Why is my older dog's eye blue? Is It Corneal Endothelial Degeneration?
What is Corneal Endothelial Degeneration?
Corneal Endothelial Degeneration (CED) is a condition that occurs in older dogs and affects the clarity of the cornea. This disease is a result of older age and can result in blindness and ocular discomfort. The cornea is the clear window at the front of the eye. It is a very thin, delicate structure with four layers. Endothelial cells are located at the innermost
layer of the cornea and contain “pumps” that are responsible for maintaining the fluid balance in the cornea. These pumps are critical to ensuring that the cornea remains relatively dehydrated and clear. There is an age-related decline in corneal endothelial cells which leads to corneal endothelial degeneration in some dogs. How is Corneal Endothelial Degeneration Diagnosed?
The condition can be diagnosed with a full ophthalmic examination. When corneal endothelial cells deteriorate and are no longer optimally functional, the normally clear cornea becomes “water-logged” and opaque with a foggy, blue appearance. This clinical finding is termed corneal edema. As the edema progresses, fluid-filled blisters, called bullae, can form on the cornea. These bullae can rupture resulting in corneal ulcers, which cause ocular discomfort. Once corneal edema begins to form, it typically progresses with time and cannot be completely reserved. How is Corneal Endothelial Degeneration Treated?
Treatment options for CED are limited. Palliative medical treatments, such as topical hypertonic saline, are used to stabilize the corneal edema and decrease corneal bullae formation. The high saline content draws fluid out of the
cornea. Medical treatment typically does not clear corneal cloudiness, but it is used to lower the risk of corneal ulcer formation. Surgical options for treatment of CED include corneal transplant, corneal grafting or flap placement, and thermokeratoplasty. Early diagnosis and early medical or surgical intervention can help your dog avoid ocular discomfort and slow or reverse vision loss. At The Animal Eye Institute, we use a combination of medical and surgical management with the use of hypertonic saline and the placement of a Gundersen conjunctival graft. These grafts also help to draw fluid out of the cornea as they contain an abundant blood supply.
What is the prognosis for Corneal Endothelial Degeneration? This is a life-long condition with good prognosis for comfort. The prognosis for vision depends on the severity of the corneal edema. The majority of dogs are well-managed with medication or surgery to reduce corneal ulcer formation and maintain their comfort level.
Patient treated with a Gundersen conjunctival graft to reduce the progression of corneal endothelial degeneration.
Same patient treated with a Gundersen conjunctival graft to reduce the progression of corneal endothelia. degeneration. These grafts maintain vision in these patients.