Corneal Edema //
The cornea is a clear layer of tissue that covers the front of the eye in a way that is comparable to the clear crystal of a watch. Corneal clarity and smoothness are extremely important in allowing light to be focused into the back of the eye and onto the retina ("film" of the eye). The cornea has a tendency to absorb fluid from inside the eye in a way similar to a sponge. When it does this, the cornea swells and becomes cloudy like a piece of frosted glass. This natural affinity is offset by the presence of specialized "pumping cells" on the inner surface (endothelium) of the cornea that are responsible for removing this fluid and keeping the cornea clear.
Temporary or permanent dysfunction of the "pumping cell" layer is most frequently associated with aging, intraocular inflammation, elevated intraocular pressure, trauma and hereditary conditions (Fuchs' Dystrophy). As fluid accumulates in the cornea, progressive clouding of vision and increasing sensitivity to light develops. Discomfort may take the form of a mild foreign body sensation due to the formation of tiny surface blisters or intense, deep-seated pain if the blisters combine to form balloon-like blebs (bubbles).
Some of these problems (i.e, intraocular inflammation and elevated intraocular pressure) respond well to medical treatment with a return of normal or near normal pumping cell function. Others (i.e., trauma and hereditary conditions) tend to undergo progressive deterioration with increasing corneal swelling despite medical treatment with specially formulated salt drops. Management is often dictated by ones overall functional status, with the majority of patients ultimately requiring surgical replacement of the corneal pumping cells (corneal transplantation) in order to obtain comfort and improvement in vision.