Everted Cartilage of the Nictitans Membrana
Occasionally the third eyelid in dogs will fold over on itself, causing an eversion. Great Danes, Golden Retrievers and Saint Bernards appear to have inherited traits for this condition, however, ill breeds can be affected. The third eyelid contains a cartilage support structure that may be defective or injured, thus allowing the folding to occur. When this happens the entire third eyelid will actually appear folded forward over on itself. Occasionally the cornea can become irritated and an eye discharge may then be apparent.
What are the risks? An everted third eyelid poses no great threat to health, except in rare instances where corneal irritation or infection develops. For both cosmetic and health reasons, most veterinarians recommend correction.
What is the management? Eversion is corrected by surgery. The defective cartilage within the third eyelid is dissected and removed, allowing the lid to unfold and return to its normal position.