What Is a Dellen?
A dellen is a shallow, localized dip on the corneal surface caused by tissue dehydration. The small hollow area usually forms next to a raised area such as a scar, pterygium, or recently healed surgical site. Because the tear film does not spread evenly across the dip, the tissue dries more easily and becomes thinner. People often notice blur, irritation, or a rough sensation around the affected spot. An eye exam can confirm the depth and location of the thinning.
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