%0 Journal Article
%A IWATA, SHUZO
%A LEMP, MICHAEL A.
%A HOLLY, FRANK J.
%A DOHLMAN, CLAES H.
%T Evaporation rate of water from the precorneal tear film and cornea in the rabbit
%B Investigative Ophthalmology & Visual Science
%D 1969
%J Investigative Ophthalmology & Visual Science
%V 8
%N 6
%P 613-619
%@ 1552-5783
%X A technique for the study of evaporation from the precorneal and corneal surfaces has been developed. Evaporation from the superficial lipid layer (SLL) has been measured to be 10.1 x 10-7 Gm.cm.-2sec-1 When this lipid layer is removed, evaporation increases around fourfold. Evaporation from the dry epithelial surface occurs at a rate of 1.8 x 10-7 Gm.cm.-2sec-1 After the epithelium is removed, a twentyfold increase in evaporation rate occurs. The specific resistances (u) to evaporation of these layers have been calculated: epithelium, = 82.5 sec./cm.; SLL,= 12.9 sec/cm.; aqueous tears, ≤ 1 sec/cm.; stroma, ≤ 0 sec./cm. Thus, the superficial lipid layer is effective in retarding evaporation of the precorneal tear film. Its effectiveness compares favorably to that of condensed monolayers of long-chain fatty alcohols on pure water, known to be efficient in retarding evaporation. The epithelium functions as a barrier to water flow and is highly effective in retarding evaporation in the absence of a tear film.
%[ 4/18/2021