The effect of chloroquine upon the developing eye of the chick embryo.

The effect of chloroquine on the eyes of 8 (8DE) and 15 (15DE) day old chick embryos has been studied. Microphthalmus was observed in 30% of the 8DE and 80% of the 15DE. The most conspicuous changes were seen in the retina. In the 8DE, chloroquine mostly prevented the development of photo-receptors with subsequent adhesions between the pigment epithelium and external granular layer, or caused a destruction of the pigment epithelium with subsequent chorio-retinal adhesions. In the 15DE, chloroquine caused destruction of the whole retina. The choroid showed a hyperproliferation of the melanocytes in the 8DE, and edema in the 15DE. The lens showed moderate vacuolisation in the 8DE and severe cataract formation in the 15DE.