Which symptom is commonly associated with dry eye syndrome?

Blurred vision is a symptom commonly associated with dry eye syndrome because when the eyes lack sufficient moisture, the tear film can become unstable. This instability can lead to fluctuations in vision clarity and cause the blurred vision often reported by individuals suffering from this condition. The tear film plays a critical role in providing a smooth optical surface on the cornea, and without adequate lubrication, images cannot focus properly, resulting in visual disturbances.

The other symptoms mentioned, such as severe headaches, night blindness, and increased tears, are not typical indicators of dry eye syndrome. While increased tears may seem related, in the context of dry eye, the body often compensates for dryness by producing more tears which can cause tears to spill over, rather than indicating that dry eyes are present.