Researchers from the University of California recently found that the Pain Sensitivity Questionnaire is associated with the “maximum interblink period” (MIBP) length, even after adjusting for ocular surface conditions. This suggests pain sensitivity plays a role in influencing how ocular discomfort is perceived, they note.

The study evaluated 42 patients over the course of two days and four visits. After patients completed the Pain Sensitivity Questionnaire to quantify their pain sensitivity levels, the team of researchers then assessed each participant’s exposed interpalpebral area, tear meniscus height, tear-film lipid layer thickness, ocular surface cooling rate and noninvasive tear break-up time. The patients were asked to refrain from blinking until they felt discomfort—a period of time that was termed the MIBP—and simultaneously had their ocular surface cooling rate measured.

The team found that a longer MIBP was associated with decreased pain sensitivity, a lower ocular surface cooling rate and Asian ethnicity. The researchers estimate that, based on the results of the mixed-effect model, patients should be able to refrain from blinking for an additional four seconds if they had the lowest (0.6) compared with the highest (6.1) pain sensitivity in the study. 

Li W, Lin MC. Pain sensitivity associated with the length of the maximum interblink period. Invest Ophthalmol Vis Sci. 2018;59:238-45.