What are the two most common causes of corneal edema?

The two most common causes of corneal edema are indeed due to disruptions in the epithelial and endothelial barriers of the cornea. The cornea is a transparent structure that relies on the integrity of both its epithelial layer and its endothelial layer to maintain its clarity by regulating fluid content.

When the epithelial barrier is disrupted, it can lead to changes in fluid dynamics, causing the cornea to retain excess water, resulting in edema. Endothelial barrier disruption is particularly crucial because the endothelium is responsible for actively pumping excess fluid out of the cornea. If the endothelial cells become damaged or dysfunctional, their ability to maintain corneal dehydration is compromised, leading to swelling and opacity.

Conditions such as glaucoma, cataracts, or certain systemic diseases can cause endothelial dysfunction, while trauma or infections can lead to epithelial disruption. Understanding these mechanisms is key in veterinary ophthalmology, as managing corneal edema often involves addressing the underlying cause of barrier disruption.