1- The eye of the snail Biomphalaria glabrata was studied at the light microscope level. The eye is a spherical lens bathed in humor (vitreous body) and surrounded by the corneal and retinal cell layers. 2- The retina is composed of four layers: the inner photoreceptor layer close to the ocellar cavity, a pigmented layer, a nuclear layer, and the fibrous layer. The nuclear layer contains the nuclei of the supporting cells and of two types of sensory cells that are similar to those described for other gastropod molluscs. 3- Calculations of optical properties showed that the eye of B. glabrata is slightly hypermetropic and has limited resolving power. 4- The results are discussed in terms of the importance of visual information for the behavior of this animal.