Table 6. Positive and negative predictive values of NIBUT and TBUT in the first, second and third measurement of the right eye in study patients.

	PPV (%)	NPV (%)	PPV (%)	NPV (%)
NIBUT 1st testing	81.48	57.69	79.31	61.90	TBUT 1st testing
NIBUT 2nd testing	92.00	68.00	85.71	68.18	TBUT 2nd testing
NIBUT 3rd testing	87.50	60.87	88.88	69.57	TBUT 3rd testing

PPV = positive predictive value; NPV = negative predictive value; NIBUT = noninvasive break-up time; TBUT = tear break-up time