The first is the compound eyes, which is situated laterally, and are often visible to our naked eye. The compound eye is composed of many ommatidia, which are in turn composed of several layers. These layers include, from the external to internal, Cornea which serves as the lens, the Coneagen Layer, which is a single layer of cells responsible for excreting the cornea, the retina which is responsible for converting the light stimulus to nervous impulse, and lastly the central nervous connections. The number of ommatidia that an ant may possess in a single lateral eye can be as great as 1,200 in the male of Formica pratensis , to 1 in the eye of workers of Ponera punctatissima , to zero in the worker of the African driver ant. The second type of eye is the ocelli, or simple eye.
Most ants have three such eyes on the vertex of the cranium, placed in a triangle.
The ocelli are of a different construction from the compound eyes, a fact that is thought by some to indicate that ocelli are ancient structures, evolved long before compound eyes. Ants that have no compound eyes generally do not have ocelli either. The antennae are by far the ant's most important sensory input devices. They are multi-jointed, with the first segment comprising the scape, while the remaining segments comprise the funiculas. The first segment, the scape, is elongated in females.