Approximately what percentage of tear volume drains through the nasolacrimal system?

The correct answer reflects that approximately 75% of tear volume drains through the nasolacrimal system. This high percentage underscores the efficiency of this drainage mechanism in maintaining ocular surface homeostasis and managing tear volume.

Tears are produced by the lacrimal glands and spread across the ocular surface during blinking. After serving their purpose of nourishing and lubricating the eye, a significant portion of these tears is then drained through the small puncta located at the eyelid margins into the nasolacrimal duct. This process is essential not only for maintaining a clear optical surface but also for preventing excessive tear overflow, which can lead to tearing or epiphora.

Understanding the mechanics of tear drainage is crucial in assessing various ocular conditions, as dysfunction in the nasolacrimal system can lead to dry eye symptoms or excessive tearing. This information helps inform diagnostic assessments and therapeutic interventions in ocular surface diseases.