Which Purkinje image is located behind the posterior lens?

The Purkinje images are reflections of a light source from the surfaces of the eye's optical elements, such as the cornea and the lens. Specifically, there are four distinct Purkinje images identified as PS 1, PS 2, PS 3, and PS 4, categorized based on the surfaces from which they are reflected.

The first purkinje image, PS 1, is the reflection from the front surface of the cornea, while PS 2 is the reflection from the back surface of the cornea. PS 3 is produced by the front surface of the lens, and finally, PS 4 represents the reflection from the rear surface of the lens.

Given this context, identifying PS 4 as the correct answer makes sense, as it is specifically the Purkinje image that is formed at the back surface of the lens, positioning it behind the posterior lens. This understanding of the location of the Purkinje images is crucial in visual perception and ocular optics, as it helps clarify how light interacts with different components of the eye.