Purpose. To develop a non-invasive nethod to quantity the precorneal Hpid film stability. Methods. Four normal, two 30-35 year-old males and two 9 year-old bol scouts, were examined under the slit lamp biomicroscopy through a Tcarscope (Keeler Ltd Inc., UK). The color interference images of the precorneal tear film during several normal blinks were taken by a Panasonic digital camera and recorded in a Super VHS video film. These serkl frames of images were registered, digitized and subtracted from the iris background image using the Metlab software (Mathworks Inc.). From the remaining image, the intensity of three rectangular windows of 50x100 pi was recorded at the area inferotemporal (#1), directly inferior (#2) and inferonasal (#3) to the pupil. Changes if the summed intensity between blinks were then plotted against time. Results. All 4 normals showed a similar pattern for these three windows. The intensity increased immediately following eye openning, and reached a stable plateau after a mean ( f 0.53 sec and lasting for variable lengths of îime until the next blink. Window #1 maintained the most stable plateau, #3 had most unstable plateau that followed an interv il longer than #1, or never reached a plateau, and #2 had either a curve more resembling #1 with the exception that the plateau was not as stable, or intermediate between H] and #3. Conclusion. Collectively, these data indicate a consistent difference in the stability of the precorneal lipid tear film on these three different corneal surfaces. B;.seline data established as such can be used lo evaluate patients with an unstable tear fi m.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|Publication status||Published - 1997|
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