Comparison of noncontact infrared and re m o t e sensor thermometry in normal and dry eye

Infrared thermometry was employed by Alio and Padron (1) to study the temperature of the anterior segment of the eye in normal individuals between 15 and 80 years of age, who noted a decrease with advancing age. Efron et al (2) used a wide field color coded infrared imaging device and noted that following a blink, the geometric center of cornea showed cooling at a rate of 0.03±0.02 °C per second (p=0.001). Mori et al (3) measured corneal temperature by infrared thermography and noted a K value of dry eye 5.6±2.9 °C per second, which was significantly less than the control group (9.3±1.5 °C per second; p<0.05). They further noted a decline in temperature in patients with dry eye that was significantly less than in normal subjects. PU R P O S E. To evaluate the role of closed chamber infrared and remote sensor therm o m e t ry in normal and dry eye patients. ME T H O D S. The study was conducted on 51 dry eye cases (102 eyes), 26 men and 25 women aged 19 to 65 years (35.36±14.36), and 51 normal (102 eyes) ageand sex-matched control subjects. The criteria for dry eye were Schirm e r-1 (<10 mm/5 min), FTBUT (<10 sec), and lissamine green score (>2). The remote sensor and infrared therm o m e t ry was done in closed chamber around the eye in closed and open eye positions. RE S U LT S. In normal eyes, closed chamber infrared therm o m e t ry recorded temperature 34.77±0.37 °C in closed eye position and 35.02±0.39 °C in open eye position as compare d to 27.91±2.46 °C in closed eye position and 28.01±2.46 °C in open position with remote sensor t h e rm o m e t ry. The difference in temperature from closed to open position was 0.25±0.90 °C i n i n f r a red therm o m e t ry and 0.10±0.00 °C with remote sensor therm o m e t ry, which was statistically significant (p<0.0000). In dry eye, the infrared therm o m e t ry recorded 35.08±0.61 °C temperat u re in closed eye position and 35.53±0.63 °C in open eye position as compared to 27.41±2.48 °C in open and closed eye position with remote sensor therm o m e t ry. The difference in tempera t u re from closed to open eye position was 0.45±0.14 °C (p<0.0000) with infrared therm o me t ry as compared to no change 0.00±0.00 °C with remote sensor therm o m e t ry (p<0.0000). CO N C L U S I O N S. Remote sensor therm o m e t ry proved better for diagnosis of dry eye disease as it showed no change in temperature under closed chamber in closed and open position (p=0.0000). Infrared therm o m e t ry was better in recording the absolute temperature from any point on the eye. (Eur J Ophthalmol 2005; 15: 6 6 87 3 )