Abstract
Purpose :
To investigate the spatial distribution of the tear-film break-up time via noninvasive Keratograph in normal subjects and patients with dry eye syndrome (DES).
Methods :
A total of 88 subjects (mean age = 35.2 ± 16.8 years) participated in the study. Subjects were separated into normal and DES group based on the results from the subjective questionnaires (McMonnies Questionnaire) and conventional break-up time assessments (TBUT test). In noninvasive evaluation (Keratograph4, Oculus), the tear film stability was recorded for 24 seconds continuously. The pre-corneal tear film was divided into 192 small sections. Whether each section broke, and the break-up time, if it did, was recorded. Noninvasive first break-up time (NIBUT-f) was the first break-up time among the 192 sections and average break-up time (NIBUT-av) is the mean value of the break-up time for those sections broke during recording. The 192 sections were further grouped into superior (10:30-1:30 clock), nasal (1:30-4:30 clock), inferior (4:30-7:30 clock), and temporal (7:30-10:30 clock) quadrants to reveal the spatial variation. From each subject, only the right eye's data were included in the analysis.
Results :
When compared to the normal subjects, NIBUT-f was only significantly shorter in temporal (7.41±7.00 vs. 13.12±9.32s, p=0.03) and inferior (6.86±5.73 vs. 11.16±8.73s, p=0.04) quadrants of DES subjects, while other quadrants showed no significant difference between groups (T-test, p>0.05). For NIBUT-av, the only significant difference between normal subjects and subjects with DES existed in the inferior quadrant (11.61±7.98 vs. 16.90±8.34s, p=0.03), while other quadrants showed no difference between groups (T-test, p>0.05). Comparing the percentage of sections broken during the recording time, the only significant difference between the normal and DES subjects found was in the inferior quadrant (chi-square test, p<0.05). This difference reached the peak at 15 seconds and declined afterward. Other quadrants showed no significance (chi-square test, p>0.05).
Conclusions :
Tear break-up is not homogenously distributed, with sections in the inferior quadrant are more likely to break and break early. The significant difference between normal and DES subjects is more likely to be found in the inferior quadrant.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.