Efeito da posição do bisel da caneta de facoemulsificação no endotélio corneano

Purpose: To compare the extent of corneal endothelial (CE) cell loss changes in two groups of eyes submitted to phacoemulsification, with the conventional bevel-up tip position in one eye and with the bevel-down tip position in the fellow eye. Methods: This prospective clinical trial comprised 25 patients with bilateral cataracts subjected to lens removal by phacoemulsification with the conventional bevel-up tip position (GI) in one eye and with the bevel-down tip position (GII) in the fellow eye. The nuclei were graded clinically on the basis of hardness. The endothelial cell count (ECC) was evaluated preoperatively and 1, 3 and 6 months postoperatively. Total surgical time, effective ultrasound time and complications were also compared between the groups. Statistical analysis was performed by the Tukey Studentized Range test, with repeated measures for the selected periods. For the other parameters a paired t test was used. Data are presented as mean ± SD, with the level of significance set at p<0.05. Results: The mean effective ultrasound time was 8.08 ± 6.75 seconds in group I and 7.00 ± 5.75 seconds in GII (P=0.1792) and total surgical time was 10.01 ± 2.46 minutes in GI and 9.86 ± 2.17 minutes in GII (p=0.6267), respectively. The paired t test revealed no statistical differences between the groups. Complications were also similar between the groups. Mean endothelial cell count loss was 6.9% in GI and 2.8% in GII at one month; 6.9% in GI and 3.6% in GII at three months and 11.9% in GI and 7.6% in GII at six months postoperatively. Comparison of endothelial cell count (ECC) showed a statistically significant difference between the groups during the postoperative period. Conclusion: The conventional bevel-up tip position has a negative effect on corneal endothelial cells compared with the bevel-down position. Since the results of other surgical parameters were similar, the bevel-down tip position should be considered as an option in non-complicated phacoemulsification.