single-chambered eye

A single-chambered eye, also known as a simple eye, is a basic visual organ that uses a single lens to focus light onto photoreceptors. These eyes are concave structures, differing from compound eyes which have multiple lenses.123

Pigment cup eyes, an early form of single-chambered eyes, consist of a cup of pigment cells containing photoreceptors. They can detect the general direction of light, aiding in finding food, but offer limited resolution for hunting or evading predators. Corneal eyes, found in vertebrates and some invertebrates like spiders, utilize a cornea as a refracting lens to form images. In humans, the cornea provides about two-thirds of the eye's focusing power, with the lens contributing the remaining third.324