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Corneal Discoloration 205.e3

○ Corneal calcium deposition (dense, chalky
white)
VetBooks.ir ■ Systemic disease: hypercalcemia, hyper- Diseases and Disorders
Corneal degeneration
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phosphatemia, hyperadrenocorticism,
renal disease, hyperparathyroidism,
hypervitaminosis D, idiopathic
○ Mucopolysaccharide
Genetic disease (mucopolysaccharidosis)
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• White/yellow or white/pink discolorations
○ Inflammatory cell infiltration A B
Infected corneal ulcer
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Corneal abscess (infectious or sterile)
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○ Feline proliferative (eosinophilic) kerato-
conjunctivitis (plaques and infiltrates)
○ Corneal epithelial inclusion cyst
• Gray-blue discolorations
○ Corneal edema
Corneal endothelial loss or damage:
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endothelial dystrophy, uveitis, glau-
coma, trauma (anterior lens luxation
with endothelial contact, intraocular C D
surgery)
Corneal edema due to epithelial loss: CORNEAL DISCOLORATION Causes of discoloration. A, Chronic superficial keratitis with corneal vascularization
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corneal ulceration (black star), pigmentation (white star), and lipid deposition due to degeneration (arrow heads). B, Crystalline
Corneal edema associated with corneal opacity associated with perilimbal lipid keratopathy. C, Diffuse edema due to endothelial dystrophy. D, Deep
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vascularization corneal ulceration with inflammatory cell infiltration (arrows) and corneal vascularization (black star).
○ Florida keratopathy (see Etiology and
Pathophysiology, above)
• Red/pink discolorations
○ Corneal vascularization • Fluorescein staining: positive in corneal Acute and Chronic Treatment
Corneal injury or inflammation ulceration Treatment will vary depending on the underly-
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❏ Corneal ulceration • Tonometry: elevated intraocular pressure ing cause.
❏ Chemical irritation (>30 mm Hg) in glaucoma and reduced
❏ Mechanical irritation (trichiasis, (<10 mm Hg) in some cases of uveitis PROGNOSIS & OUTCOME
ectopic cilia)
❏ Exposure: large palpebral fissure, Advanced or Confirmatory Testing Prognosis and outcome vary depending on the
lagophthalmos (incomplete closure of • CBC, serum biochemistry profile, urinalysis, underlying cause.
the eyelids), ectropion, buphthalmos serum lipid profile (total serum lipids,
(chronic glaucoma), exophthalmos, cholesterol, triglycerides, lipoprotein PEARLS & CONSIDERATIONS
neuroparalytic keratitis (cranial nerve electrophoresis, ± cholesterol esters and
VII lesion) phospholipids), thyroid ± adrenal gland Comments
❏ Neurotrophic keratitis (cranial nerve testing are recommended if lipid or calcium In determining the underlying cause, docu-
V lesion) infiltration is suspected in association with mentation of location, color, shape, and pattern
❏ Keratoconjunctivitis sicca systemic disease. of corneal discoloration and presence of other
❏ Qualitative tear film abnormalities • Cytologic evaluation of conjunctival scraping concurrent ocular disease are extremely helpful.
❏ Chronic superficial keratitis (CSK/ or conjunctival biopsy is useful in diseases
pannus): dogs associated with conjunctival inflammation Technician Tips
❏ Proliferative keratoconjunctivitis: cats or proliferation. Digital photography of corneal lesions should
❏ Corneal degeneration • Cytologic evaluation of corneal scrapings is be used in monitoring progression and response
Adjacent ocular disease: uveitis, episcle- useful in proliferative disease of the cornea to therapy.
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ritis, scleritis, orbital disease, glaucoma or inflammatory cell infiltration of a corneal
ulcer. SUGGESTED READING
Initial Database Ledbetter EC, et al: Diseases and surgery of the canine
Complete ophthalmic examination is essential, TREATMENT cornea and sclera. In Gelatt KN, et al, editors:
including the following: Veterinary ophthalmology, ed 5, Ames, IA, 2013,
• Schirmer tear test: values < 10 mm/min are Treatment Overview Wiley-Blackwell, pp 976-1049.
consistent with KCS; values of 10-15 mm/ The goals of treatment are to halt progression, AUTHOR: Lynne S. Sandmeyer, DVM, DVSc, DACVO
min suggest KCS and should be interpreted treat the underlying cause, and reduce ocular EDITOR: Diane V. H. Hendrix, DVM, DACVO
in light of other clinical signs. discomfort.
• Tear film break-up time: values < 10 seconds
suggest a qualitative tear film abnormality.

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