What type of structural abnormality does the valve of Hasner relate to in infants?

The valve of Hasner is an anatomical structure located at the nasolacrimal duct's end, which plays a crucial role in tear drainage from the eye to the nasal cavity. In infants, this valve can sometimes be functionally inadequate, leading to issues with proper tear drainage. This inadequacy results in tears accumulating in the conjunctival sac, which can lead to a condition known as congenital nasolacrimal duct obstruction.

Inadequate tear drainage occurs when tears that normally flow down through the nasolacrimal duct to the nasal passage are insufficiently channeled due to the valve of Hasner not opening adequately. This can manifest as watery eyes or excessive tearing in infants, commonly referred to as epiphora. Understanding this condition is essential for recognizing and managing possible tear drainage issues in young children.