Purpose:To evaluate optical coherence tomography meibography (OCT-M) in patients with and without obstructive meibomian gland dysfunction (MGD) and to determine the relationship between OCT-M and ocular surface clinical tests.Methods:Twenty-two patients with MGD and 16 control subjects were included. Each patient underwent an evaluation of ocular surface disease symptoms, lid margin abnormality score, lipid layer thickness evaluation, and meibomian gland (MG) morphological changes using noncontact infrared meibography and OCT-M. OCT-M scans were acquired in 4 different locations. OCT-M parameters including the MG length and width and palpebral conjunctival thickness were evaluated.Results:Within the OCT-M parameters, the mean length and width of MGs were significantly decreased in patients with MGD (310 60 m and 214 +/- 30 m, respectively) compared with the control group (361 +/- 53 m, P = 0.041 and 264 +/- 41 m, P = 0.021, respectively). The mean conjunctival thickness was also significantly increased in patients with MGD (448 +/- 68 m) than in the control group (356 +/- 59 m, P = 0.03). The mean length of MGs was correlated with symptoms (r = 0.34, P = 0.034), and the mean MG width was correlated with tear film breakup time (r = -0.412, P = 0.009) and the lid margin abnormality score (r = 0.334, P = 0.038).Conclusions:The MG length and width were significantly decreased in patients with MGD than in the control group. These parameters were correlated to both ocular surface symptoms and clinical signs. This new imaging technique may be a useful tool for MGD evaluation.