Abstract
Purpose :
To analyze the correlation between corneal surface temperature (CST) values, tear rate and ocular surface disease (OSD) signs and symptoms in Sjögren's Syndrome (SS) patients and healthy subjects.
Methods :
Eighty one volunteers were explored with the McMonnies questionnaire (MMQ) adapted for Spanish-speaking people, Schirmer test, TBUT, tear meniscus height (estimated by OCT), and corneal fluorescein staining (Oxford scale). 30 patients diagnosed of primary or secondary SS (51±11 years old; 27 women/3 men) and 30 without OSD (Control; 47±9 y; 21/7) were included; 21 were excluded (presence of OSD signs). Temperature at central cornea was measured from infrared video images (InfRec R300SR, Nippon Avionics) using dedicated software. CST values at 0.1s after a voluntary blink (TM) and along the interblink interval (IBI) were measured and used to calculate the slope of temperature reduction during the IBI. Room partial humidity (42%) and temperature (23°C) were kept constant
Results :
All clinical variables (Schirmer, TBUT, corneal staining, MMQ and tear meniscus height were significantly different in SS and control groups; p<0,001, all variables). A 2-phase CST profile was observed during the IBI in both groups: a fast temperature reduction during 1st s after eye opening (slope R1) followed by a slower CST decay (slope R2), reaching the minimum CST value (Tm) just before next blink. CST was significantly higher in SS than in controls subjects at TM (34,8±0,6°C vs 33,9±0,8 °C; SS vs controls; p〈0,001, t-test) and 2s after eye opening (34,2±0,7°C vs 33,6±0,8 °C; p=0,001), and slightly higher at Tm (33,6±0,7°C vs 33,2 ±0,9°C; p=0,078). R1 (-0,37±0,31 °C/s vs -0,26±0,2 °C/s; p=0.22) and R2 slopes (-0,09 ±0,07 °C/s vs -0,22 ±0,83; p=0.35) were slightly faster in SS than control. Pearson analysis showed no significant correlation between CST parameters and OSD signs/symptoms, except for the significant negative correlation between severity of corneal staining and Tm value (p=0,04) in SS patients, and between CST (both, TM and Tm) and age, both in SS (p=0.04) and control subjects (p=0.01).
Conclusions :
OST is reduced with age in control and SS patients. Besides a reduced tearing rate, SS eyes show higher CST and a greater ocular surface cooling between blinks, which would be responsible for an increased activation of cold thermoreceptors, thus generating eye dryness and discomfort sensations.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.