Degeneration of the Cornea in Dogs

Degeneration of the cornea occurs as the result of lipids being deposited within the eye, due either to an inherited trait or to an underlying disease. Corneal dystrophy is generally irreversible while corneal degeneration may potentially be helped by treating the underlying condition. In both cases, the deposit does not typically cause pain but may lead to eventual blindness.

Corneal degeneration and corneal dystrophy are similar conditions in which lipids build up within the eye, leading to a white deposit in the front of the eye. The former typically occurs as the result of trauma or an underlying disease, while the latter tends to be inherited. Both conditions have the ability to affect one or both eyes and may lead to other conditions, such as ulcers or blindness.

Corneal degeneration is characterized by a white, opaque deposit in the front of the dog's eye, either at the center of the eye or at the periphery. The deposit may vary in size and shape, and it may affect one or both eyes. Other possible symptoms include visual imparity or pain in the eye.

Types

Corneal degeneration and corneal dystrophy are two terms that may be used interchangeably but actually refer to two different conditions. Corneal degeneration often affects one eye and commonly occurs as the result of trauma or of another ocular disease. Corneal dystrophy has a similar appearance to corneal degeneration, but it is hereditary instead of acquired and is usually bilateral.

Corneal degeneration occurs when cholesterol or calcium is deposited in the cornea, resulting in a white shape in the eye. This typically is the result of trauma or chronic irritation due to a systemic or ocular disease and is commonly seen in geriatric dogs. High cholesterol, usually associated with hypothyroidism, may lead to an infiltration of the cornea.

Corneal dystrophy is an inherited disease that more often affects certain breeds, including the Shetland Sheepdog, Siberian Husky, Beagle, Cocker Spaniel, Airedale Terrier, and Boston Terrier. It is unknown how the trait is passed down though it appears to be linked to sex in the Airedale Terrier.

The veterinarian will conduct both a thorough physical examination and a complete eye exam, the latter of which may include several tests. The Schirmer Tear Test is used to measure tear production and helps determine the amount of lubrication the corneal surface receives, while application of the fluorescent dye, fluorescein, can reveal any physical breaks in the cornea. The veterinarian may also wish to examine the eye's interior in order to confirm any underlying ocular diseases.

Because corneal degeneration is often the result of another condition, further tests may need to be conducted so that the underlying cause can be properly addressed. This may include thyroid tests in cases where cholesterol levels are elevated or tests for kidney function.

Both corneal degeneration and dystrophy are not directly treated, as lipid development cannot be decreased with medication and surgery does not provide a permanent cure. If any underlying conditions are present with corneal degeneration, they will need to be addressed before any further steps are taken. Treatment of the underlying disease may result in a reduction of the lipid deposit.

Corneal dystrophy is not typically painful though it does result in discomfort or pain for certain dogs. If a dog is in pain because of the condition, or if his vision is impaired, the veterinarian will discuss possible treatment with you. Options are limited and focus more on managing symptoms than on treating the condition, as dystrophy is irreversible. Surgery may temporarily reduce the size of the deposit, and eye drops or cream may reduce tearing by keeping the cornea wet.

Recovery varies depending on the condition, as well as its cause. Follow any instructions given by the veterinarian, and administer the full course of any medications that are prescribed. Monitor your dog for signs of pain, and if any additional symptoms appear, speak to the veterinarian.

The veterinarian may require follow-up examinations to check for inflammation or ulceration in the eye. If your dog is being treated for an underlying condition, reexamination may be needed to monitor the effectiveness of the treatment.