Ocular changes in swine associated with chloroquine toxicity.

Ocular changes associated with long-term chloroquine administration have been the subject of considerable interest to ophthal­ mologists and pathologists. In man, changes are most often associated with therapy for discoid or systemic lupus erythematosus. Functional changes include central scotoma, loss of visual acuity, constriction of periph­ eral fields and defective color vision.Reti­ nal vessels may be attenuated and electroretinograms are abnormal in advanced cases. The principal morphologic changes in these cases are a destructive loss of rods and cones, a migration of pigment from the pigmented epithelium to the inner and outer nu­ clear layers, ganglion cell destruction, corneal edema and deposits, and arteriolar occlusion. The most significant, and apparently irre­ versible, ocular changes associated with long-term chloroquine therapy are those in the retina; these may result in permanent impairment of vision. Scherbel describes so-called typical chloroquine retinopathy as " . . . showing granular or stippled pigmenta­ tion of the macula, or patchy macular depigmentation surrounded by a clear zone that is encircled by another irregular concentric ring of pigment, thus resembling a doughnut or bullseye."