Entropion is a common external eye disorder. It can occur at all ages and manifests as an inward rolling of the lid margin of the eyelid. Depending on the severity of the lesion, it can cause some or all of the eyelashes to fall inward and touch the cornea, causing discomfort, and can occur in both the upper and lower eyelids. There are several ways to classify entropion, and depending on the age, it can be classified as congenital entropion or senile entropion. Regardless of the type of entropion, the clinical presentation is basically similar. In terms of symptoms, the main manifestations are irritation caused by inward contact of the eyelashes with the cornea, such as pain, photophobia, tearing, and foreign body sensation. In terms of signs, the main manifestations are conjunctival congestion, clouding of the cornea in spots or flakes due to eyelash irritation, and, when combined with inflammation, increased secretions. There are several causes of entropion, including scarring, spastic, and congenital entropion, with spastic entropion also referred to as senile entropion. Scarring entropion is often caused by trauma and chronic inflammatory diseases of the eye; spastic entropion is often caused by spasm of the orbicularis oculi muscle and is most commonly seen in the elderly; congenital entropion is most often associated with structural dysplasia of the eyelid.