PURPOSE: To determine whether the location of a fluorescein-stained line, the Marx line (ML), which runs along the inner eyelid, is correlated with meibomian gland function. DESIGN: Prospective observational case series. METHODS: After applying fluorescein dye solution to the eye, the ML score was calculated for the outer, middle, and inner thirds of the lower eyelid margin. ML scoring was as follows: 0, entirely on the conjunctival side of the meibomian orifices (MOs); 1, part of the ML touches the MOs; 2, ML runs through all of the MOs; and 3, ML runs on the eyelid-margin side of the MOs. Correlations were calculated between the total ML score and age for 251 randomly recruited subjects without acute ocular surface diseases, and between age and the ML score for the three regions of the lower eyelid. Correlations between the regional ML score and the meibographic score, and the meibomian gland secretion score were also determined. The total ML scores of 15 subjects without meibomian gland dysfunction (MGD) were compared with 15 age-matched patients with MGD. RESULTS: The three regions of the lower eyelid had significantly different ML scores. Strong correlations were found between the ML score and age, the meibographic score, and the meibomian gland secretion score. The total ML score of MGD group was significantly higher than that of the non-MGD group. CONCLUSIONS: The strong correlation between the ML score and the meibomian gland scores indicates that the ML score can be used as a simple and rapid screening score for meibomian gland function. PURPOSE: To determine whether the location of a fluorescein-stained line, the Marx line (ML), which runs along the inner eyelid, is correlated with meibomian gland function. DESIGN: Prospective observational case series. the eye, the ML score was calculated for the outer, middle, and inner thirds of the lower eyelid margin. 0, entirely on the conjunctival side of the meibomian orifices (MOs); 1, part of the ML touches the MOs; 2, ML runs through all of the MOs; and 3, ML runs on the eyelid-margin side of the MOs. Correlations were calculated between the total ML scores and age for 251 randomly recruited subjects without acute ocular surface diseases, and between age and the ML score for the three regions of the lower eyelid. Correlations between the regional ML score and the meibographic score, and the meibomian gland secretion score were also determined. The total ML scores of 15 subjects without meibomian g land dysfunction (MGD) were compared with 15 age-matched patients with MGD. RESULTS: The three regions of the lower eyelid had significantly different ML scores. Strong correlations were found between the ML score and age, the meibographic score, and the meibomian gland secretion score. The total ML score of MGD group was significantly higher than that of the non-MGD group. CONCLUSIONS: The strong correlation between the ML score and the meibomian gland scores that that the ML score can be used as a simple and rapid screening score for meibomian gland function.