Corneal Pigment Deposits
Various types of pigment and pigmented chemical compounds may deposit in corneal tissue, resulting in focal or diffuse opacities. Pigments that deposit in the corneal epithelium include melanin, alkapton (brown color, seen in alkaptonuria), iron, and amiodarone. Amiodarone can result in a clockwise whorl-like pattern of golden-brown or gray deposits in the inferior interpalpebral portion of the cornea, referred to as cornea verticillate. Blood staining of the cornea (Fig 6-15A) may complicate hyphema when intraocular pressure (IOP) is very high for a long duration; however, if the endothelium is compromised, blood staining can occur even at normal or low IOP. Histologically, red blood cells and their breakdown products (hemoglobin and hemosiderin) are observed in the corneal stroma (Fig 6-15B). The hemosiderin is found in the cytoplasm of keratocytes and may be demonstrated with iron stains such as Prussian blue (Fig 6-15C).
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.