American Board of Ophthalmology (ABO) Practice Exam

The correct sequence of light passing through the eye begins with the cornea, which is the outermost transparent layer that first refracts light as it enters the eye. Next, light travels through the pupil, the opening that allows light to enter the eye, which adjusts in size depending on the amount of light present. The lens then focuses the light further, adjusting its shape to ensure that images are properly focused onto the retina, which is the layer at the back of the eye that captures visual information. Following the lens, the light travels through the vitreous humor, the gel-like substance that fills the eye and helps maintain its shape, before finally reaching the retina.

Understanding this pathway is crucial because each component plays a specific role in the process of vision. The cornea and lens both refract and focus light, while the pupil regulates the amount of light that enters, thus influencing how well we see. The vitreous humor, while not actively refracting light, is essential for keeping the retina properly positioned and for maintaining the overall structure of the eye. This sequence reflects the direct pathway that light follows to ultimately generate visual images on the retina, which are then processed by the brain.