Effects of local hypothermia on uveal blood flow and postoperative inflammation in vitrectomy.

Effects of local hypothermia on uveal blood flow and postoperative inflammation were evaluated in experimental vitrectomy in albino rabbits. Solutions used for intraocular perfusion were maintained at 9 degrees C, 22 degrees C or 37 degrees C. Following closed vitrectomy, the vitreous cavity was irrigated for 60 minutes. Temperatures at various sites and uveal blood flow were measured before and during the procedure. Aqueous protein concentrations were checked on postoperative days 1, 7 and 14. There was a larger decrease in temperature at the retina than at the choroid or the ciliary body. Blood flow at the ciliary body was reduced to 76.0% and that at the choroid to 77.0% of the preoperative level after 60 minutes of irrigation at 9 degrees C. The decrease was 91.0% and 88.3%, respectively, after 60 minutes of irrigation at 22 degrees C. Aqueous protein concentrations in the 9 degrees C and 22 degrees C groups were significantly lower than those in the 37 degrees C group on the first postoperative day in the eyes irrigated for 60 minutes. In the eyes irrigated for 30 minutes, however, no significant differences were seen. Local hypothermia during prolonged vitrectomy seems to decrease inflammation in the early postoperative stage.