Entropion is an inversion of the eyelid margin. When the lid turns inward, the eyelashes and skin rub against the eye creating a red, irritated eye sensitive to light and wind. If untreated, an ulcer may form on the cornea. It may be unilateral or bilateral and may be classified as; Congenital or Acquired. Acquired entropion may be spastic, involutional, or cicatricial in nature. Lower lid entropion (usually involutional) is much more common then upper lid entropion (usually cicatricial).
Congenital Entropion – is very rare. The etiology is felt to be a faulty development of the lower lid retractors (lid stabilizers) with overriding of the orbicularis oculi muscle. It will not improve spontaneously and requires surgical correction.
Acquired Entropion – involutional entropion is the commonest form of entropion and seen in the aging population. The pathophysiology is related to a loss of supportive structures in the lower lid. With age, the medial and lateral canthal tendons develop some laxity. The lower eyelid retractors also become thin and attenuated. As these processes occur, the tarsal plate begins to lose stability. With superior migration of the orbicularis, and active orbicularis tone the lid margin can be rolled in, resulting in entropion.
Acute Spastic Entropion – follows ocular irritation or inflammation. It is most frequently seen following intraocular surgery in a patient who has unrecognized or mild involutional lid changes preoperatively. The eye inflammation causes sustained squeezing or squinting of the lids which causes the lid margin to roll inward. Corneal irritation from the lashes causes further irritation and inflammation and perpetuates the problem.
Cicatricial Entropion – is a result of scarring on the conjunctival side of the lower lid. A variety of conditions may lead to this including cicatricial pemphigoid, infection, trachoma, herpes, thermal or chemical burns.
How is Entropion treated?
The treatment, for the most part, involves surgery. A temporizing measure which may correct the lid, in the short term, is taping the lid to evert the lid margin. Surgical tape or the sticky tape part of a bandaid, placed from the lower lid to cheek area, will evert the lid and relieve the corneal irritation from the lashes. In inflammatory entropion, this may occasionally be all that is needed. Once the inflammatory component settles, the lid may be fine. The treatment for entropion, in the majority of patients, is surgical. A variety of techniques exist. With the exception of children, they are done under local anaesthesia as an outpatinet. Dissolvable sutures are preferred and the lid heals in over the next few weeks.
Ectropion is an outward turning of the eyelid margin. Ectropion can cause dryness of the eyes, excessive tearing, redness and sensitivity to light and wind. It may be unilateral or bilateral and may be classified as congenital or acquired. Acquired ectropion may be involutional, paralytic, cicatricial, inflammatory or mechanical. Ectropion is much more common in the lower lid.
Congenital Ectropion – is very rare but may occur as a result of a vertical shortage of skin as seen in the blepharophimosis syndrome.
Acquired Ectropion – Involutional ectropion is by far the commonest form of ectropion. The etiology is similar to involutional entropion with laxity of the medial and lateral canthal tendons and attenuation of the lower lid retractors. The orbicularis muscle however does not ride upward. It has a normal or decreased tone. As a result of these involutional changes, the lid turns out. The ectropion may just involve the medial lid or it may involve the entire lid.
Paralytic ectropion – follows temporary or permanent seventh nerve palsy. The orbicularis loses its tone and the lid falls outward. Poor blinking and lid closure, lead to chronic eye irritation.
Cicatricial ectropion – involves a scarring process on the skin with resultant shortening. It may be seen secondary to thermal or chemical burns, trauma or from chronic inflammation associated with various dermatologic conditions such as rosacea, atopic dermatitis or excema.
Mechanical ectropion – is due to bulky tumors of the eyelid. Occasionaly, poorly fit glasses sitting on a lax lid will also pull it outward.
How is Ectropion treated?
Ectropion treatment for the most part is surgical. The only form that may be amenable to temporizing measures is the paralytic form secondary to 7th nerve palsy. In this instance, the use of lubricating drops and ointment combined with taping the lid closed at night may be successful in keeping the eye comfortable for a short while in anticipation of recovery of function.
Most ectropions, however, will require surgery. Surgery is generally done as an outpatient with local anaesthesia. The surgery involves tightening the lower lid and turning the lid margin back in to its normal position. It is very important to be on the lookout for a cicatricial process. If the patient has active skin disease causing tightening of the skin, this needs to be treated first. Once the skin is quiet, if the lid is still cicatricial, a skin graft or pedicle flap will be required. The best skin donor site is from the upper lid followed by the preauricular, postauricular and supra-clavicular regions.