The colored, contractile diaphragm of the eye, situated between the cornea and the lens, regulates the amount of light entering the eye by controlling the size of the pupil. For example, in bright light, this structure constricts the pupil to reduce light intake, while in dim light, it dilates the pupil to allow more light to enter.
This mechanism is crucial for visual perception, enabling the eye to adapt to varying light levels and maintain a clear image on the retina. Historically, the study of this structure has been fundamental to understanding sensory processes and the biological basis of vision. Its function is often explored when discussing sensory adaptation and transduction in psychological contexts.
