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Classically, the stability of the lacrimal film is due to the surfacting of the epithelial surface by the mucus produced by the goblet cells. However, there are many objections to this hypothesis. Deducing from electron microscopy of the epithelial cells, which shows vesicles in the superficial layer and glycocalix threads on the microvilli and other clinical facts, we think that the surfacting agent is not mucus but glycocalix. The disappearance of goblet cells during sicca syndrome is not the cause but the result of the dryness. Epithelial cell integrity is essential for the stability of the tear film and therapeutics must aim at regenerating these cells rather than only replacing the lacrimal film by tear substitute.

A study of tear ferning patterns in normal and keratoconjunctivitis sicca eyes led to the classification into 4 types by Rolando [1984]. We practised this in our laboratory and observed specific and distinct tear ferning patterns for electrophoretic types 1 and 2 which Liotet et al. [1983] described as abnormal tear proteins modification found in patients who repeatedly and rapidly clog their hydrophilic lenses. In a general way, a study of tear ferning patterns can result in an appreciation of tear quality in contactology.

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