A classification for dry eyes following comparison of tear thinning time with Schirmer tear test.
In a double-blind study a non-invasive method of examining the stability of the precorneal tear film was used to record tear thinning time on a population of 34 independently diagnosed dry eye patients. The results were compared with those for tear output, as inferred from the standard Schirmer tear test, and a correlation coefficient of 0.20 determined. The mean tear thinning time and Schirmer results for the population sample were 6.87 +/- 2.97 sec, and 5.62 +/- 5.69 mm wetting in 5 min, respectively. From a plot of tear thinning time against Schirmer a simple classification for dry eyes can be made. A Type A with normal tear stability and low output accounting for 14.70% of the dry eyes. A Type B with low tear stability and normal output, also accounting for 14.70% of the dry eyes. A Type C with low stability (less than 9.84 sec), and low output (less than 11.31 mm wetting in 5 min) accounting for 70.60% of the dry eyes.
Farrell
J
J
Department of Optometry and Vision Science, Glasgow Polytechnic, Scotland.
Grierson
D J
DJ
Patel
S
S
Sturrock
R D
RD
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004311:Double-Blind Method; D015352:Dry Eye Syndromes / Q000145:classification* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007766:Lacrimal Apparatus Diseases / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D013666:Tears / Q000502:physiology*