Relationship between Corneal Sensation, Blinking, and Tear Film Quality.
To examine the possible role of corneal sensitivity and tear film quality in triggering a blink by investigating the relationship between blink rate, central corneal sensitivity threshold (CST), ocular surface temperature (OST), tear meniscus height (TMH), tear film quality (noninvasive tear break-up time [NIBUT]), and tear film lipid pattern under normal conditions.



Forty-two volunteers (average age, 27.76 ± 5.36 years; 11 males) with good ocular health (Ocular Surface Disease Index, <15.0) were recruited for this cross-sectional cohort study. Blink rate, CST (noncontact corneal air gas aesthesiometry, NCCA), minimum and maximum OST in the central and inferior cornea between blinks (thermal infrared camera), TMH, NIBUT, and lipid pattern of the tear film (Keeler Tearscope Plus) were recorded on the right eye only.



Median blink rate was 11 blinks/min (interquartile range [IR], 6.95 to 17.05), CST was 0.35 mbars (IR, 0.30 to 0.40), minimum OST in the central cornea was 35.15°C (IR, 34.58 to 35.50), and NIBUT was 34.55 s (IR, 12.45 to 53.80). Moderate but statistically significant correlations were observed between CST and NIBUT (r = 0.535, p < 0.001), CST and blink rate (r = -0.398, p < 0.001), lipid pattern and OST (r = 0.556, p < 0.001), and between CST and OST (r = 0.371, p = 0.008). The correlations between blink rate and NIBUT (r = -0.696, p < 0.001) and between OST and NIBUT (r = 0.639, p < 0.001; Spearman test) achieved higher significance; this was highlighted by the linear regression model where NIBUT and minimum central and inferior OST were identified as significant predictor variables.



There is strong evidence for significant interactions between corneal sensitivity, NIBUT, OST, and blink frequency, emphasizing that ocular surface conditions represent a possible important trigger for the initiation of a blink. However, the mechanisms involved in the initiation of a blink are complex, with local ocular sensory input as only one trigger, along with other external influences and internal factors under cortical control.
*PhD, MSc, MCOptom†PhD, MSc, FAAO‡PhD§PhD, MCOptom∥MBA, PhD, FCOptom, FAAOSchool of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom (DSN, HP, JA, CP, PJM); Institute of Optometry, University of Applied Sciences (FHNW), Olten, Switzerland (DSN); Dr. Heiko Pult-Optometry and Vision Research, Weinheim, Germany (HP); Cardiff Institute of Tissue Engineering and Repair, Cardiff, United Kingdom (JA); Spectrum Thea Pharamaceuticals Ltd., Newcastle under Lyme, United Kingdom (CP); and School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada (PJM).
Daniela Sonja
DS
Nosch
Heiko
H
Pult
Julie
J
Albon
Christine
C
Purslow
Paul John
PJ
Murphy
D000328:Adult; D001767:Blinking / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology; D015331:Cohort Studies; D003315:Cornea / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D010781:Photography; D012677:Sensation / Q000502:physiology*; D013499:Surface Properties; D011795:Surveys and Questionnaires; D013666:Tears / Q000737:chemistry*; D014787:Vision Tests; D055815:Young Adult