Superior limbic keratoconjunctivitis: multifactorial mechanical pathogenesis

Origins of superior limbic keratoconjunctivitis (SLK) are not well understood. Prompted by suggestions that pressure and friction may contribute to SLK, this paper, using evidence from the literature and from personal Kodachrome records, aims to assess, and if appropriate, enhance this understanding. The survey disclosed evidence confirming mechanical aetiology. Support is presented for the notion that SLK arises from soft tissue microtrauma: (i) between tarsal and bulbar surfaces; and (ii) between conjunctival stroma and sclera. In each pair the two apposed tissues are in repetitive motion relative to each other. It is concluded that SLK arises because nonstandard combinations of multiple predisposing and/or trigger factors exceed the physiological tolerance of mechanical stresses upon the ocular surface and tissues. Through their effects on particular tissues, eight separate stressing forces were perceived. The many contributing factors in four categories are integrated into a new aetiologic concept.