Dogs, just like humans, are at the mercy of a good range of eye diseases that range in severity from minor conjunctivitis to ocular cancers. Understanding the difference between an ordinary and an ill dog eye is critical in order that you can recognize problems with your dogs eyes before they get even more severe and get the correct treatment when necessary.

There are many sicknesses or conditions that could affect the external eye, which includes the eyelids and conjunctiva, the cornea, and the sclera. Diseases of the external eye are very common, much more so than those of the internal eye. Bacterial contagions of the conjunctiva or cornea, called conjunctivitis and keratitis respectively, regularly cause redness and a thick, mucous discharge from the eye. Conjunctivitis will also cause distended eyelids and exaggerated redness on the inside of the eyelid. Traumatising injuries such as corneal ulcerations or abrasions will often cause excessive watering of the eye and agony.

A dog with a unpleasant eye will generally squint and rub or paw at the concerned eye. Dry eye, a condition which causes the tear gland to malfunction and makes the eye excessively dry, causes a surplus of thick, stringy mucous across the eye. Dry eye also in time causes melanin pigment to be deposited in the cornea secondary to chronic inflammation. This black pigment can be exceedingly obvious in some dogs, and can eventually cover the entire cornea. Illnesses of the external eye are generally quite straightforward to diagnose through tests like a fluorescein stain, which diagnoses corneal ulcers, and a Schirmer tear test, which helps to disqualify dry eye. Treatment of external eye sicknesses is generally in the guise of topical drops or ointments.

Diseases of the internal eye are even less common, but often more serious and more likely to threaten vision and integrity of the eye than external eye illnesses. It is mostly much more difficult to recognize issues with the interior of the eye. Redness of the inner eye, which is known as uveitis, can occur secondary to a number of issues, and is usually recognised because of an abnormal reddish tint to the iris or inside of the eye. Glaucoma, which is just an increased pressure inside the eye, may also be secondary to several underlying causes. It is generally spotted by the dog keeper when the eye becomes enlarged due to the excess pressure. Sicknesses of the retina, such as atrophy or retinal detachment, are quite serious in that they threaten to render the dog permanently blind. Sadly, the first outward clinical sign of retinal illness is usually blindness or partial blindness.

Understanding the diverse symptoms of eye illnesses in dogs is necessary to all dog keepers so that if a problem appears it can be addressed prior to it becoming severe. If you spot any signs of external eye disease, for example watering, discharge, squinting, or pigment, or of internal eye disease, for example an enlarged eye, an abnormal hint to the iris or inner eye, or blindness, you need to seek vet care right away.

Cathy Doggins is the most active contributor to the Dog Health Guide, a leading source of info on canine sicknesses and conditions. She has written many articles on dog eyes. When not caring for the canine members of her family, Cathy can be found volunteering at a local shelter or talking for animal rights.