Corneal Mineralization in Dogs
Canine corneal calcification can present as a primary problem or may be the result of corneal degeneration or systemic diseases (hypercalcemia, hyperphosphatemia, uremia, hyperadrenocorticism). Although corneal dystrophy is usually bilateral, corneal degeneration can be unilateral. In addition, corneal mineralization can occur with many inflammatory ocular diseases. A total of 14 cases were evaluated from 2005 to 2008: 3 cases for cataract surgery and 11 for assessment of corneal lesions (due to hyperadrenocorticism, diabetes mellitus, and hepatopathy). Ocular disease was managed medically in 6 dogs and surgically in 6. Two dogs were not treated. Seven dogs had bilaterally symmetric lesions and 5 had unilateral lesions. Enucleation procedures had been previously performed in 2 dogs because of corneal abnormality. A total of 21 eyes with corneal calcification were evaluated. Sixteen (76.2%) demonstrated corneal ulceration (descemetoceles, corneal perforation, stromal ulceration, superficial punctate ulceration). Corneal lesions were distributed in an axial (central) or subaxial (subcentral, typically the ventral medial quadrant) location. In addition, many of the dogs had additional ocular abnormality. Hyperadrenocorticism was clinically suspected in 11 cases but confirmed in only 2. Keratectomy and histopathologic testing were performed in 3 cases and demonstrated calcium deposition. Other changes included edematous mineral deposits, loss of lamellar arrangement, epithelial focal hyperplasia, and separation of epithelium from underlying stroma.
Commentary: Corneal calcification is an uncommon clinical problem, but its potential devastating corneal and ocular clinical sequelae can result in eye loss. Therefore, clinicians must promptly address this condition and urge specialty referral if necessary to more accurately characterize it. In addition, such changes may be a harbinger for underlying systemic and additional ocular abnormalities, such as hyperadrenocorticism, and must be promptly addressed.
Calcareous degeneration of the canine cornea. Sansom J, Blunden T. VET OPHTHALMOL 13:238-243, 2010.