Purpose/background: To maximize recovery after neurologic injury, physicians use therapeutic hypothermia of 90°F to 93°F (32.2-33.9°C). Temperatures below this are avoided because of increased side effects. The extent to which the retina is cooled during routine vitreous surgery is unknown. This study seeks to describe the temperature changes of the vitreous and retinal surface during vitreous surgery.
Methods: In this prospective study of 6 patients undergoing vitrectomy, a 23-gauge thermoprobe was used to measure intraocular temperatures before, during, and after vitrectomy.
Results: Before vitrectomy, the mean midvitreous temperature was 93.1°F (33.9°C) and retinal temperature was 94.7°F to 95.4°F (34.8-35.2°C). During vitrectomy, the mean midvitreous cavity temperature was 76.9°F (24.9°C) and retinal temperature was 83.2°F to 85.1°F (28.4-29.5°C). After completion of vitrectomy and with a closed infusion line, the mean midvitreous cavity temperature was 87.0°F (30.6°C) and retinal temperature was 90.1°F to 90.9°F (32.3-32.7°C). These changes in temperature before, during, and after vitrectomy were found to be statistically significant.
Conclusion: During routine vitreous surgery, the vitreous cavity and retina are cooled to much lower temperatures than those used in therapeutic hypothermia. Rapid rewarming occurs within the eye once the infusion line is closed.