To evaluate the effect of power, vacuum, and flow rate on endothelial cell loss after phacoemulsification.
Labbafinejad Medical Center Medical Center, Tehran, Iran.
In a prospective randomized clinical trial, phacoemulsification was performed in 2 groups (high vacuum and low vacuum) with 3+ nuclear sclerosis. The stop-and-chop technique was used with the Sovereign machine. Machine parameters during the chop stage were vacuum 400 mm Hg in the high-vacuum group and 200 mm Hg in the low-vacuum group and flow rate, 40 cc/min and 20 cc/min, respectively. Endothelial cell density preoperatively before and 1, 6, and 12 weeks postoperatively were compared.
Each group comprised 30 eyes. The mean US power was 9.2% ± 4.3% (SD) in the low-vacuum group and 13.1% ± 4.6% in the high-vacuum group (P = .001) and the mean phaco time, 1.28 ± 1.0 minutes and 0.88 ± 0.6 minutes, respectively (P = .04). Total US energy and total fluid consumed were similar between groups. After 12 weeks, the mean endothelial cell loss was 9.0% ± 4.0% in the low-vacuum group and 9.6% ± 4.6% in the high-vacuum group (P = .6). There was a relationship between total US energy and endothelial loss (P<.001); however, total fluid volume was not a significant predictor (P = .19).
Vacuum level did not have a significant effect on total US energy or total fluid consumed during phacoemulsification. There was a strong relationship between total US energy and endothelial cell loss but not between total infused fluid and endothelial cell loss.