AIM: To compare the non-invasive tear break-up time(NITBUT)and tear meniscus height(TMH)measurements in keratoconus patients and normal subjects, and to determine the relationship between these measurements with keratoconus disease by the Oculus Keratograph 5M(K5M).

METHODS:Fifty keratoconus patients(100 eyes)and 50 healthy subjects(100 eyes)participated in the study. The age range in keratoconus group was 15-60(mean ± standard deviation=28.33±8.60)y, and in control group was 18-60(26.25±1.11)y. The measurements of NITBUT and TMH were performed using the K5M.

RESULTS: The mean value of NITBUT between the keratoconus group and the control group showed no statistically significant different(P=0.58). Also, the mean of TMH between two groups was not significantly different(P=0.69). The results of correlation coefficient between the variables of the study demonstrated that there was no significant relationship between the NITBUT and TMH measurements with the two groups(keratoconus group: r= 0.053, P=0.721; control group; r=-0.0501, P=0.7098).

CONCLUSION: Our study shows that the presence of keratoconus has no clinically significant impact on the quality and quantity of tear film.