Stromal and Descemet Membrane Pigmentation
Chlorpromazine, a member of the phenothiazine family, may cause corneal pigmentation in up to a third of patients on long-term chlorpromazine therapy. It probably enters the cornea through the aqueous; therefore, the brown opacities are first found in the posterior stroma, Descemet membrane, and endothelium. The drug later spreads to the anterior stroma and epithelium. Chlorpromazine can also deposit on the anterior lens capsule. Clofazimine may produce anterior stromal opacities or crystalline deposits. Isotretinoin is typically associated with fine, diffuse, gray deposits in the central and peripheral cornea.
Certain classes of metallic compounds can produce characteristic deep stromal or Descemet opacities. Long-term use of silver compounds, which were commonly used in the preantibiotic era to treat external infections, can result in a condition known as argyriasis, a potentially permanent slate-gray or silver discoloration of the bulbar and palpebral conjunctiva. Silver nitrate, which is applied to the bulbar conjunctiva in the treatment of superior limbic keratoconjunctivitis, can also cause argyriasis if this compound is applied excessively. Gold salts are one of the drugs that can be used in the treatment of rheumatoid arthritis. With long-term usage and cumulative doses exceeding 1 g, posterior stromal deposits that spare the Descemet membrane and corneal endothelium develop in a high percentage of patients. See Table 6-3 for a list of corneal deposits that may be of diagnostic importance.
Palay DA. Corneal deposits. In: Mannis MJ, Holland EJ, eds. Cornea. Vol 1. 4th ed. Philadelphia: Elsevier; 2017:251–264.
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.