Evaluation of surgically induced astigmatism after coaxial phacoemulsification through 1.8 mm microincision and standard phacoemulsification through 2.75 mm incision.

UNLABELLED: Improvements in technology connected with cataract surgery have made it possible to decrease significantly the size of corneal incision created during phacoemulsification. Recently, coaxial phacoemulsification through a 1.8 mm microincision (C-MICS) has been introduced. This technique is perceived as the next step in development of phacoemulsification. PURPOSE: To compare surgically induced astigmatism (SIA) after coaxial 1.8 mm microincision cataract surgery (C-MICS) and standard phacoemulsification through 2.75 mm incision, calculated with three mathematical methods. MATERIAL AND METHODS: A consecutive, prospective series of 55 eyes of 55 patients who underwent uneventful C-MICS with foldable IOL implantation using 1.8 mm temporal clear corneal incision were included in group 1. Reference group (group 2) included 55 eyes of 55 patients who underwent uneventful phacoemulsification through 2.75 mm temporal clear corneal incision with a foldable IOL implantation. SIA was calculated using three methods. RESULTS: All patients had uneventful surgery and were examined before the surgery and one month postoperatively. There was a significant postoperative increase in corrected distance visual acuity in both groups (p < 0.01), and the visual outcomes in both groups were similar (p > 0.05). In vector analysis, mean SIA was 0.42 +/- 0.30 in group 1 and 0.77 +/- 0.55 in group 2. In vector decomposition, the mean SIA (C90) in group 1 was 0.24 +/- 0.29 and 0.49 +/- 0.54 in group 2 (p < 0.05). In Naeser's polar values method, deltaKP-0 was -0.06 +/- 0.43 in group 1 and -0.21 +/- 0.84 in group 2 (p > 0.05). CONCLUSIONS: 1.8 mm coaxial MICS induces a significantly smaller value of SIA than standard 2.75 mm phacoemulsification.