Dry eye syndrome happens when your eyes don’t make enough tears or the tears evaporate too quickly, causing discomfort and irritation. Tears are essential for keeping your eyes moist, smooth, and clear. A healthy tear film has three layers: fatty oils, aqueous fluid, and mucus. These work together to protect and hydrate your eyes. If any layer is disrupted, it can result in dry eyes. Interestingly, dry eyes may also cause excessive tearing because the eyes try to compensate, but these tears are often ineffective. Dry eyes are one of the most common eye problems globally, affecting millions. Studies estimate that 5% to 50% of people experience this condition due to factors like aging, increased screen time, and environmental changes.

This fact sheet is part of our Ophthalmology and Optometry Information Guide series, developed to help people understand eye conditions and their impact on navigating the built environment.