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Corneal Pigmentation 207

• Ophthalmic exam (p. 1137): evaluate for
abnormalities of eyelids and aberrant cilia,
VetBooks.ir ○ Schirmer tear test (STT): values < 10 mm/ Diseases and Disorders
iris abnormalities, uveal cysts.
min and clinical signs consistent with
keratoconjunctivitis
○ Fluorescein staining: positive if corneal
ulceration is present. Fluorescein uptake
usually occurs only around the edge of a
A B corneal sequestrum.
○ Tonometry: elevated intraocular pressure
(>25 mm Hg) in glaucoma (can rise with
uveal melanoma/melanocytoma and uveal
cysts)
TREATMENT
Treatment Overview
The goals of treatment are to address the
underlying cause, halt progression, reduce
pigmentation, and reduce ocular discomfort.
C D
Acute and Chronic Treatment
CORNEAL PIGMENTATION Causes of corneal pigmentation. A, Pigmentary keratitis in a pug dog. B, Treatment will vary depending on the underly-
Chronic superficial keratitis (pannus) in a German shepherd dog. C, Corneal sequestrum in a Persian cat. D, ing cause.
Endothelial pigmentation in a mixed-breed dog.
Recommended Monitoring
Recheck at regular intervals (every 4-6 months
or more frequently depending on the cause).
to corneal ulceration, degeneration, or ○ Exposure keratitis: buphthalmos (chronic
corneal antigen. glaucoma), neuroparalytic keratitis (cranial PROGNOSIS & OUTCOME
• Endothelial pigmentation nerve VII lesion)
○ Adherence of melanin or melanin- ○ Keratoconjunctivitis sicca (KCS) (p. 568) Prognosis and outcome vary, depending on the
containing cells, usually arising from the ○ Pannus (chronic superficial keratitis) (p. underlying cause.
anterior uvea, to the endothelium 748): dogs
• Stromal infiltration at the limbus as extension ○ Limbal melanocytoma (NOTE: Mela- PEARLS & CONSIDERATIONS
of a melanin-containing neoplasm nomas of the limbus in dogs and cats
• Protrusion of pigmented iris through a are almost always benign and therefore Comments
corneal defect (p. 209) are appropriately called melanocytomas Ocular examination is an essential part of the
• Corneal sequestrum (p. 208): [p. 559]) routine physical examination because corneal
○ Associated with chronic irritation ○ Invasive anterior uveal melanoma/ pigmentation may go unnoticed by owners
○ The central/paracentral corneal stroma melanocytoma until it is so extensive it compromises vision.
becomes necrotic, brown-stained, and the ○ Protrusion of iris tissue through corneal
overlying epithelium is usually disrupted. defect (i.e., iris prolapse [p. 209]) Technician Tips
○ Corneal sequestrum (cats): brown foreign Digital photography aids in monitoring progres-
DIAGNOSIS material (p. 208) sion of lesions and response to therapy.
○ Dermoid: congenital presence of abnormal
Diagnostic Overview epithelial tissue SUGGESTED READING
The diagnosis is apparent on physical exami- • Endothelial pigmentation: persistent pupil- Morreale RJ: Corneal diagnostic procedures. Clin
nation. Species and breed are also important lary membrane (iris to cornea), anterior Tech Small Anim Pract 18:145-151, 2003.
considerations. synechia, uveal melanoma/melanocytoma,
rupture of pigmented uveal cyst [p. 1023]) AUTHOR: Lynne S. Sandmeyer, DVM, DVSc, DACVO
Differential Diagnosis EDITOR: Diane V. H. Hendrix, DVM, DACVO
• Epithelial and stromal pigmentation Initial Database
○ Pigmentary keratitis: large palpebral • Neuro-ophthalmic exam (p. 1136): evaluate
fissure, lagophthalmos (incomplete closure palpebral reflexes and completeness of eyelid
of the eyelids), trichiasis (entropion, nasal closure.
folds, aberrant dermis at medial canthus)

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