The Lid Wiper – a specialized structure at the inner eyelid margin for distribution of the tear film

Abstract

AbstractPurpose The lid wiper is an epithelial structure at the inner eyelid border that distributes the thin precorneal tear film during the up‐phase of the blink. Clinically it is the first area of the ocular surface that shows epithelial alterations in dry eye disease.Methods A literature review on the posterior lid margin and lid wiper is discussed together with own data and considerations of the relevance of the lid wiper region in ocular surface physiology and pathology.Results The posterior side of the inner lid border has an epithelium of conjunctival morphology with goblet cells. It forms an elevation of about 100µm (10‐12 cell layers) thickness immediately at the crest of the inner border with a slope towards the subtarsal fold. The lid wiper hence forms a distinct epithelial lip that is the only region of the upper lid in contact with the globe as verified by functional tests. It extends along the upper and lower eyelid margins, has a width of typically about 1mm, narrower in the middle and wider to the temporal and nasal sides. The lid wiper of the upper lid appears as a suitable device to distribute the thin precorneal tear film during the blink as supported by the finding that in conditions with increased friction, such as dry eye disease and contact lens wear, the lid wiper is the first zone of the ocular surface that shows a pathological vital staining indicating epithelial destruction.Conclusion The lid wiper is of underestimated importance for tear film distribution and ocular surface integrity as well as a sensitive early indicator of dry eye disease. Integration and scoring of lid wiper epitheliopathy in dry eye diagnosis and therapy schemes could be a valuable addition to clinical practice. Support DFG KN317/11