|Title||WHICH BLINK PARAMETERS ARE SENSITIVE TO OCULAR SURFACE STIMULATION AND SYMPTOMS?|
|Author, Co-Author||Ziwei Wu, Carolyn Begley, Haixia Liu, Jun Zhang, Linda Adebisi|
|Abstract|| PURPOSE: The purpose of this study was to determine which blink parameters were most sensitive to mild ocular surface stimulation, tear instability and dry eye symptoms.
METHODS: During 2 visits, 10 subjects had 2μl of 2%sodium fluorescein dye instilled, played a computer game (high concentration task: HC) and listened to music (low concentration task: LC) for 2 min with either no stimulus (NS) or with a small fan (FS) blowing on the eye to provide very mild surface stimulation. Two cameras recorded blinking and tear film instability. Custom MATLAB programs analyzed blink and tear film parameters, including interblink interval (BL-IBI), blink amplitude (BL-BA), maximum velocity (BL-Vmax), duration (BL-BD) and the area of tear break-up (TBU). A current symptom questionnaire (CSQ) was given repeatedly.
RESULTS: The BL-IBI decreased significantly with the FS compared with NS: average LC/HC was 4.63± 3.39sec/6.43± 3.28sec for NS and 2.82± 0.78sec/4.59± 3.23sec for FS (p<0.05, one-way ANOVA). BA decreased with the HC compared with LC: average LC/HC was 86±17% /75± 23% for NS and 80± 18% /80± 20% for FS. BL-BA and BL-Vmax were highly correlated under all conditions (r= 0.65± 0.16, p<0.01), but not with BL-BD (r=0.32± 0.29, p>0.05). TBU showed no significant correlations with any blink parameters when pooling whole subjects; however, significant correlations found between TBU and BL-IBI for 7 individual subjects with FS (Spearman’s r=0.53-0.89, p<0.05). IBI and BA were significantly correlated with CSQ dryness, burning or overall symptoms (Spearman’s r= 0.32, p<0.05).
CONCLUSIONS: TBU was correlated with the BL-IBI only with the FS, implying that tear break-up serves as a stimulus for blinking only under ocular surface stress. Blink velocity measures were highly correlated with amplitude, but not with duration, suggesting that fuller blinks were faster, and duration of blinks was similar within subjects. The BL-IBI was the blink parameter most sensitive to ocular surface stimulation, symptoms and task concentration, making it a parameter of choice for clinical studies.
|Affiliation of Co-Authors|