by Noelle La Croix, DVM, Dip. ACVO
Eyelids protect the cornea from trauma, refresh the tear film, sweep away foreign debris, and block light during sleep. In mammals, the upper eyelid rises above the pupil allowing for vision and it reflexively closes (or blinks) to protect and lubricate the cornea. Trauma, neoplasia, and genetic disorders may necessitate the reconstruction of an animal eyelid.
A reconstructed eyelid consists of a minimum of 3 layers: superficial skin, intermediate muscle/fibrous tissue, and deep mucosa. The skin of the upper eyelid must be supple and elastic for mobility. Upper eyelid muscles are normally innervated by facial and ocular motor cranial nerves. Hairs covering eyelid skin must grow away from the eyelid margin to prevent trichiasis. The upper eyelid margins must be structurally supported by fibrous tissue to prevent inversion or eversion (Figure 1). A mucosal will prevent keratitis of the non-keratinized epithelium of the cornea.
A reconstructed lower eyelid does not require extensive mobility, although movement will facilitate tear drainage. Dogs and cats with functional upper eyelids will tolerate the loss of their lower eyelids. These animals will experience constant epiphora and irritation of exposed conjunctiva, but their eyes will remain healthy (Figure 2). However, the cornea will desiccate if even a small portion of the critical upper eyelid (particularly central defects) is lost.
In general, the best tissue to reconstruct an eyelid with is other eyelid tissue. Up to 1/3rd of the eyelid margin can be resected and directly closed due to the elasticity of this tissue. Usually, eyelid masses ≤ 4 mm in diameter (with 1-2 mm of healthy adjacent margins) can be easily resected and directly closed without complications. This “wedge resection” begins with a 4-sided en-bloc resection of the mass. This generates a house-shaped defect in an upper eyelid, or an inverted house-shaped defect in a lower eyelid (Figure 3). The eyelid is stabilized with a Chalazion clamp or Jaeger eyelid plate while incisions are made with a #15 Bard-Parker blade. Subconjunctival tissue is then closed with 5-0 or 6-0 absorbable sutures (Vicryl) in a mattress pattern. A figure-eight, or cruciate, suture of 5-0 Vicryl or silk closes the eyelid margin (Figure 4). The knot of this suture is placed externally, 3 to 4 mm from the eyelid margin to prevent irritation of the cornea. The remaining incision is closed with simple interrupted sutures of 5-0 Vicryl or silk. The patient should remain in an E-collar until suture removal 10 – 14 days later. Triple antibiotic ointment (neomycin-polymyxin B-bacitracin) is prescribed to prevent secondary infection.
Larger eyelid defects require more extensive reconstruction techniques by a veterinary ophthalmologist. Upper eyelid tissue can be replaced with lower eyelid tissue by the Mustardé or Cutler-Beard multi-stage procedures. Large lower eyelid defects can be replaced with adjacent cheek (“semi-circular cheek flap” or “H-figure plasty”) or upper lip tissue.
Most animals with properly reconstructed eyelids have minimal complications. In questionable cases, the choice of reconstructive technique is best made in consultation with a veterinary ophthalmologist.
Noelle La Croix, DVM, Dip. ACVO
Veterinary Medical Center of Long Island
75 Sunrise Highway
West Islip, New York 11795
(631) 587-0800; fax (631) 587-2006
Figure 1: Schematic sections of the upper eyelid showing how the skin will roll down under the eyelid margin in the absence of connections to the eyelid fibrosis layer.
Figure 2: A 3-year-old Poodle with chronic avulsion of the lower right eyelid. There is conjunctival irritation and epiphora, but the cornea is healthy.
Figure 3: A 10-year old Cocker Spaniel with upper and lower eyelid masses. The masses were removed via four-sided wedge resections outlined by the dashed lines.
Figure 4: Schematic representation of a cruciate, or figure-8, suture used to perfectly appose the eyelid margins.