Band Keratopathy

Updated: Mar 03, 2016
  • Author: Michael Taravella, MD; Chief Editor: John D Sheppard, Jr, MD, MMSc  more...
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Overview

Background

Band keratopathy is characterized by the appearance of an opaque white band of variable density across the central cornea, formed by the precipitation of calcium salts on the corneal surface (directly under the epithelium). [1] This form of corneal degeneration can result from a variety of causes, either systemic or local, with visual acuity decreasing in proportion to the intensity of the deposition (see the image below). (See Etiology.)

Band keratopathy. Note the bandlike whitish-grey l Band keratopathy. Note the bandlike whitish-grey lesion across the central corneal surface, most prominent on the exposure surfaces, sparing the superior and inferior cornea, and gaps representing corneal nerves passing through the Bowman membrane.

Superficial debridement generally at least partially restores vision and comfort for most patients with band keratopathy, although failure to manage the source of the condition often leads to recurrence. (See Prognosis, Treatment, and Medication.)

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Etiology

Corneal deposition of calcium salt

Serum and normal body fluids (eg, tears, aqueous humor) contain calcium and phosphate in concentrations that approach their solubility product. Evaporation of tears tends to concentrate solutes and to increase the tonicity of tears; this is especially true in the intrapalpebral area, where the greatest exposure of the corneal surface to ambient air occurs. Elevated serum calcium or serum phosphate can tip the balance in favor of precipitation.

In addition, elevation of the surface pH out of the physiologic range changes the solubility product and favors precipitation. This type of tissue pH change can be seen in chronically inflamed eyes and may explain, in part, why patients of all ages with uveitis are at risk for the development of band keratopathy. [2, 3, 4]

Endothelial function may also play a role in calcium deposition. Compromise of endothelial function and corneal edema are sometimes seen in patients who have silicone oil inside the eye, when the oil comes into contact with the posterior cornea. The exact reasons for this association remain uncertain. [5, 6]

Band keratopathy was one of the main long-term complications (8% of patients) in a study of 50 ophthalmologic patients treated with silicone oil in whom the oil remained inside the eye for an unusually long period of time (median, 30 months). [7]

Systemic risk factors

The following conditions are associated with hypercalcemia, a risk factor for band keratopathy:

  • Hyperparathyroidism
  • Excessive vitamin D intake
  • Renal failure [8]
  • Hypophosphatasia
  • Paget disease
  • Sarcoidosis

Discoid lupus erythematosus and tuberous sclerosis are other systemic conditions associated with band keratopathy.

Local ocular risk factors

Local ocular conditions associated with band keratopathy include the following:

Chemically associated risk factors

Drug-associated calcium deposition can result from the following:

  • Steroid phosphate preparations (see the images below) [10]
  • Pilocarpine-containing, mercury-based preservatives
  • Viscoelastic agents - Rare, early formulations; may be related to phosphate buffers
  • Silicone oil
  • Topical medications containing phosphate buffers - Especially in the setting of chemical eye burns [11]
  • Intraocular use of tissue plasminogen activator [12]
    Calcium deposition associated with the use of dexa Calcium deposition associated with the use of dexamethasone phosphate. The calcium plaques appear as elevated white lesions at the edge of a persistent epithelial defect.
    The image shown is of a patient who developed a ca The image shown is of a patient who developed a calcium plaque following a corneal transplant and the use of a topical steroid phosphate preparation.

Chemical fume ̶ related risk factors include the following:

  • Mercury vapor
  • Calcium bichromate vapor
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Prognosis

Patients with band keratopathy may experience a decrease in vision as the deposition progresses across the visual axis. A foreign body sensation and irritation associated with an irregular surface are common symptoms. The ocular discomfort may worsen to the point of becoming disabling, especially as smaller segments of the plaque loosen and become partially mobile. The plaque itself often is visible and of cosmetic concern to the patient and family members.

As previously mentioned, unless underlying conditions have been addressed, removing the calcium deposits in band keratopathy will be associated with a high incidence of recurrence. In general, however, superficial debridement or lamellar keratectomy restores vision and comfort for most patients with band keratopathy, with the incidence of adverse outcomes following this procedure being very low.

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