Abstract: Objective: This study aimed to explore the value of monoenergetic imaging using dual-layer spectral detector computed tomography (CT) for dacryocystography. Methods: Dacryocystography was performed in patients with clinically suspected lacrimal duct obstruction using a Philips IQon dual-layer spectral detector CT. The objective evaluation included the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of each monoenergetic image, subjective rating of image quality, and the site and degree of lacrimal duct obstruction. Results: The SNR and CNR of 50 keV images was 9.76±13.44 and 10.24±13.88, respectively, which were significantly lower than that of 70~200 keV images. The subjective scores for 50 keV and conventional image quality were (5, 5) and (4, 5), respectively, indicating good consistency in subjective scores among radiologists. Conclusion: The SNR and CNR of CT dacryocystography increased significantly at 50 keV.