What defines an ectropion?

An ectropion is defined as an abnormal eversion of the lid margin, which results in the eyelid turning outward away from the eyeball. This condition can cause various complications, including exposure of the conjunctiva and cornea, leading to irritation and an increased risk of dryness and infection.

In essence, the outward turning of the eyelid interrupts the normal protective function it provides for the eye, which can lead to symptoms such as tearing and discomfort. The other options presented describe different eyelid abnormalities or conditions that do not correspond to the specific etiology of ectropion. For instance, inward turning of the lid margin describes entropion, while swelling of the eyelid and infection of the conjunctiva refer to separate clinical manifestations.