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Perilimbal pocket technique for surgical repositioning of prolapsed nictitans gland in dogs

The Veterinary Record; London Vol. 171, Iss. 10,  (Sep 8, 2012): 247. DOI:10.1136/vr.100582

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Introduction

The canine nictitating membrane (membrana nictitans, third eyelid; NM) is a mobile fold of conjunctiva located in the nasal inferior fornix. Its base is supported by the superficial and middle muscular fasciae, and by smooth muscle fibres originating from the periorbita, which maintain it in a retracted position ( Constantinescu and McClure 1990 , Murphy and Pollock 1993 ). The tubuloacinar seromucoid gland wraps around the inferior portion of the T-shaped, hyaline cartilage, and contributes to up to 50 per cent of the aqueous part of the tear film ( Murphy and Pollock 1993 , Maggs 2008 ). Other functions include physical protection to the cornea, distribution of the tear film and immunological support (Schlegel and others 2003). Prolapse of the nictitating gland or 'cherry eye' is one of the most frequently encountered diseases of the canine NM. The prolapsed gland appears as a red mass partially or totally visible above the membrane's free margin between the cornea and NM ( Hendrix 2007 ). Although the exact pathogenesis remains uncertain, lymphoid hyperplasia and laxity of the connective tissue attachment between the NM and periorbita have been proposed as likely aetiological mechanisms ( Hendrix 2007 , Maggs 2008 ).

In a study of 89 cases, this disease was most common in the American cocker spaniel, English bulldog and Lhasa apso. In 59.5 per cent of dogs, the condition was unilateral, with the majority of cases occurring prior to one year of age (Morgan and others 1993). In a recent report of 114 dogs (155 eyes), 64 per cent were affected unilaterally. When the condition was bilateral, prolapse of the gland in the second eye occurred either simultaneously (41.4 per cent of bilateral cases) or in most dogs within three months (70.8 per cent of bilateral cases) (Mazzucchelli and others 2012)....