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Blanka Golebiowski, Klaus Ehrmann, Jessica Chen, Brenda Truong, Fiona Stapleton; Liquid jet aesthesiometer repeatability and sex differences in corneal sensitivity.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):3239.
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© ARVO (1962-2015); The Authors (2016-present)
The Liquid Jet Aesthesiometer (LJA) is a novel, fast, non-invasive means of measuring corneal sensitivity. This study aimed to determine repeatability of this instrument and to use it to examine relationships between corneal sensitivity and sex, contact lens wear, subjective symptoms and tear function.
30 subjects aged 18-49 years (mean 23±6) with a healthy ocular surface completed the study: 17 males, 13 females, 16 soft contact lens wearers who did not wear lenses on day of measurement. Corneal sensitivity was measured using the LJA (Brien Holden Vision Institute, Sydney, Australia) on one randomly selected eye, by one examiner, on three occasions separated by a minimum of 30min, between 1-9pm. The LJA propels tiny droplets of sterile phosphate buffered saline (PBS) heated to 36°C; stimulu intensity is varied by changing the volume of PBS projected (0.3-4.75µL) during the 160ms stimulation time. Threshold to stimulation of the central cornea was determined by an automated double staircase; subjective response was indicated with a handheld button. Differences between repeat measurements were examined using repeated measures ANOVA, and coefficient of repeatability (CoR) was calculated from the within-subject standard deviation. Group differences were compared with repeated measures ANOVA test of between-subjects effects. Associations with ocular symptoms (Ocular Comfort Index) and tear stability (NITBUT, Keeler Tearscope) were examined using Pearson’s correlation.
Mean thresholds for the three repeats were 2.22±1.05µL, 2.48±1.11µL and 2.39±1.13µL, with no significant difference between the measurements. CoR was ±1.13µL and within-subject standard deviation was ±0.56µL. Corneal sensitivity was higher in females than males (threshold 1.73±0.70µL vs 2.85±0.93µL, p=0.001). There was no difference between contact lens wearers and non-wearers. Higher corneal sensitivity was weakly associated with poorer tear stability (r=0.13, p<0.001), but there was no association with symptoms.
The LJA is repeatable for same-day measurement of corneal sensitivity. The findings of higher corneal sensitivity in females and lack of association with subjective symptoms agrees with earlier reports using air-jet and nylon filament aesthesiometers. The relationship with tear stability requires further exploration. Future studies will examine effects of the LJA chemical and cold stimulus.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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