Abstract
Purpose :
<p style="margin: 0px; line-height: normal;">To examine the repeatability of central corneal sensitivity measurements using a liquid jet aesthesiometer (LJA, developed at the Brien Holden Vision Institute Ltd) using a cold stimulus, to explore the relationship between sensitivity to cold and warm stimuli and to explore the relationship between cold sensitivity and ocular comfort.</p>
Methods :
<p style="margin: 0px; line-height: normal;"> </p> 30 normal participants (14 females:16 males; 15 contact lens wearers) aged 18-40 years (mean 23.3±1.8) were recruited. Corneal sensitivity was measured four times with the LJA, once using a stimulus at 36°C (warm) and three times at 15°C (cold). Measurements were taken on one eye, 30 minutes apart over 2.5 hours on the same day, at least 4 hours after waking. Stimuli were droplets of phosphate buffered saline (PBS) where the volume was varied to change the stimulus intensity. Thresholds were generated using an automated double staircase paradigm. Ocular comfort symptoms were measured using the Ocular Comfort Index (OCI).
Results :
There were no statistically significant differences in cold thresholds between visits (Coefficient of Repeatability of ±0.322μL). The coefficient of variation for cold measurements was 59%. Lower thresholds were detected with cold compared with warm stimuli (p<0.0001; ANOVA). There was a significant negative association between cold threshold and discomfort in symptomatic individuals (OCI score >0) using the OCI questionnaire (r=-0.45, p=0.014).
Conclusions :
The LJA is moderately repeatable for same-day measurements of central corneal sensitivity using a cold stimulus. Threshold stimulus volume was lower for the cold stimuli than those delivered at eye temperature. The relationship between cold threshold and discomfort symptoms warrants further exploration.
This is a 2020 ARVO Annual Meeting abstract.