Band keratopathy

Precipitation of calcium salts, subepithelial

Due to:

• hypercalcemia 2^ hyperparathyroidism, excessive vitamin D intake,
  renal failure, hypophosphatasia, milk-alkali syndrome, Paget disease,
  sarcoidosis
• topical medications that contain phosphates (steroid phosphates,
  pilocarpine)
• chronic ocular inflammation (uveitis, end stage glaucoma) causes elevation
  of the surface pH out of the physiologic range which changes the solubility
  product and favors precipitation
• compromised endothelial function and corneal edema (2^ silicone oil from RD surgery)

Lab studies:

• serum calcium and phosphate level
• if sarcoid is suspected, an angiotensin-converting enzyme (ACE) should be obtained
• parathyroid hormone levels