What is the hallmark sign of a detached retina?

The hallmark sign of a detached retina includes experiencing sudden flashes of light and the perception of a shadow or curtain effect over the vision. This phenomenon occurs because the retina, which is crucial for clear vision, becomes either partially or completely separated from the underlying tissue. The flashes of light, or photopsia, arise from the disruption of retinal neuronal function when the retina is pulled or tugged. Additionally, as the retina detaches, it can create the sensation of a shadow or curtain obstructing the visual field, indicating a risk of significant visual loss if not addressed promptly.

The other options do not accurately represent the symptoms associated with retinal detachment. Sudden loss of hearing is unrelated, while blurred vision in daylight and increased sensitivity to light are not specific to this condition. Recognizing the specific signs of a detached retina is crucial for timely evaluation and management, as prompt treatment can help preserve vision.