Dog eye

Swollen eyes, a symptom where the eye and/or eyelids appear abnormally enlarged, can be caused by a number of different underlying conditions, including allergies, insect bites or stings, injury, conjunctivitis, or glaucoma.

Sunken eyes (enophthalmos) in dogs is a symptom in which the eyes appear to be recessed into the skull.

Bulging eyes occur when one or both eyeballs are larger than normal (called ‘buphthalmos’), or when they are the same size as usual but the eyeball is protruding from the eye socket (called ‘exophthalmos’).

Dogs develop many different types of eye infections. When the eyelid, conjunctiva, cornea, or structures within the eye are affected, those are called blepharitis, conjunctivitis, keratitis, or uveitis respectively.

Carbon monoxide (CO) poisoning in dogs results from excessive exposure to CO gas. The presentation of CO poisoning varies depending on severity and progresses from weakness and breathing difficulties with bright red gums, to coma and death.

Blastomycosis in dogs is a systemic infection caused by the fungal organism Blastomyces dermatitidis. This fungus is found in contaminated soil across North America, frequently near water.

Collie Eye Anomaly (CEA) describes a hereditary eye condition in collie and sheepdog breeds. This condition results from poor development of the blood supply in the eye which can lead to detachment of the retina, loss of vision or complete blindness in some dogs.

Pheochromocytomas in dogs are tumors arising from the cells of the adrenal medulla, which produce large amounts of hormones, such as epinephrine. Nearly half of all cases are asymptomatic and the tumor isn’t detected until a post-mortem examination.

Cryptococcosis is a fungal infection in dogs caused by fungus from the  Cryptococcus genus. Exposure usually occurs through ingestion or inhalation of fungal spores found in soil or avian droppings.

Meningitis is an uncommon, potentially life threatening condition that refers to inflammation of the meninges. Meninges are membranes that cover the brain and spinal cord. 

Valley Fever is an infection by the fungus Coccidioides immitis in dogs. This species of fungus is commonly found in dusty, dry areas in southwestern USA, Mexico, and parts of central and south America.

Portosystemic shunt (PSS) describes the condition in dogs in which blood flow via the portal vein (a vessel that carries blood to the liver from the abdominal organs) bypasses the liver, emptying directly into the bloodstream. 

Lenticular sclerosis in dogs is a normal part of the aging process in which the lens of the eye (the structure that focuses light onto the retina) hardens and thickens. This causes a bluish, cloudy appearance to the lens. 

Uveodermatologic syndrome in dogs is a rare grouping of symptoms that results from the autoimmune system attacking the pigment-producing cells in the eyes, hair, and skin. Symptoms include reddened, cloudy, painful eyes with diminished vision, and whitening of the coat and skin.

The pupil is the dark circle located at the center of the iris (the colored portion) of dogs’ eyes. The size of dogs’ pupils varies depending on light levels. When one or both eyes dilate (when the pupil becomes larger), this is called mydriasis.

Keratoconjunctivitis sicca (KCS) refers to an eye condition in dogs commonly referred to as “dry eye.” KCS causes decreased watery tear production, which leads to inflammation of the eye and surrounding tissues.

Blindness refers to loss of vision, either due to a problem within the eye itself, or within the nerves or brain affecting the processing of visual input from the eyes. Vision loss can affect one eye or both, and be partial or complete.

The retina is located at the back of the eye, and sends visual input to the brain via nerve impulses, creating the sensation of sight. If the retina detaches from the structures underneath it, it loses function, resulting in partial or complete vision loss.

Strabismus describes an uncommon disorder in dogs in which one or both eyes are not correctly aligned, giving the appearance of crossed eyes or eyes not pointing in the same direction together. 

Squinting (blepharospasm) occurs when the eyelids are lowered so that there is only a small space for the eye to look out of. Squinting is considered a symptom in dogs if it continues for a prolonged period and is not related to protecting the eyes from bright light.

Anisocoria is the term for unequal pupil size in dogs. One pupil is normal, while the other is either constricted or dilated. Anisocoria is common in dogs experiencing Horner’s syndrome, but it also results from a variety of conditions and injuries that either affect one eye directly or the parts of the nervous system that control pupil size.

Blepharitis describes inflammation of the eyelids affecting one or both eyes. Eyelid inflammation is a common presentation in dogs with a variety of underlying triggers.

Progressive retinal atrophy (PRA) is a disorder of the retina which eventually results in blindness in dogs. The retina is a layer of tissue at the back of the eye which translates signals from the eye into images in the brain.

A tumor is a proliferation of cells resulting in uncontrolled tissue growth. Primary eye tumors originate from within the eye, and secondary tumors spread to the eye from somewhere else in the body. Retroviruses, UV exposure, and genetics can predispose a dog to eye tumors.

Lead is a highly toxic heavy metal that can be found in paints, fishing tackle, ammunition, drapery weights, and old toys produced prior to the late 1970s. When lead is ingested or inhaled it damages blood cells and circulates throughout the body where it causes widespread damage.

Coloboma describes the presence of an abnormal hole, or thinning, in part of the eye. Colobomas are rare in dogs but, where present, are most commonly found in the iris and eyelid margin.

Eye discharge or epiphora is a common symptom in dogs. Causes, as well as treatment of eye discharge, vary greatly. Eye discharge can present in various ways including clear water (tears), crust-like formation on the inner corner of the eye, reddish discharge, white mucus, and yellow discharge.

Dacryocystitis is inflammation of the tear sac. The tear sac is part of the system which allows the draining of tears inside the nasal passages. When tear drainage is obstructed, tears overflow from the eye and conjunctivitis develops. 

Dogs have a third eyelid, visible as a pink membrane mostly hidden under the inside corner of the eye. When the bulbous, dark pink gland of the third eyelid slips out of place and becomes visible, this is called a “cherry eye.” 

Cataracts are a loss of clarity of the lens of an eye. They are typically easy to recognize, looking like a white or crystalline opaque color blocking part of the pupil behind the iris.