Which sign indicates an abnormal bulging of the eyelid related to keratoconus?

Munson's sign specifically indicates an abnormal bulging of the eyelid associated with keratoconus. This sign is characterized by a downward and outward bulging of the lower eyelid when the patient looks down. This phenomenon occurs due to the protrusion of the cornea in keratoconus, leading to this distinctive ocular appearance.

Keratoconus is a progressive eye condition where the cornea becomes thin and conical, resulting in distorted vision. As such, recognizing Munson's sign can be crucial for diagnosis because it provides a visual understanding of the disease's physical effects on the eyelid and cornea.

Other signs listed in the options serve different purposes and are associated with different conditions. For example, Horner's sign relates to a disruption of sympathetic nerves leading to ptosis and miosis, while the Rosenbaum sign is used for near vision testing. Babinski sign is indicative of neurological issues involving the corticospinal tract, particularly in infants versus adults. Thus, while those signs are important in their respective contexts, they do not indicate the abnormal bulging of the eyelids that is characteristic of keratoconus.