Introduction

• Inversion or inward rolling of the eyelid margin, such that hair-bearing skin can rub against cornea.
• Cause:
  • Primary entropion often breed related - probably inherited.
  • Secondary entropion may be caused by painful corneal conditions that result in enophthalmos or abnormal skin folds, eg older Cocker Spaniel English Cocker Spaniel , Chow Chow Chow Chow.
• Signs: corneal irritation, pigmentary keratitis, epiphora, keratitis Keratitis , and possible corneal ulceration Ulcerative keratitis.
• Treatment: several surgical techniques available.
• Prognosis: good.
  Print off the owner factsheet on Entropion Entropion to give to your client.

Pathogenesis

Predisposing factors

• Genetic predisposition in facial conformation and eyelid support.

Specific

• In brachycephalic breeds, tension on the medial canthal ligament, coupled with nasal folds and abnormal facial anatomy, results in rolling in of the medial canthus and the upper and lower eyelids medially.
• In giant breeds with heavy facial skin or excessive facial folds, laxity of the lateral canthal ligament causes upper lid, and lateral lower lid, entropion.
• In older Cocker Spaniels upper lid sagging causes entropion and trichiasis Trichiasis.

Pathophysiology

• Primary entropion - anatomical.
• Secondary entropion - alteration in anatomical confirmation due to secondary factor.

• Anatomical entropion → corneal irritation, keratitis Keratitis → corneal ulceration Ulcerative keratitis.

• Cicatrical: scarring of eyelid → entropion.
• Spastic: secondary to a painful corneal condition which results in retraction of the globe and muscular spasm in the orbicularis oculi muscle. This form can occur in all ages.
• Atonic: older individuals, especially English Cocker Spaniel . A loss of elasticity in the skin on the top of the head results in the palpebral fissures slipping down the face. The upper lid tends to roll inwards causing entropion/trichiasis, while the lower lid droops downwards (ectropion Ectropion ). These individuals are worse when tired or if the head is lowered.
• Secondary to facial folds: usually middle-aged Chow Chow (especially males) . Subdermal fat deposits in the folds of skin around the eyelids → 360° entropion .
• Seconday to weight loss: loss of orbital fat can result in entropion.

Timecourse

• Most cases of primary entropion present before 6 months of age. Occasionally, some cases present >12 months.
• Entropion in the Shar Pei can present as early as 2 weeks. It may be so severe that the breeder believes the pup's eyes have not yet opened.

Diagnosis

Treatment

Outcomes