Which of the following is a potential side effect of eye drops that may cause problems?

Stinging and blurring are recognized potential side effects of many types of eye drops, particularly those that may contain preservatives or active ingredients that can cause irritation. These sensations are typically temporary but can lead to discomfort and may interfere with the patient's ability to drive or operate machinery until the blurring resolves.

The other options, such as increased vision or improved night vision, are generally not classified as side effects; rather, they may be intended effects of certain eye drops designed to correct vision issues. However, they are not universally applicable to all eye drops. The claim that eye drops are completely safe without any potential side effects is an overstatement. While many patients may tolerate them well, side effects do exist and can impact the user experience and safety, making the acknowledgment of stinging and blurring as a side effect important for individuals taking these medications.