Overview of Cloudy Eye in Dogs
A cloudy eye or increased opacity of the eye is associated with the reduced transparency of either the cornea, the fluid media within the eye, or the lens. In dogs, this change may be described as a “film” covering the eye or as an increased cloudiness within the eye. Cloudiness of the eye may or may not be associated with a reduction in vision.
The causes of a cloudy eye typically fall into one of the following categories:
- Cloudiness of the cornea, which may occur with corneal infections, corneal scarring, infiltrative inflammatory diseases of the cornea, fatty infiltration or calcium deposition within the cornea, or corneal edema (fluid accumulation)
- Cloudiness of the aqueous humor, which is the fluid that circulates within the front chamber of the eye. This may be due to the accumulation of white blood cells, protein, fatty lipids or blood.
- Opacification or whitening of the lens from cataract formation
- Disorders of the vitreous body, which is a gelatinous fluid between the lens and retina. These may include congenital defects, hemorrhage or inflammation.
What to Watch For
- Physical change in the appearance of one or both eyes
- Possible decrease in vision with changes in behavior
- Possible squinting. Some causes of a cloudy eye are painful; others are not
- Possible discharge from the eye
- Possible redness to the eye
Diagnosis of Cloudy Eye in Dogs
Diagnostic tests are essential in determining the precise cause of the cloudy eye. Tests may include:
- Complete medical history and physical examination
- Complete ophthalmic examination including fluorescein staining of the cornea, Schirmer tear test, tonometry, slit-lamp biomicroscopy and indirect ophthalmoscopy.
- Complete blood count (CBC) and serum tests
Additional diagnostic tests may include:
- Cytology, or microscopic examination of any inflammatory changes in the cornea
- Bacterial culture of an infected cornea
- Aspirate and analysis of any cloudy fluid from within the eye
- Gonioscopy of the normal eye if glaucoma is suspected
- Ultrasound examination of the eye if the retina cannot be examined
Treatment of Cloudy Eye in Dogs
Successful treatment depends on obtaining an accurate diagnosis as to what tissue of the eye is cloudy and what is the underlying cause of the problem.
Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up examinations can be critical to your pet’s health. Also, do not delay in bringing your dog to the hospital for initial examination as some causes of a cloudy eye may result in a loss of vision within a very short period of time.
In addition, do the following:
- Observe the eye at least twice daily. Signs that may indicate a worsening condition include more obvious inflammation (redness), increased or altered discharge from the eye, pain (usually evident as squinting) or loss of vision.
- If your dog’s vision is compromised, minimize stress and risk of injury by confining him/her to a safe area until the cause of the problem is determined.
- Do not allow your dog to rub or self-traumatize the eyes. To prevent self-inflicted damage you may need to obtain a protective collar (called an Elizabethan collar or E-collar) from your veterinarian.
- Do not administer human over-the-counter medicines such as Visine or other ophthalmic products designed to “reduce eye redness” or irritation as the underlying cause of the problem must be identified.
- Administer all medications as prescribed and alert your veterinarian if you have any difficulty treating your dog.
In-depth Information on Canine Cloudy Eyes
Numerous changes in the cornea of the eye may result in cloudiness, including:
- Corneal ulceration or infection from bacteria, fungi or yeast
- Corneal scarring from eyelash disorders; inrolling of the eyelids; exposure of the cornea to foreign bodies, drying, heat, smoke, chemicals; eye injury or trauma; inability to blink properly and protect the eye; decreased sensation on the surface of the cornea and resulting poor protection of the cornea; prior corneal surgery
- Corneal inflammation from inadequate tear production (keratoconjunctivitis sicca; dry eye syndrome), pannus, etc.
- Corneal lipid deposition that may be inherited (breed-related) or acquired as a result of chronic corneal disease, high fat/cholesterol levels in the body, or chronic hypothyroidism (low thyroid hormone levels)
- Corneal mineralization (calcium deposits) from chronic corneal disease or associated with chronic kidney disease or certain hormonal diseases, ulceration or metabolic disease
- Invasion of the cornea with tumor cells (rare)
- Invasion of the cornea with dark, pigmented cells secondary to dryness, exposure or inflammation
- Development of corneal edema associated with age or with premature degeneration of the cornea, from glaucoma, in association with inflammation of the interior of the eye, secondary to prior surgery of the cornea, etc.
Numerous changes in the front chamber and fluid of the eye may cause visible cloudiness:
- Cloudiness of the fluid in the front chamber from inflammation (uveitis), hemorrhage, trauma, or leakage of fatty material into the eye (from the blood stream)
- Movement of the lens into the front chamber, particularly if the lens has developed an opaque cataract or is causing corneal edema
- Collapse of the chamber with movement of the iris towards the front of the eye (secondary to penetrating trauma, lens movement, glaucoma, etc.)
- Growth of tumor from the iris into the front chamber
Changes of the lens that cause cloudiness in the eye include:
- Cataract formation
- Nuclear sclerosis. This is an age-related lens hardening resulting in an ‘opalescent’ color change to the lens
- Congenital defects in the blood vessels around the lens
Changes of the vitreous that may cause obvious clouding of the eye include:
- Congenital defects of the front portion of the vitreous
- Vitreal opacities (floaters) that accumulate with inflammation around or within vitreous
- Hemorrhage in to the vitreous
- Detachment and forward movement of an opaque retina into the front of the vitreous
It is essential that a specific cause be identified in order to initiate appropriate therapy. In general, opacities of the eye that develop suddenly, reduce vision, and/or cause pain (rubbing eye, squinting) are inherently more serious and necessitate immediate medical attention.
The following diagnostic tests are essential in helping to diagnose and treat your pet’s ocular disease:
- Complete medical history and physical examination
- Complete ophthalmic examination including slit-lamp biomicroscopy (magnified examination of the eyelids, cornea, front chamber of the eye and lens) and indirect ophthalmoscopy (magnified examination of the vitreous body and retina)
- Schirmer tear test to determine if tear production is normal, elevated or reduced
- Fluorescein and possible rose bengal staining of the cornea to detect surface defects, ulcers, and erosions
- Tonometry (measurement of the pressure within the eye) to evaluate for the presence of glaucoma
- Complete blood count (CBC) and serum tests to identify any related medical problems
Additional diagnostic tests may be recommended based on results of initial tests or due to a lack of response to prior treatments.
These tests may include:
- Corneal cytology (complete cell analysis) of cell samples collected from infected or inflamed corneas to determine the presence of infectious organisms and type of inflammatory reaction.
- Corneal culture of cells collected from corneal ulcers to identify the specific type of bacteria or fungi present and which antibiotics they are most susceptible to.
- Paracentesis (collection of a fluid sample from the anterior chamber or vitreous body obtained with a small needle) is an alternative for attaining a diagnosis of undefined uveitis (or cancer) utilizing cytology and serology.
- Serology (testing of antigen-antibody reactions in-vitro) when systemic fungal diseases (cryptococcosis, blastomycosis, coccidioidomycosis), toxoplasmosis (a protozoal disease)or tick-borne diseases are suspected.
- Gonioscopy (magnified examination of the fluid drainage angle within the eye using a specialized lens) to help classify the type of glaucoma present.
- Electroretinography (evaluates the electrical responses of the retina to light stimulation) to ensure that the retina is functioning normally.
- Ultrasound examination of the eye (imaging technique in which deep structures of the eye are visualized) when the eye is too opaque for normal examination procedures
Therapy is dependent upon the underlying cause.