Abstract
Abstract: :
Purpose: Povidone iodine (PI) is a well-accepted means of pre-operative disinfectant and has been widely used for many years. Corneal endothelium may be exposed to PI through inadvertent leakage into the anterior chamber intra-operatively or during pre-operative preparation of an eye with a traumatic laceration. Thus, this study explores the effects of PI on the corneal endothelium by examining the change in the number of corneal endothelial cells following exposure to 1%, 2%, and 5% concentrations of PI in a porcine model. Method: A total of 35 porcine corneas were examined and divided into four groups. Seven porcine corneas (group A) were measured prior to and following a 1 minute exposure to 1% PI solution using specular microscopy. Ten porcine corneas (group B) were examined using 2% PI solution. A 5% solution was used to examine ten porcine corneas (group C). Eight eyes were used as controls (group D), in which corneas were measured and then recounted following a 1 minute exposure to BSS. Results: The mean corneal endothelial cell count in group A was 3870 +/- 387 cells/mm2 prior to exposure to 1% PI and 3604 +/- 433 cells/mm2 afterward. There was no significant change in these groups (p = 0.10). The mean counts for group B were 3634 +/- 293 cells/mm2 prior and 3115 +/- 328 after exposure. This did represent a significant difference (p<.0001). In group C, the endothelial count was 3582 +/- 351 cells/mm2 before and 2948 +/- 376 cells/mm2 following 5% PI solution. This also demonstrated significant change (p<.0001). In the control group D, the endothelial cell count was 3639 +/- 220 cells/mm2 prior and 3741 +/- 176 cells/mm2 after soaking in BSS. There was no significant difference in this group (p = 0.16). When comparing groups A, B, and C to the control group D prior to exposure to the PI solution, no difference was found. Following exposure to the respective solutions, there was no significant difference found in group A, however, a significant difference was found when comparing groups B and C to the control. Conclusion: The results of our study suggest that concentrations of 2% and 5% PI were toxic to the endothelium of porcine eyes after one minute of exposure. Interestingly, there was no significant change in the number of endothelial cells using the 1% solution (group A) when compared to the same eyes prior to exposure. This data may suggest that if an inadvertent drop (.05 ml) of half-strength PI should escape into the anterior chamber intra-operatively (0.30 ml in volume creating 0.8 % concentration), that this amount may not be toxic to endothelial cells. However, concentrations just greater to this amount potentially could cause harm.