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Conformational Abnormalities |  |
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Entropion is an inversion of all or part of the lid margins that may involve one or both eyelids and the canthi. It is the most frequent inherited eyelid defect in many canine and ovine breeds, and may also follow cicatrix formation, and severe blepharospasm due to ocular or periocular pain. Inversion of the cilia (or eyelashes) or facial hairs causes further discomfort, conjunctival and corneal irritation, and if protracted, corneal scarring, pigmentation, and possibly
ulceration. Early spastic entropion may be reversed if the inciting cause is removed, or if pain is alleviated by everting the lid hairs away from the eye with mattress sutures in the lid, by subcutaneous injections (eg, of procaine penicillin) into the lid adjacent to the entropion, or by palpebral nerve blocks. Established entropion may require surgical correction.
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Ectropion is a slack, everted lid margin, usually with a large palpebral fissure. It is a common bilateral conformational abnormality in a number of dog breeds, including the Bloodhound, Bull Mastiff, Great Dane, Newfoundland, St. Bernard, and several Spaniel breeds. Contracting scars in the lid or facial nerve paralysis may produce unilateral ectropion in any species. Conjunctival exposure to environmental irritants and secondary bacterial infection can result in
chronic or recurrent conjunctivitis. Topical antibiotic-corticosteroid preparations may temporarily control intermittent infections, but surgical lid-shortening procedures are often indicated. Mild cases can be controlled by repeated, periodic lavage with mild decongestant solutions. |
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Lagophthalmos is an inability to fully close the lids and protect the cornea from drying and trauma. It may result from extremely shallow orbits (in brachycephalic breeds), exophthalmia due to a space-occupying orbital lesion, or facial nerve paralysis. Corneal scarring, pigmentation, and ulceration usually result. Unless the cause can be corrected, the therapy is frequent topical lubrication and surgical shortening or closure of the canthi either temporarily or
permanently. Excessive nasal skin folds and facial hair may aggravate the damage caused by lagophthalmos. |
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Abnormalities of the cilia include extra (distichia) or misdirected eyelashes on the lid margin. Epiphora, corneal vascularization, and corneal ulceration and scarring may result. In many instances, anomalous cilia are very fine and result in neither clinical signs nor damage. However, ectopic cilia protruding through the dorsal palpebral conjunctiva can cause profound pain. If the corneal or conjunctival damage is caused by the extra
cilia, excision or cryothermy of the cilia follicles is indicated. Anomalies of the cilia are common in some dog breeds and probably inherited. |
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