Take him to the vet. It could be conjunctivitis, highly contagious.
PS: I doubt very much that his condition has anything to do with his kibble.
https://www.vetinfo.com/diagnosing-dog-eye-discharge.html
Dog eye discharge can be alarming to any dog owner. It can be caused by something as simple as environmental allergies or as serious as corneal ulceration. Whatever the cause, eye discharge should be addressed and treated before the condition becomes more serious, causing the loss of vision or possibly the loss of an eye. Tearing and discharge is the canine eye’s way of ridding itself of any irritant that may exist on a day to day basis or a chronic eye problem.
Determining the Seriousness of the Discharge
Ocular discharge can occur gradually or can develop very suddenly in dogs. A general guideline is that the more discharge there is, the more serious the condition of the eye. Other symptoms that indicate the need to be seen by a veterinarian for potential treatment are:
Eye discharge is thick and mucous-like
Eye discharge is yellow or greenish
Eye discharge is bloody
Tissue surrounding the eye is red and irritated
Causes of Eye Discharge
Eye discharge can be caused by any number of irritants. Causes of discharge include, but are not limited to:
Abcess or infection in the upper back teeth
Allergies
Anterior uveitis or swelling of the iris and surrounding portions of the eye
Blepharitis or inflammation of the eyelids
Cherry eye or protrusion of the tear gland of the third eyelid
Conjunctivitis
Deformities in the tear drainage pathway or inflammation, blockage or narrowing of the tear drainage path
Deformities, wounds or tumors of the third eyelid
Dry eye
Eyelashes growing out from the inside of the eyelid, irritating the cornea
Eyelid defects
Glaucoma or elevated interior eye pressure
Inflammation of the cornea
Inflammation, infection or tumor in the soft tissue around the eye
Scratches, cuts or ulceration of the cornea
Trauma to the area around the eyes and nose
Diagnosing Eye Discharge Problems
While a general practice veterinarian has some of the tools required to conduct a canine eye exam, a veterinary ophthalmologist will have the full spectrum of equipment required to conduct a full ophthalmic examination or specialized testing, should they be required. Some of the tests that may be conducted:
A Schirmer tear test, which determines whether tear production is reduced, normal or elevated.
Detailed examination of the canine eye interior, looking for inflammation, bleeding or other problems.
Fluorescein staining, to determine if there is ulceration or erosion of the cornea.
Tonometry, which determines if the interior eye pressure is reduced, normal or elevated.
If indicated, a veterinary ophthalmologist may also require cell analysis collected from gland openings or from the cornea or other eye tissue. Other procedures may also be required to determine if the tear ducts are blocked or if there are underlying systemic causes for the eye discharge.
Some dog breeds are known to have discharge and tear staining from their eyes. If your dog is one of these breeds and the tearing is a concern, have it checked out to ensure there isn’t an underlying problem. If your dog develops discharge, it is important to have the condition checked out, especially if the tearing is excessive, thick, or appears to be infected or bloody. By taking these precautions, you can help ensure your dog keeps his healthy eyesight throughout his lifetime.
