Is corneal deposition of antimalarial any indication of retinal toxicity?

Ninety-five percent of patients on chloroquine demonstrate corneal deposition of the drug with the pupil dilated; less than 10% of patients on hydroxychloroquine show any corneal changes when so examined. I describe one patient on chloroquine and two on hydroxychloroquine who demonstrated large amounts of corneal antimalarial drug, leading to the early diagnosis of definite retinopathy. Examination of the cornea with the pupil dilated may reveal the presence of retinal toxicity in some patients.