[The clinical investigation of dynamic changes of corneal astigmatism and visual quality for patients after phacoemulsification surgery through different incision and implantation of different designed intraocular lens].

OBJECTIVE: To compare the corneal astigmatism and wavefront aberration differences of patients with cataract coexisting corneal astigmatism after phacoemulsification surgery through traditional superior clear corneal incision or phacoemulsification surgery through clear corneal incision guided by corneal topography and implantation of different spherical aberration intraocular lenses (IOL).

METHODS: In a prospective randomized sample controlled clinical trial, 90 patients (90 eyes) with age-related cataract and corneal astigmatism were randomly divided into 3 groups: (Group A) traditional superior corneal incision phacoemulsification surgery and AcrySof SN60AT IOL implantation, (Group B) corneal topography guiding incision phacoemulsification surgery and AcrySof SN60AT IOL implantation and (Group C) corneal topography guiding incision phacoemulsification surgery and AcrySof SN60WF IOL implantation. Corneal topography tests were performed at 1 week, 1 month, 3 months and 6 months postoperatively. The Wavefront aberration was measured using a custom built Tscherning wavefront sensor-ALLEGRETTO WAVE Analyze at 90 days postoperatively. Third-, 4th-, 5th-, total and higher-order aberration (HOA) root-mean-square (RMS), spherical aberration and coma aberration were compared at virtual pupil diameters of 6 mm postoperatively. Statistical analyses were performed using the analysis of chi square test, repeated measurement data analysis of variance, one-way analysis of variance (ANOVA), and multiple comparisons Students-Newman-Keuls test.

RESULTS: Corneal topography tests indicated that no significant difference for corneal astigmatism was found between these three groups preoperatively (F = 0.08, P > 0.05). The corneal astigmatism was decomposed into J(0), J(45) and P with a Vector-based method, and statistically analyzed. When compared with Group B and GroupC, Group A had higher values of corneal J(0) (F = 9.54, P < 0.01) and P (F = 18.69, P < 0.01). For corneal J(0) and P, no significant difference was found between Group B and Group C (P > 0.05). However groups and times had interactions (F = 13.45, 50.22, P < 0.01, respectively). For astigmatic vectors, there were statistical significances between different times in 3 groups (F = 74.33, 92.11, P < 0.01, respectively). Wavefront aberration test results indicated that the mean values of RMSg (root mean square of general aberration), coma aberration, RMSh, RMS(3), RMS(5) and RMS(6) of Group A were obviously higher than that of Group B and C (F = 93.40, 471.94, 176.95, 216.99, 44.37, 37.19, P < 0.01, respectively). And the values of RMS(4) and spherical aberration in Group A were significantly higher than that in Group C (q = 25.30, 26.23, P < 0.01, respectively). No statistically significant was found between Group A and Group B of RMS(4) and spherical aberration (q = 0.57, 2.34, P > 0.05, respectively). The values of RMS(4), RMSh, RMSg and spherical aberration in Group B were statistically significantly higher than that in Group C (q = 24.73, 7.90, 6.41, 23.89, P < 0.01, respectively).

CONCLUSIONS: Corneal topography guiding incision phacoemulsification surgery and the implantation of negative spherical aberration IOL is a more favorable solution for cataract patients coexisting corneal astigmatism, which can correct the corneal astigmatism, decrease the spherical aberration, high-order aberration and general aberration of pseudophakic eyes and therefore improve the visual quality of patients.