October 12 is National Pet Obesity Awareness day, sponsored by the Association for Pet Obesity Prevention (APOP), which is dedicated to collecting data from veterinarians and pet owners regarding their pet’s weight, nutrition, obesity treatment strategies, and to understanding the consequences of excess weight in pets. As with humans, pet obesity in America has become an epidemic that threatens pet health and wellbeing, with around 55% of dogs and almost 60% of cats classified as overweight or obese. According to the APOP, obesity can shorten your pet’s life expectancy by up to two and a half years, and increase their risk for diabetes, arthritis, cancer, and other health problems, including some conditions that affect eye health.
At Veterinary Vision Center, we see several eye conditions in dogs that are caused by hyperlipidemia (i.e., excess fat in the blood). The fats, namely cholesterol and triglycerides, are necessary for healthy cell function, but too much can be harmful. While not directly causing hyperlipidemia, obesity is considered a risk factor. Let’s take a closer look at hyperlipidemia, and how this condition can affect your dog’s eyes.
What causes hyperlipidemia in dogs?
Some hyperlipidemia cases occur without an underlying cause and can be attributed to genetic factors that affect fat metabolism, which most often occur in miniature schnauzers, beagles, and Shetland sheepdogs. Underlying disease causes the vast majority of cases in other breeds, and a high-fat diet can also contribute in dogs predisposed to hyperlipidemia development. The most common causes are endocrine in nature, affecting the way the body mobilizes and uses dietary and stored fats. These conditions are often associated with obesity, as a cause or a secondary effect, and include:
- Diabetes mellitus (i.e., “sugar” diabetes)
- Hypothyroidism (i.e., low thyroid)
- Hyperadrenocorticism or Cushing’s syndrome (i.e., excess cortisol)
- Pancreatitis (i.e., pancreatic inflammation)
- Acromegaly (i.e., excess growth hormone)
Hyperlipidemia signs in dogs
In humans, the main concern with high cholesterol is fats being deposited on the inside of important arteries (i.e., atherosclerosis). Atherosclerosis typically doesn’t occur in dogs, but excess cholesterol can affect other body systems. Prolonged hyperlipidemia can cause gastrointestinal upsets, including vomiting, diarrhea, belly pain, or poor appetite, and potentially seizures and pancreatitis. Some dogs don’t show obvious signs, but your veterinarian may see the problem during an eye exam when excess cholesterol spills over from the blood and deposits into the eyes.
Fat-related eye conditions in dogs
The eye conditions most commonly seen as a result of hyperlipidemia include lipid keratopathy, lipemia retinalis, and lipid aqueous.
- Lipid keratopathy — This condition is caused by fat deposits in the cornea, the normally clear tissue covering the front of the eye, that can sometimes obstruct vision, and may cause irritation or small ulcers on the eye surface. The deposits typically cannot be removed, and may progress over time. Antibiotic or anti-inflammatory eye drops can help with secondary complications.
- Lipemia retinalis — Lipemia retinalis describes the abnormal appearance of blood vessels in the retina, the tissue lining the inside back of the eye. Because of excess fat in the blood, the vessels appear swollen and pink or milky-white. Diagnosing this condition alerts your veterinarian to investigate and treat the underlying causes.
- Lipid aqueous — Aqueous humor is the clear fluid in the front portion (i.e., the anterior chamber) of the eye. Normally, only small molecules can pass from the blood into the aqueous humor, but if inflammation causes a barrier breakdown, large fat particles can pass through. Lipid aqueous presents as an acutely red and cloudy-white eye and is treated with anti-inflammatories and strategies to lower cholesterol.
Treating hyperlipidemia in dogs
High cholesterol or triglycerides treatment depends on the underlying cause. A low fat, high-fiber diet, along with cholesterol-lowering supplements or prescription medications, is effective for some dogs. If the underlying cause is known, treatment of the primary condition should help control cholesterol levels.
Maintaining your dog at a healthy weight is also important for reducing the risk of metabolic diseases that can lead to hyperlipidemia. Avoid feeding overly fatty treats that your dog does not usually eat, because this can cause a rapid rise in blood lipids that may lead to acute pancreatitis or lipid aqueous. Consider a low fat diet to prevent future issues if your dog is a high-risk breed.
To learn more about pet obesity, talk to your veterinarian or visit the APOP website. If you have questions or concerns about your dog’s eye health and how that can be affected by obesity and hyperlipidemia, contact us to schedule a visit with our Veterinary Vision Center team.
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