Spontaneous Eye Blink Patterns in Dry Eye: Clinical Correlations

PURPOSE. To evaluate spontaneous eye blink patterns and their correlations with clinical tests in dry eye disease (DED). METHODS. Twenty-five DED patients and 25 healthy subjects were included in this prospective case-controlled study. Clinical evaluations included the Ocular Surface Disease Index (OSDI), lipid layer thickness (LLT), spontaneous eye blink pattern analysis, fluorescein tear film breakup time (FBUT), and so on. Eye blinks were recorded for 20 seconds with a high-speed camera. Eye blink patterns were divided into the following five phases: the eyelid closing phase (ECP), eyelid closed phase (CDP), early opening phase (EOP), late opening phase (LOP), and interblink intervals (IBI). The correlations between blink parameters and clinical tests were analyzed. RESULTS. Compared with the control group, mean ECP, CDP, and EOP were significantly longer in DED patients (P < 0.001, P 0.029, and P < 0.001, respectively). DED patients also had significantly shorter LOP and blink intervals (both P < 0.001) and more partial blinks as compared with control subjects (P = 0.001). FBUT was negatively correlated with ECP (r = -0.618, P = 0.001) and the number of partial blinks (r = -0.413, P = 0.040). There was a positive correlation between OSDI and the number of partial blinks (r = 0.446, P = 0.026). The LLT coefficient of variation (LLT-CV) also showed a positive correlation with ECP, CDP, and LOP (P = 0.001, P = 0.050, P = 0.049, respectively). Corneal and conjunctival staining was positively correlated with ECP, CDP, and the number of blinks (r = 0.449, P = 0.024; r = 0.526, P = 0.007; r = 0.456, P = 0.022, respectively) and negatively correlated with IBI (r = -0.420, P = 0.037). CONCLUSIONS. Partial blinks, prolonged eyelid closed time and short blink intervals were the three main characteristics of DED patients' spontaneous blink patterns.