My Dog’s Eyes Seem Cloudy - Is She in Pain?
Changes within the eye can interfere with vision and can sometimes be painful; early detection of changes in vision may allow reversal or preservation of vision if swift action is taken. Read on to learn about 5 common causes & outward symptoms of vision loss your dogs may face as they age.
Nuclear Sclerosis
QUICK DESCRIPTION: both eyes appear hazy in the center; diminished vision up close, but otherwise the dog sees well. Non-painful. Dogs over the age of 6 years old begin to develop nuclear sclerosis as a normal age related change of the lens. Loss of visual acuity at close distances (like missing the treat when you toss it) is the most common vision change. Long distance vision does not seem to alter significantly. No medications or treatments are indicated for nuclear sclerosis; it is important to differentiate this normal lens change from other causes of eye haziness.
Glaucoma
QUICK DESCRIPTION: eyeball is enlarged in size, appears hazy or blue diffusely, and vision is diminished. Depending on the cause, one or both eyes may be effected. Painful. An increase in fluid within the eyeball due to ineffective normal drainage results in increased pressure within the eye- similar to a clogged drain in a sink. Vision loss occurs due to increased pressure on the retina and optic nerve located in the rear of the eye. Vision loss may be reversible if patients are treated early and aggressively. Treatment is geared toward reducing eye pressure with medicated eye drops and IV medications. Chronic enlarged eyes that do not respond to medicine may be removed surgically for pet comfort.
Cataracts
QUICK DESCRIPTION: non-transparent whitening of part or all of the lens. Can be painful. Cataracts occur due to breakdown or weakness of fibers within the lens. Once formed, cataracts cannot be resolved with medication; surgical removal of the lens is the only treatment. Not all pets are good candidates for cataract surgery. An immature cataract still allows some vision, while pets with a mature cataract are blind in that eye. Unfortunately, glaucoma is a common secondary problem of mature cataracts. Eyes with cataracts would benefit from routine measurements of eye pressure to detect the earliest stages of increased eye pressure. Cataracts are either genetically inherited or acquired. Genetics are to blame as the most common cause dogs develop cataracts, with diabetes the second most common cause.
Ocular Masses
QUICK DESCRIPTION: symptoms vary based on location and type of mass and may include changes in eye color, visible masses on or within the eye, altered eyeball shape, or abnormal position of the eye. Vision may or may not be affected. Can be painful. Masses can grow within the eye tissue itself, or can invade the eye socket space from areas adjacent to the eye (brain, nasal cavity, oral cavity, etc). Purebred dogs appear more likely than mixed breeds to develop tumors. Tissue samples may be collected to determine the cause of the mass; in many cases eye removal is recommended. Location and type of tumor will determine treatment options; unfortunately some eye tumors in dogs are malignant and aggressive despite surgery or cancer treatments.
Retinal Degeneration
QUICK DESCRIPTION: clear eyes with dilated pupils and poor vision in dim lighting. Very progressive vision loss in both eyes is common. Non-painful. The retina is a tissue located in the back of the eye that receives light/sensory input and relays information to the optic nerve. When the retina is damaged, information does not transmit to the brain to form vision. Symptoms of retinal degeneration can occur very suddenly or may progress slowly over time. The primary cause is genetics, but some cases are idiopathic (cause undetermined). Increased reflectivity of the eyes at night is also a noted change that may occurs in the weeks following loss of vision. In most cases, vision is permanently lost with minimal treatment options known to be effective. Females are more commonly diagnosed with this disease.
Changes in vision or eye appearance should prompt an immediate visit to your veterinarian. An overall exam in addition to an ophthalmologic exam are needed to help diagnose the cause of vision loss. Additional imaging, lab work, and the expertise of a veterinary ophthalmologist may be recommended. Not all causes of vision loss are described here. Friendly reminder: Do not breed dogs with genetic diseases (including ocular disease) as this potentiates disease to future generations. In some dogs, more than one ocular disease process is present within the eye which can complicate diagnosis and treatment.
### Amanda Burow, D.V.M. (Dr. B), is a graduate of Iowa State University’s College of Veterinary Medicine. Dr. Burow’s patient list includes hunting dogs of all varieties, as well as several field trial dogs and full time sporting guide dogs. In addition to practicing general veterinary medicine, she has special interest in the areas of preventive care, emergency medicine, and dermatology. In her spare time, she enjoys being outdoors and on the lake, staying active, reading, and spending time with family and friends. Mud River is proud to share these tips from Dr. B with our customers. Keep in mind it is best to work with your local veterinarian to determine the needs for your animals.
