your vet can diagnose the cause of the swelling and recommend the appropriate treatment.