Analysis of the first tear film break-up point in Sjogren's syndrome and non-Sjogren's syndrome dry eye patients

Background Tear film instability plays an important role in the course of Sjogren's Syndrome dry eye (SSDE) even though it is generally classified as aqueous-deficient dry eye. The measurement of the first tear film break-up point (FTBUP) helps to evaluate the most unstable position of the tear film on ocular surface. We aim to investigate FTBUP in Sjogren's Syndrome dry eye (SSDE) and non-Sjogren's Syndrome dry eye (NSSDE) patients, and explore its correlation with dry eye indices. Methods Twenty-two SSDE patients (44 eyes) and 22 NSSDE patients (44 eyes) were enrolled in the study. Oculus Keratograph K5M was used to measure FTBUP, the first and average non-invasive keratographic breakup time (f-NIKBUT and av-NIKBUT), the tear meniscus height, and meibomian gland dropout. Other tests of tear film were also performed including Ocular Surface Dryness Index (OSDI), Schirmer I test, fluorescein break-up time and corneal fluorescein staining. Dry eye indices and the locations of the FTBUP were compared between SSDE and NSSDE patients. Generalized estimating equation (GEE) was used to ajusted the correlations between right and left eyes. The correlations between the FTBUP and ocular symptoms and signs were investigated using Pearson's correlation coefficient test. Results The FTBUP occurred at the supranasal quadrant in 12/88 eyes, supratemporal quadrant in 8/88 eyes, inferonasal quadrant in 34/88 eyes, and inferotemporal quadrant in 34/88 eyes. The percentage eyes with inferior FTBUP was significantly higher in the SSDE than in the NSSDE subjects (86.3% vs 68.1%, P = .049). Moreover, in SSDE subjects, temporal breakup point was seen more often in those who presented corneal fluorescein staining in any location, while nasal breakup point was more frequent in those who did not present any corneal fluorescein staining (P = .045). Conclusion The location of the FTBUP in SSDE patients had specific characteristics. However, the diagnostic potential of FTBUP in early recognition of SSDE needs further validation.