Which of the following is a common symptom of dry eye?

The common symptom of dry eye that is often seen is excessive tearing. This might seem counterintuitive, as one might expect that dry eyes would not lead to tearing. However, dry eye syndrome can lead to a paradoxical response where the body tries to compensate for the lack of moisture by producing more tears. These tears, however, can be of poor quality, leading to instability and discomfort.

In dry eye conditions, the tear film may break down more quickly than normal. When this happens, people can experience increased tear production as the eyes attempt to maintain moisture. Therefore, while the quality of the tears may be compromised, the presence of excessive tearing is indeed a symptom associated with dry eye syndrome.

The other symptoms listed, while they can be related to various eye conditions, are not typical for dry eye syndrome. Increased blinking can occur as a response to discomfort, but it isn't a defining symptom. Eye swelling may occur due to inflammation or allergic reactions, and vision blur can happen with various conditions, not just dry eye. However, in the context of dry eye specifically, excessive tearing stands out as a notable symptom.