Studies on staining test for keratoconjunctivitis sicca. I. Quantization of fluorescein test by image analysis
Iishi, A.
Nippon Ganka Gakkai Zasshi 89(12): 1359-1365
1985
ISSN/ISBN: 0029-0203 PMID: 2421556 Document Number: 254817
Fluorescein test is indispensable for diagnosis of keratoconjunctivitis sicca in Sjogren's disease. However, evaluation of the test has been qualitative and indistinct. This study made it possible to quantize the fluorescein test with image processing. Twenty eyes of keratoconjunctivitis sicca were subjected to study. The cornea was stained with 2% fluorescein and photographed on black-and-white film. The photographs were initially processed and projected on the video display terminal on which the fluorescein-stained area and the surface area of the cornea were computed secondary and converted into square millimeters. The ratio between the fluorescein-stained area and the corneal surface area (F/C ratio) was calculated. The program of the calculation included the correction subroutine where the three-dimensional and aspherical attribute of the corneal surface was well regarded. The F/C ratio ranged from 0.15 to 49.30% and average value was 11.01%. The mean surface area of the cornea was 129.29 .+-. 5.640 (SD) mm2. This method is useful in diagnosis, evaluation of the effects of some therapy, or clinical observations in keratoconjunctivitis sicca.