Read the German translation: Erkankungen der Augenlider Beim Hund und Bei Der Katze
Lacerations of the lids which affect the lid margin should be treated surgically, as soon as possible, in order to reconstruct the lid margin. Otherwise scarring may lead to chronic conjunctival and corneal irritation. Careful and atraumatic tissue handling and minimal debridement are necessary to avoid necrosis. A figure-8-suture adapts the lid margin. The author´s preferred suture material is vicryl® 6-0 for the intramarginal adaptation and silk 6-0 for the cutaneous suture.
Distichia, Ectopic Cilia
Distichia are cilia emerging from the openings of the Meibomian glands. Few, soft, non-irritating distichia occur as an insignificant, coincidental finding in many dogs, especially in Cocker Spaniels, Boxers and Poodles. In certain breeds, like the Flat Coated Retriever, the Greater Swiss Mountain Dog, the Eurasian, the Chow Chow etc. they may be more bristly causing clinical signs like epiphora, blepharospasm and corneal ulceration. They can occur bilaterally and unilaterally, affecting upper as well as lower lids. In Shih Tzus, distichia occur in combination with an excessive accumulation of secretion within the meibomian glands.
Ectopic cilia also arise from the Meibomian glands, but emerge through the palpebral conjunctiva causing corneal irritation, oftentimes even ulceration. They can occur in any breed; however, the Flat Coated Retrievers and some brachycephalic dogs (Shih Tzu, Pug etc.) seem to have a higher incidence. The hereditary basis for distichia or cilia has not been established, although it seems probable due to the high incidence in some breeds. Breeding discretion is advised. Distichia and ectopic cilia are rare in cats.
If distichia or cilia cause irritation surgical therapy is indicated. Electro- and cryoepilation have been described, but the author's preferred technique for both conditions is surgical en bloc resection of the hair follicles from the palpebral conjunctival side.
Numerous dog breeds show conformational defects resulting in an inward-rolling of the lower and/or upper lids. Head conformation and structure, as well as weight and amount of the skin, also play an important role in this condition. Dolichocephalic dogs show mostly lower lid entropion, whereas Shar Peis may present with entropion of all four lids. Giant breeds (Great Dane, Bull Mastiff etc.) may show a combined lid deformation with entropion, ectropion and an overlong palpebral fissure. A polygenic inheritance is likely for lid conformational defects. Breeding should be towards head and periocular skin conformation that minimizes the likelihood of occurrence of lid deformations. Canine lower lid entropion may be secondary to chronic conjunctivitis which oftentimes turns out to be allergic. Other irritating causes may lead to spastic entropion.
In the older spaniels and some other breeds the skin of the forehead becomes flaccid leading to upper lid entropion.
In feline patients, entropion occurs as nasal entropion in brachycephalic breeds or as lower lid entropion secondary to chronic conjunctivitis. In old cats it occurs secondary to enophthalmos due to atrophy of the orbital fat.
Whenever lid deformation leads to irritation, surgical correction is necessary. Numerous variations of techniques have been described. In puppies, tacking alone might be successful. For adults, the author's preferred technique is Hotz Celsus with or without wedge resection of the temporal portion of the lid for lower lid entropion and a modified Stades technique for upper lid entropion. If the entropion is spastic, tacking with or without a corneal bandage lens may be used to alleviate the spasm while the underlying disorder (i.e., conjunctivitis, corneal ulcer etc.) is treated. In cases of entropion secondary to chronic conjunctivitis, further diagnostics (cytology, histopathology) are recommended.
In dolichocephalic dog breeds with loose periocular skin, the lower lid may droop, thereby exposing conjunctiva leading to chronic conjunctivitis. In some breeds (Basset Hound, Blood Hound etc.) this is considered as part of the breed standard. If chronic irritation is clinically noted, simple wedge resection of the temporal lower lids is indicated.
Large Palpebral Fissure with Medial Entropium of the Lower Lids and/or Trichiasis
In brachycephalic dog breeds, the palpebral fissure may be extremely wide. In combination with their oftentimes shallow orbits, exposure of the cornea can lead to chronic keratitis. In certain breeds (Shih Tzu, Lhasa Apso, Pekingese etc.), nasal trichiasis (facial hairs touching cornea and/or conjunctiva) adds to the chronic irritation. In the Pug this condition is often combined with nasal entropion of the lower lids. These factors along with tear film abnormalities aggravate the Pug's predisposition to pigmentary keratitis. Surgical correction is indicated in those conditions. A modified medial canthoplasty is extremely alleviating and has an excellent long-term effect in those patients. When performed early in life (ideally before one year of age) irreversible corneal changes may be prevented.
Inspissation of the secretory products of the Meibomian gland will cause swelling and inflammation of the gland and the surrounding tissue with or without bacterial infection. Drainage of the secretion through a conjunctival stab incision is combined with topical antibiotics and steroids and systemic NSAIDs. Warm compresses will increase the perfusion and thereby speed up the healing process.
Multiple Meibomian gland inflammation and infection with Staphylococci may cause swelling, pruritus, pain, secretion and conjunctivitis. Culture and sensitivity testing will reveal the causative bacteria and the antibiotic of choice. Topical antibiotic and steroid combinations as well as systemic antibiotics are required. Warm compresses are recommended. Systemic prednisone may be necessary if hypersensitivity to the bacterial antigens occur. A vaccination can also be applied. Protracted therapy is often essential to control the inflammation.
In older dogs, adenomas of the Meibomian glands occur frequently. The author recommends early v-shaped excision of the altered lid margin to avoid more invasive techniques with skin grafting when the tumor grows bigger. Other types of neoplasia also occur in the canine lids including melanoma, mast cell tumor, histiocytoma. Less common are highly malignant tumor types like sarcomas or carcinomas.
In contrast, lid neoplasias in the cat occur less frequently than in the dog. They are mostly malignant, among them squamous cell carcinoma, mast cell tumor and lymphoma. Biopsy should precede surgical excision as some of the tumor types are not treated surgically or require adjunctive therapy.
Feline Periocular Hydrocystadenomas
In elderly cats, especially in Persians, the formation of multiple periocular cysts is not uncommon. The cystic wall is thin and almost transparent. The cysts are filled with honey-colored viscous fluid. Cysts may also be present around the mouth. Intervention is only necessary if the cysts touch the cornea and cause irritation. Resection is usually not possible due to the extent of the cysts. Simple drainage of the cysts by puncturing them with a 20 gauge cannula is sufficient. They will refill over time and the drainage can be repeated. Cryotherapy after drainage has been anecdotally reported to be successful.