The “Setting Sun” sign: A proposed grading scale

The “Setting Sun” sign is a neuro-ophthalmic finding observed in infants with hydrocephalus, characterized by conjugate downgaze due to pressure effects on the posterior third ventricle and midbrain. This sign can be perceived in about third of infants with obstructive hydrocephalus, and could serve as an early clinical indicator for the progression in intracranial pressure. Despite its significance, there is a paucity of  standardization to quantify the hydrocephalus severity, limiting objective assessment and monitoring. Here, we propose a novel, simple and sensitive grading system based on the degree of iris and pupil coverage by the lower eyelid. This system aims to enhance early detection, facilitate disease monitoring, and improve treatment decision-making in the management of infantile hydrocephalus