2020–2021 BCSC Basic and Clinical Science Course™
8 External Disease and Cornea
Chapter 8: Systemic Disorders With Corneal and Other Anterior Segment Manifestations
Parathyroid hormone and calcitonin (one of the hormones produced by the thyroid gland) play key roles in regulating the amount of calcium in the blood and within the bones.
Primary hyperparathyroidism is most commonly associated with benign proliferation of chief cells within a single parathyroid gland and, in rare cases, with MEN. Secondary hyperparathyroidism can be caused by renal disease in which excessive amounts of calcium are lost and the glands release a compensatory amount of parathyroid hormone. Parathyroid hyperplasia can occur in the presence of hypercalcemia and hypophosphatemia associated with milk-alkali syndrome, sarcoidosis, and excessive intake of vitamin D. Calcium deposition can occur despite normal parathyroid function and normal levels of systemic serum calcium. See Chapter 6 for further discussion.
Table 8-7 Conditions Associated With Prominent Corneal Nerves
Figure 8-16 Prominent corneal nerves.
(Courtesy of Robert W. Weisenthal, MD.)
Calcium deposits within the interpalpebral area of the cornea are known as band keratopathy. The calcium is deposited in the superficial layers of the cornea and the Bowman layer.
If symptomatic with decreased vision or discomfort, the calcium can be removed with EDTA.
Darvish-Zargar M, Bartow RM. Endocrine disease and the cornea. In: Mannis MJ, Holland EJ, eds. Cornea. Vol 1. 4th ed. Philadelphia: Elsevier; 2017:696–704.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.