Histopathology of Chloroquine Retinal Toxicity

In the 1940's chloroquine and related antimalarials were subjected to extensive pharmacologic and clinical investigations.¹⁻⁶However, the dosage of chloroquine required to treat an acute attack of malaria or for prolonged suppressive therapy was small in comparison to the accumulated chloroquine dose attained in patients in the past decade in the treatment of chronic diseases such as rheumatoid arthritis, discoid lupus, and systemic lupus erythematosus.⁷Recently, numerous reports have appeared in the literature describing the signs and symptoms of chloroquine ocular toxicity.⁸⁻¹⁸Formerly, the ocular side effects were considered transient and reversible.⁵,¹⁹It is now recognized that chronic administration of chloroquine may induce a retinopathy and visual loss which is not reversible. The visual loss may actually progress in severity after the drug is discontinued.⁸,¹⁰ Superficial corneal deposits associated with prolonged chloroquine therapy are visible by slit lamp biomicroscopy. These deposits do not alter