Effect of steep meridian clear corneal incisions in phacoemulsification

To evaluate the torque and flattening effect of steep meridian clear corneal incisions on cornea in phacoemulsification when posterior cornea surface measurements were considered.

Thirty-six eyes underwent cataract surgery with steep meridian clear corneal incisions. Before surgery and at 1 month and 3 months after surgery, corneal topography was measured with a rotating Scheimpflug camera. Both preoperative and postoperative corneal astigmatism were calculated in 2 ways: total corneal astigmatism and keratometric astigmatism. Polar analysis was used to evaluate the flattening and torque effect of steep meridian incisions on corneal astigmatism.

Total corneal astigmatism changed significantly after 3 months (p = 0.005) and univariate analysis revealed a significant change 0.25D ± 0.36 D in astigmatic polar value AKP(+45) of total corneal astigmatism (p = 0.047). A decrease in AKP(+0) was observed in both keratometric and total astigmatism at 1 and 3 months, although the decreases were not statistically significant (p = 0.394, p = 0.442, p = 0.602, p = 0.503, respectively).

Steep meridian incision performed on the preoperative steeper meridian of keratometric astigmatism may cause a significant torsional effect on total corneal astigmatism as well as reducing the astigmatism along the meridian.