Chloroquine retinopathy is a drug disease that can be prevented. Among some suggested methods, fluorescence electroretinography allows an evaluation of drug retinal deposit. In fact if a fluorescent substance accumulates in the retinal cells, a very short wavelength stimulus can produce a bioelectric response. If soon detected drug absorption is reversible. Only in a long run, the drug can induce irreversible damages. Thus the importance of continuous control of the patients in treatment with chloroquine-drugs is necessary. In this study the results of an investigation of 38 patients treated with synthetic anit-malarial drugs are shown. In some subjects the presence of the drug in the retina, without anatomic lesions, was demonstrated. These deposits disappeared upon cessation of the treatment. Deposits with or without retinal lesions were noticed in 31% of the observed subjects. In these patients the suspension of drug administration reduced accumulation but did not influence retinal lesion shown by fluorangiography. The authors hypothesized that fluorescent substance deposit is made easier by retinal vasculopathy due to connective tissue disorders.