Columnar keratopathy: an early manifestation of limbal stem cell deficiency

•Columnar Keratopathy is a distinct clinical entity that represents an early sign of limbal stem cell deficiency.•Columns of late fluorescein staining metaplastic/conjunctival epithelial cells extend from the limbus to the central cornea.•These alternate with columns of clinically normal epithelium that do not show late staining.•The late staining columns correspond to areas of loss of limbal architecture.•They are seen in a range of conditions, all of which are known causes of limbal stem cell deficiency.