Which symptom might indicate the presence of optic neuritis?

The symptom that indicates the presence of optic neuritis is a painful sensation during eye movements. Optic neuritis is an inflammation of the optic nerve, which often leads to symptoms that include visual disturbances and discomfort. The pain, particularly when moving the eyes, is a hallmark feature of this condition. It may precede or accompany changes in vision, such as blurriness or loss of vision, but the notable pain during movement serves as a significant indicator for diagnosing optic neuritis.

In comparison, difficulty seeing at night pertains more likely to issues with rod function in the retina or other types of visual impairment, rather than specifically signaling optic neuritis. Sudden loss of peripheral vision may suggest other conditions affecting the optic pathway or retina, and constant headaches are nonspecific symptoms that could indicate a variety of neurological problems but are not directly linked to optic neuritis. Thus, the presence of pain during eye movements distinctly aligns with the characteristics of optic neuritis, making it the correct response.