Research into the application of tear film breakup time (TBUT) to monitor dry eye disease (DED) now shows that patients can be categorized into 2 groups based on their tear ﬁlm break-up patterns (TBUP), a report published in Eye & Contact Lens shows. The study suggests that the classification of these patients into 1 of the 2 groups can help differentiate DED pathophysiology and guide treatment decisions.
Researchers examined 91 eyes of 91 patients with DED and analyzed their TBUP. Participants were diagnosed with DED based on the presence of subjective symptoms, per the ocular surface disease index (OSDI) and subjectively, using either TBUT (less than 10 seconds) or positive corneal fluorescein staining. TBUP were evaluated using a slit lamp after fluorescein staining. Based on patterns recorded during that exam, patients were divided into 2 groups: the “dot” break- up pattern group (group I) and “random” break-up pattern group (group II).
“The dot break-up pattern comprised small dot-like popping breaks. Multiple dots were observed in most patients in group I,” the study explains. “By contrast, the random break-up pattern comprised wavy, smooth, and undulating wide cracks that were observed when the eye was open without any popping dot break-up patterns. The cracks look like wavy ﬂoating oil on water.”
Clinical severity of dry eye was evaluated using the Oxford stain score system (OSS), TBUT, and OSDI responses. Data collection also included the concentration of inflammatory cytokines and mucin in the tears and conjunctival tissue.
Results revealed that group I had a statistically lower TBUT and higher OSS scores compared with group II. Group I had higher concentrations of interleukin (IL) -6 and IL-8, and impression cytology shows that group I had higher IL-1b and IL-8 compared with group II. However, the OSDI results were not statistically significant between group I and group II.
The results suggest that “dot” break-up patterns are linked to DED with inflammation rather than tear film instability, and that “random” tear breakup times are more likely due to tear film instability, rather than inflammation.
This deviation can help physicians determine if treatment should target the patient’s tear film itself or underlying inflammation, the report says. “Inﬂammation induces apoptosis and necrosis of the surface epithelial cells, and cell destruction is thought to result in irregular hydrophilicity of the ocular surface and the splitting of the tears into a dot-like pattern in the relatively more hydrophobic regions. Therefore, patients with this form of DED should primarily be treated for the inﬂammation of the ocular surface, and the focus should be on helping them regenerate the corneal epithelial cells,” the study explains. Conversely, the mechanism of disease in patients with random TBUP is related to the instability of the tear ﬁlm and should be treated with a focus on stabilizing it.
Researchers did note 3 limitations to the study. Some patients had more than 1 pattern at the same time, the sample size was relatively small, and they were unable to directly demonstrate irregular hydrophilicity and surface irregularities in either of the patterns.
Eom HD, Jung JU, Lee KP, et al. Simplified classification of tear film break-up patterns and their clinicopathological correlations in patients with dry eye disease. Eye Contact Lens. 2021;47(1):15-19. doi:10.1097/ICL.0000000000000706