Figure 1.

Symptoms and causes of dry eye disease (DED). There is a wide range of symptoms of DED, including irritation, redness, blurry vision, tearing, light sensitivity, and mucus secretion (a). Amongst other factors, meibomian gland dysfunction is a leading cause of DED, disrupting the tear film lipid layer by affecting the rate of tear evaporation. A specific meibomian gland feature often observed in patients with DED is shortened glands, i.e., glands that do not extend to their full normal length (arrows in the meibography (b)).