The Contribution of Lipid Layer Movement to Tear Film Thinning and Breakup

摘要: PURPOSE. To investigate whether the tear film thinning between blinks is caused by evaporation or tangential flow of along surface cornea. Tangential was studied measuring movement lipid layer. METHODS. Four video recordings layer were made from 16 normal subjects, with subjects keeping their eyes open for up to 30 seconds after a blink. assess vertical and horizontal stretching underlying aqueous layer, analyzed at five positions, middle position 1 mm below corneal center, four positions respectively above, below, nasal, temporal this position. In addition, in 13 blink measured. RESULTS. The total upward could be fitted sum an exponential decay plus slow steady drift; drift 14 (P = 0.002). Areas thick seen expand causing downward movement. velocity initial rapid time constant found correlate significantly thickness but not tear-thinning rate. CONCLUSIONS. Analysis indicated that observed too explain rate film. Appendix, it shown under stationary cannot It concluded most due evaporation.