Abstract
Abstract: :
Purpose: The corneal as well as the corneoscleral incision is considered to be standard in cataract surgery. However, both incision–techniques point out advantages and disadvantages. We investigated, if the way performing the incisions has different effects on the corneal wavefront especially on higher order aberrations. Methods: Each of 26 patients (6 men, 20 women), aged between 62 and 85 years (average 74.9 years), received a standard phakoemulsification by performing a corneal incision (2.9 – 3.2 mm, av = 3.12 ± 0.12) on the right eye and a corneoscleral incision (2.9 – 4.0 mm, av = 3.21± 0.2) on the left eye. The corneal surface was preoperatively investigated by using the Corneal wavefront instrument KeratronScout, (Schwind Company, Germany), as well as by the normal topography Keratometer (Technomed–Company, Germany). After at least 6 weeks the same parameters were measured again. Results: The following data were measured pre– and post–operatively: (min – max; av ± SD) Group 1 corneal incision: RMS: 0.1–3.13; 0.98 ± 0.53; (–0.71 – 1.89; 1.15 ± 0.51) µm Z(2.0)=Defocus: –6.42–15.10;3.64 ± 6.20; (–1.31–5.69; 1.83±1.66) µm Z(2±2)=Astigm.: 0.07–2.11;0.87 ± 0.53; (0.15 – 2.84; 1.14 ± 0.69) µm Z(3±1)=Coma: 0.04–1.12; 0.54 ± 0.28; (0.09–1.32 ; 0.54 ± 0.30) µm Z(3±3)=Trefoil: 0.07–0.91; 0.35 ± 0.22; (0.13– 1.23; 0.64 ± 0.33) µm Z(4.0)=Sph Abe: –0.07–1.03; 0.43 ± 0.23; (0.14–0.91; 0.40 ± 0.19) µm Group 2 corneoscleral incision: RMS: 0.44–1.89;0.96 ± 0.35; (0.53 – 1.86; 0.96 ± 0.31) µm Z(2.0)=Defocus: –7.28–17.60;3.72 ± 6.52; (–1.48– 4.41;1.59±1.38) µm Z(2±2)=Astigm: 0.2 –2.43; 0.85 ± 0.57; (0.08 – 3.13; 1.14 ± 0.70) µm Z(3±1)=Coma: 0.03 – 1.0; 0.5 ± 0.28; (0.10 – 1.00; 0.50 ± 0.24) µm Z(3±3)=Trefoil: 0.05–0.86; 0.36 ± 0.20; (0.02 – 1.21; 0.44 ±0.27) µm Z(4.0)=Sph Aber:–0.01–0.68; 0.43 ± 0.18; (0.01– 1.03; 0.42 ± 0.22) µm The statistic analysis of the pre– and postoperative data within the same group indicated significant differences (p < 0.05) in group 1 for Z(3±3)=Trefoil and in group 2 for Z(2±2)=Astigmatism. Comparing the postoperative data of the corneal and the corneoscleral incision, there was only a significant difference (p < 0.05) for Z(3±3)=Trefoil. Conclusions: In accordance to the induced higher order aberrations both surgical techniques can be seen equivalent.
Keywords: refractive surgery: corneal topography • refractive surgery: LASIK • refractive surgery: optical quality