Ectropion is an abnormal eversion (outward turning) of the lid margin away from the globe. Without normal lid globe apposition, corneal exposure, tearing, keratinization of the palpebral conjunctiva, and visual loss may result. Ectropion usually involves the lower lid and often has a component of horizontal lid laxity. Treatment is individualized based on the appropriate identification of the etiology.
Involutional ectropion – the most common form of ectropion, this is due to the increasing laxity of tissues associated with the normal ageing process. In this case both eyes are usually affected equally, or to similar extent.
Cicatricial ectropion – related to scarring (recall that cicatrix is the medical term for a scar), e.g. as a result of burns. In this case, either one or both eyes may be affected.
Mechanical ectropion – may be due to excess weight of the eye-lid itself, such as e.g. due to tumour.
Paralytic ectropion – associated with facial nerve palsy, this classification applies to ectropion resulting from damage to the facial nerve that supplies and controls the affected lower-eyelid. May involve incomplete closure of the affected eye-lid.
Congenital ectropion – that is, ectropion present since birth. May occur as part of blepharophimosis syndrome.