Lecture 4/5 2/4/25 and 2/6/25 Flashcards
What is pigmentary keratitis?
corneal changes that occur with chronic trauma/irritation that manifests as corneal pigmentation, vascularization, and scarring
What are the etiologies of pigmentary keratitis?
-keratoconjunctivitis sicca
-trichiasis/aberrant dermis
-nasal fold trichiasis
-pagoda lid/ectropion
-lagophthalmia
-entropion
-pannus
What is pannus?
immune-mediated, vascularized, pigmented lesion of the cornea
What are the etiologic factors of pannus?
-immune-mediated disease
-genetic factors
-UV radiation
Which breed is predisposed to pannus?
german shepherds
How is pannus diagnosed?
-appearance
-signalment
-lymphocytes and plasma cells on cytology
How is pannus treated?
-topical dexamethasone or prednisone
-cyclosporine or tacrolimus (maintenance)
-strontium radiation in severe cases
What are the possible differentials for white-looking corneal lesions?
-scars
-corneal/lipid dystrophy
-corneal/lipid/calcific degeneration
-corneal edema
-corneal stria
What do corneal scars result from?
-abnormal alignment of corneal stromal lamella
-secondary to ulceration or chronic disease
How are corneal scars diagnosed?
-grey irregular opacity appearance +/- vessels and pigment
-fluorescein negative
What is corneal/lipid dystrophy?
-primary, bilateral, inherited disorder of the cornea
-not accompanied by corneal inflammation of systemic disease
What is the etiology of corneal/lipid dystrophy?
-inherited condition of abnormal corneal metabolism
-most common in shetland sheepdogs, beagles, huskies
What is the appearance of corneal dystrophy?
-bilateral and symmetrical
-oval white/grey glittery refractile opacity
-no vessels
What is the treatment for corneal dystrophy?
-typically not indicated
-low fat diet may help
-potential for response to cyclosporine
-may improve with treatment for Cushing’s or hypothyroidism if disease is concurrent
What is corneal/lipid degeneration?
-deposition of lipid and/or calcium secondary to some other ocular disease
-can occur secondary to chronic topical steroid use
What is the appearance of lipid degeneration?
-white grey glittery appearance
-possible to have vessels and pigmentation
What is the treatment for lipid degeneration?
-typically not indicated
-low fat diet may help
-potential for response to cyclosporine
-may improve with treatment for Cushing’s or hypothyroidism if disease is concurrent
What are the characteristics of calcific keratopathy?
-deposition of mineral (calcium) in the cornea
-appears as short spicules of white, chalky looking material
-may be primary disease in geriatric dogs
What is the treatment for calcific keratopathy?
severe disease can be treated with topical EDTA in artificial tears; chelates calcium
What are the causes of corneal edema?
-glaucoma
-ulceration
-anterior uveitis
-endothelial dystrophy
-lens luxation
Which mechanisms typically prevent corneal edema?
-endothelial Na-K ATPase pumps
-corneal epithelium acting as a physical barrier; keeps tears out of stroma
What are the characteristics of endothelial dystrophy?
-progressive dysfunction of endothelial cells
-seen in middle to older age dogs
-results in axial or temporal focus of corneal edema; eventual progression to involve entire cornea
-can lead to formation of bullae/blisters within cornea
What are the characteristics of endothelial degeneration?
-can occur with anything that traumatizes, touches, or negatively affects corneal endothelium
-aging can be a cause due to loss of complement of endothelial cells
-endothelial cells cannot replace themselves because they are post-mitotic; cell loss can lead to edema in old age
What is the treatment for corneal edema?
NaCl ophthalmic ointment that reduces edema and prevents formation of bullae
What are corneal stria?
white/grey linear streaks that occur in Descemet’s membrane secondary to glaucoma
What are the etiologies of corneal masses?
-corneal neoplasia
-limbal melanoma
-dermoid
-epithelial inclusion cyst
-granulation tissue
-nodular granulomatous episclerokeratitis
Which type of corneal neoplasia is most common in dogs and cats?
squamous cell carcinoma (still VERY rare)
How is corneal neoplasia diagnosed?
-histopath of biopsy specimen
-cytology
What are the treatment options for corneal neoplasia?
-keratectomy
-strontium irradiation
-cryotherapy
What is limbal melanoma?
-darkly pigmented, infiltrative, benign tumor at the limbus
-typically located at dorsal limbus
-slightly elevated
-can be locally invasive, especially in younger dogs
What are the treatment options for limbal melanomas?
-watch mass/no action
-diode laser therapy or cryotherapy
-full thickness scleral graft
What is a dermoid?
congenital brown to pink mass on the cornea with hair growing from it
What is the treatment for dermoids?
keratectomy followed by medical treatment of the resulting ulcer
What are the characteristics of corneal granulation tissue?
-pink fleshy mass that occurs secondary to chronic injury
-treated by treating inciting cause +/- topical steroids
What is nodular granulomatous episclerokeratitis?
-idiopathic inflammatory swelling/mass at the limbus
-made up of fibroblasts, lymphocytes, macrophages, and potentially neutrophils and plasma cells
What is the treatment for nodular granulomatous episclerokeratitis?
-immunosuppressive strategies
-surgical excision/subtotal resection
