Biaxial microincision versus coaxial small-incision clear cornea cataract surgery

To compare clinical outcomes of biaxial microincision (1.5 mm) and coaxial small-incision (2.75 mm) clear cornea cataract surgery.

Randomized controlled clinical trial.

Seventy eyes of 70 patients were examined at a German university eye hospital.

The 70 patients (70 eyes) were assigned randomly (1:1) to a biaxial or conventional coaxial incision group. Both groups underwent phacoemulsification using pulsed ultrasound energy with variable duty cycles, followed by microincision intraocular lens implantation.

Best-corrected visual acuity (BCVA), astigmatism, laser flare photometry value, effective phacoemulsification time (EPT), and endothelial cell count were evaluated.

The treatment groups did not differ in baseline characteristics (median BCVA of 20/40 preoperatively in both groups, P = 0.97). On postoperative day 1, BCVA was better in the biaxial group than in the coaxial group (20/25 vs. 20/33, P = 0.018). Eight weeks after surgery, median BCVAs were 20/20 in the biaxial group and 20/25 in the coaxial group (P = 0.015). Median changes in astigmatism were -0.15 diopters (D) in the biaxial group and -0.31 D in the coaxial group. Neither clinically relevant nor statistically significant differences were found in laser flare photometry values. Effective phacoemulsification time was >3 seconds in only 34% of biaxial procedures, versus 68% of coaxial procedures (P = 0.013). At 8 weeks after surgery, endothelial cell counts were decreased similarly in the biaxial (14.5%) and coaxial (14.1%) groups (P = 0.408).

With the biaxial microincision technique, EPT is shorter and BCVA improves more rapidly, with no difference in astigmatism, laser flare photometry results, or endothelial cell count relative to the coaxial small-incision technique for phacoemulsification.