Evaluating the diagnostic ability of two automated non-invasive tear film stability measurement techniques

To evaluate the comparability, discriminative ability, and optimal thresholds for non-invasive tear film breakup time measurements obtained from the Oculus Keratograph 5M and Medmont E300 in detecting other signs and symptoms of dry eye disease, as defined by the TFOS DEWS II diagnostic criteria.

One hundred and thirty-four participants (53 male, 81 female), with a mean ± SD age of 48 ± 20 years, were recruited into a prospective, investigator-masked, diagnostic accuracy study. Dry eye symptomology, tear film parameters (including non-invasive Keratograph and Medmont breakup time), and ocular surface staining were evaluated in a single clinical session.

Significant positive correlation was observed between the two automated instruments (p < 0.001), although non-invasive breakup time measurements obtained from the Medmont were significantly longer (p < 0.001), and demonstrated greater intra-subject and inter-subject variability (all p < 0.001). The areas under the ROC curves exceeded 0.65 for both instruments, and the discriminative abilities were comparable (p = 0.53). The Youden optimal diagnostic threshold for non-invasive tear film stability measurements obtained from the Keratograph was ≤8 seconds, and the optimal cut-off for breakup time measurements obtained from the Medmont was ≤14 seconds.

Despite significant positive correlation, breakup time measurements obtained from the Keratograph and Medmont were not directly interchangeable. Measurements from the Medmont were significantly longer and demonstrated greater intra-subject and inter-subject variability, although the two automated, non-invasive methods for assessing tear film stability exhibited comparable overall performance in diagnosing dry eye disease.