Experimental study of intraocular temperature distribution in the rabbit under various environmental conditions

Purpose To study ocular temperature distribution in the rabbit in dependence on ambient temperature in experiment. Methods To measure ocular temperature a thermoelectric device was developed; the latter consisted of a temperature recording microprocessor module, polytetrafluoroethylene microprobes (diameter – 0.6 mm) with thermocouple sensors, computer software for visualization and registration of temperature parameters in real time. The device allows measurements in the temperature range from 10 to 120°C with ± 0.05°C accuracy. The experiment was conducted on 21 rabbits (42 eyes) which were divided into 3 groups. Group 1 consisted of 11 rabbits (22 eyes) ocular temperature measurements of which were made at ambient temperature with the range of 23–24.5°C while Group 2 and 3 consisted of 5 rabbits (10 eyes) each with ambient temperatures with the range of 14.5–15.5°C and 30–32°C, respectively. Results The lowest temperature was noted on the outer corneal surface, and then it increased gradually in the inner segments of the eye and reached its maximum in the retina and subtenon space. A temperature gradient between the outer corneal surface and the retina was 3.23, 4.68 and 3.85°C in Group I, II and III, respectively. No significant difference between temperatures in the left and right eyes of the experimental animals was observed. Data obtained in this study show the lowest correlation between temperatures of the anterior corneal surface and retina. The high correlation was observed between temperatures of inferior conjunctival fornix and retina. Conclusions Raising and lowering of the ambient temperature increases the temperature gradient between the external and internal structures of the rabbit eye.