What is corneal lipidosis?
Corneal lipidosis is an accumulation of fatty substances (usually cholesterol) within the layers of the cornea. (Image of healthy dog cornea at right.)
What causes corneal lipidosis?
There are three main causes of corneal lipidosis: corneal dystrophy, corneal degeneration, and elevated blood cholesterol levels.
Corneal dystrophy is an inherited (genetic) condition and is most seen in dogs. This condition is rarely seen in cats. It is usually present in both eyes. It is not painful and has a minimal effect on vision. Some commonly affected breeds include beagles, Cavalier King Charles spaniels, Siberian huskies, Alaskan malamutes, Samoyeds, American cocker spaniels, Labrador retrievers, and collies.
Corneal degeneration occurs secondary to inflammation in the eye and is usually associated with other eye diseases, such as anterior uveitis (inflammation of the iris, choroid, and ciliary body), keratitis (inflammation of the cornea), keratoconjunctivitis sicca (“dry eye”) or scleritis (inflammation of the sclera or white of the eye) Sometimes lipid accumulation is associated with trauma, such as after corneal ulceration that healed with lipid deposits. This is seen more frequently in dogs than cats.
Lastly, elevated cholesterol levels (hyperlipidemia) can cause corneal lipidosis. This may be due to underlying causes such as Cushing’s disease, long-term steroid use, diabetes, or hypothyroidism.
What are the clinical signs of corneal lipidosis?
Lipid deposits in the cornea appear as well-defined areas of sparkly, shiny, or crystalline material. When lipidosis is due to corneal degeneration, other clinical signs may include inflammatory indicators such as eye redness or cloudiness in the eye.
How is corneal lipidosis diagnosed?
It is diagnosed by a thorough eye exam (including fluorescein dye application and Schirmer tear test), bloodwork, and patient history, including age and breed. If your veterinarian suspects hyperlipidemia, then fasting cholesterol, triglyceride, and blood glucose level tests will be recommended.
How is corneal lipidosis treated?
Treatment for corneal lipidosis depends on the cause. Corneal dystrophy does not require treatment. Your veterinarian will monitor your pet’s eyes periodically to watch for the development of corneal ulcerations. Corneal degeneration requires treating the primary inflammatory condition in the eye, which may include antibiotics or anti-inflammatory eye drops. Your veterinarian may also prescribe pain medication or artificial tear ointment to provide lubrication to the eye and comfort if the corneal surface is irregular.
Lastly, any condition that is causing an elevated cholesterol level must be treated directly to reduce blood cholesterol levels. Dietary management, along with supplements to reduce cholesterol (flaxseed oil, oat bran, and niacin), can also be helpful in reducing cholesterol levels. “Statins” such as atorvastatin (Lipitor®) may also be prescribed.
If vision is affected or if corneal ulceration occurs multiple times, referral to a veterinary ophthalmologist is recommended.
What is the prognosis of corneal lipidosis?
Corneal dystrophy may resolve on its own and typically does not progress. It usually does not interfere with vision.
The prognosis for corneal degeneration depends on the underlying eye disease. It may progress with chronic inflammation and vision may be affected with advanced disease. Typically, corneal lipidosis does not progress after trauma.
If an underlying disease condition (Cushing’s disease, diabetes, or hypothyroidism) is identified and managed, the prognosis is good. Your veterinarian may recommend periodic blood tests to monitor cholesterol and triglyceride levels.
