Location and pattern of non-invasive keratographic tear film break-up according to dry eye disease subtypes

Purpose To compare the non-invasive keratographic tear film break-up time (NIKBUT) and the location and pattern of non-invasive keratographic tear film break-up between normal group and each group of three dry eye disease (DED) subtypes. Methods We enrolled 55 normal subjects and 250 patients with DED, who underwent tear meniscus height and NIKBUT measurements using the Keratograph 5M. Ocular surface parameter assessments such as the fluorescein tear break-up time, ocular surface staining, Schirmer's test, and lid margin and meibomian gland examinations were performed, and the ocular surface disease index was determined. These parameters, including the proportion of the first tear film break-up location and simultaneous multiple tear film break-up pattern, were compared amongst the normal and DED subtypes. Results Aqueous-deficient dry eye disease (ADDE) and ADDE/meibomian gland dysfunction (MGD) subtypes showed lower NIKBUTs than those of the normal group, whilst NIKBUTs of the MGD subtype did not differ from those of the normal group. The NIKBUTs showed a good diagnostic ability in diagnosing dry eye except MGD only. The occurrence of the first tear film break-up in the central location was significantly higher in both the ADDE and ADDE/MGD subtypes, comprising approximately 40% in both subtypes (p < 0.001). The proportion of a simultaneous multiple tear film break-up pattern was higher in the ADDE and ADDE/MGD subtypes, at 60.9% and 45.5%, respectively (p < 0.001). Conclusion The NIKBUTs and the location and pattern of non-invasive tear film break-up were different between normal group and each group of three DED subtypes.