AIM: To investigate the effects of primary acquired nasolacrimal duct obstruction(PANDO)on the tear film and ocular surface using LipiView ocular surface interferometer and Keratograph 5M anterior segment analyzer.METHODS: A self-controlled clinical trials. A total of 40 patients diagnosed with unilateral PANDO for at least 6mo who were admitted to our department from September 2021 to March 2022 were enrolled in the study, and the healthy eyes of the patients were assessed as control group. The LipiView ocular surface interferometer and Keratograph 5M anterior segment analyzer were used to measure the changes in related parameters of the tear film and ocular surface in both eyes.RESULTS: The non-invasive tear meniscus height(NITMH), stimulated NITMH, loss rate of upper meibomian gland, nasal and temporal ciliary redness index, temporal conjunctival redness index of the affected eyes were higher than healthy eyes(P<0.05), but there were no statistical differences in the non-invasive break-up time(NIBUT), loss rate of lower meibomian gland, nasal conjunctival redness index, dry eye grading, blink responses, partial blink rate and lipid layer thickness(LLT)between the both eyes(P>0.05).CONCLUSION: PANDO may lead to the aggravation of ocular surface inflammation and the loss of upper meibomian gland, and damage the ocular surface of patients. Attention should be paid to the early treatment of PANDO.