Fluorescein Dye Improves Microscopic Evaluation and Counting of Demodex in Blepharitis With Cylindrical Dandruff

PURPOSE: To show whether fluorescein dye helps detect and count Demodex embedded in cylindrical dandruff (CD) of epilated eyelashes from patients with blepharitis. METHODS: Two eyelashes with CD were removed from each lid of 10 consecutive patients with blepharitis and subjected to microscopic examination with and without fluorescein solution to detect and count Demodex mites. RESULTS: Of 80 eyelashes examined, 36 (45%) lashes retained their CD after removal. Before addition of the fluorescein solution, the mean total Demodex count per patient was 14.9 +/- 10 and the mean Demodex count per lash was 3.1 +/- 2.5 and 0.8 +/- 0.7 in epilated eyelashes with and without retained CD, respectively (P < 0.0001). After addition of the fluorescein solution, opaque and compact CD instantly expanded to reveal embedded mites in a yellowish and semitransparent background. As a result, the mean total Demodex count per patient was significantly increased to 20.2 +/- 13.8 (P = 0.003), and the mean count per lash was significantly increased to 4.4 +/- 2.8 and 1 +/- 0.8 in eyelashes with and without retained CD (P < 0.0001 and P = 0.007), respectively. This new method yielded more mites in 8 of 10 patients and allowed mites to be detected in 3 lashes with retained CD and 1 lash without retained CD that had an initial count of zero. CONCLUSIONS: Addition of fluorescein solution after mounting further increases the proficiency of detecting and counting mites embedded in CD of epilated eyelashes.