Layers of the Cornea
The cornea is the clear outer structure of the eye which is responsible for bending light into the eye. The cornea is composed of several layers. The top layer of the cornea is called the corneal epithelium, beneath it is Bowman’s membrane, then the corneal stroma, followed by Descemet’s membrane, and the final layer is the corneal endothelium.
Each layer has specific functions and purposes for ocular health. The largest layer is the corneal stroma which is responsible for the storage of nutrients and holding needed vitamins for the eye.
Cholesterol Buildup in the Eye
When there is excess cholesterol or fat in the body, the excess begins to be deposited into storage areas of the body.
One of these such areas is the corneal stroma. The stroma functions as a long-term storage option for these unnecessary fat compounds.
When these cholesterol and fat compounds begin to accumulate, the corneal stroma begins to show evidence of this type of buildup.
This ring of buildup is the beginning of the corneal arcus, and it will be viewable during a comprehensive eye examination.
Symptoms of Corneal Arcus
The only true symptom or sign of corneal arcus is the discoloration that forms as a ring in front of the iris.
This ring is the visualization of the cholesterol buildup in the corneal stroma.
While the ring of cholesterol is visible from the outside of the eye, it does not have any impact on the actual vision of the eye.
The corneal arcus does not alter the shape or function of the cornea in any way. Since it is only passively visible and does not impact the function or vision, it is rarely considered a concern.
When Corneal Arcus is a Concern
While corneal arcus itself does not pose any threat to vision or eye health, it can be indicative of a greater health issue.
Usually, corneal arcus will only form in the elderly population, specifically those over 65.
If corneal arcus develops in a much younger individual, it may be because cholesterol or other fat compound levels are extremely high or unstable.
The condition, called hypercholesteremia, is common in the American population but it must be very advanced in order to form corneal arcus.
If corneal arcus is found in these younger individuals, it warrants a complete blood panel and referral to the primary care provider.