1. Corneal shape and corneal aberrations after MicroIncision Cataract Surgery (MICS) NOCHEZ Y, BUREL B, MAJZOUB S, PISELLA PJ Yannick.nochez@free.fr C.H.U. Bretonneau, Tours, France No financial disclosure

2.  The aim of our study was to evaluate corneal structural changes after MICS : Corneal topography Corneal Higher-Order Aberrations (HOA) Surgically Induced Astigmatism (SIA) PURPOSE

3.  Prospective study.  30 eyes of 20 patients with senile cataract underwent MICS through 1.8 mm clear corneal incision.  An aspherical single-piece lens Acrismart 36A ® (Carl Zeiss) was implanted. METHODS

4. Surgical Method  Topical anesthesia with tetracaine was used  Pupils were dilated with neosynephrine and tropicamide. 1,8 mm clear corneal incision was made on the 10th meridian with a pre calibrated trapezoid knife.  We used Provisc visco elastic (Alcon®)  The surgery machine used was the Stellaris (Baush and Lomb ®) Phaco emulsification was performed with a 0,95 mm 30 degres angled tip using a continuous ultrasound setting.

5. Pre and Post operative parameters :  Corneal Topography (Atlas 9000®, Carl Zeiss Meditec) Placido disk technology Axial and tangential curvature Keratometry We assess corneal HOA with corneal wavefront analysis  These parameters were collected before surgery and 3 months after.

6.  No significant difference on keratometry on the steep and flat axes was noted (p>0.05). RESULTS  AcrySmart 36A IOL was inserted through 1.8 mm incision with minimal or no difficulty Gentle insertion, no tissue damage Easily unfolds into capsular bag Centres immediately Incision measurement at the end of surgery : 1.9mm in all cases

7. Surgical Induced Astigmatism  Alio et al (2005) noted 50 % of the eyes presenting a vectorial change > 1 D after 3 mm cataract surgery.  The mean surgical induced refractive astigmatic change, calculated using the vector analysis method was 0.54 ± 0.4 D. Vectorial change of refractive astigmatism was < 0,5 D Vectorial change between 0,5 and 1 D Vectorial change >1 D 60 % 30 % 10 %

8.  Corneal Higher-Order Aberrations don’t change before and after MICS (p>0,05)

9. Corneal HOAs  No significant changes between pre and postop HOAs values. Corneal HOA PreopPostopP value Astigmatism Z22 + Z2-2 Mean 0,0160,2930,301 SD0,981,14 Coma Z31 + Z3-1 Mean -0,091-0,1150,51 SD0,330,322 Trefoil Z33 + Z3-3 Mean -0,095-0,1710,09 SD0,3330,283 Spherical aberration Z40 Mean 0,2610,2640,77 SD0,0910,101

10. Corneal Spherical Aberration (SA)  Mean corneal SA = 0,26 µ +/- 0,1  Strong correlation between pre and post-operative SA. P < 0,001

11.  MICS appears to be a safe technique with no endothelial changes.  This technique seems to induce less corneal astigmatism.  MICS has low impact on all corneal aberrations, confirming Guirao et al results (IOVS 2004;45:4312-4319). DISCUSSION = Preop corneal SA Postop corneal SA

12.  Preoperative corneal aberrations measurement may be useful to predict total ocular spherical aberration using an aspherical lens. += CONCLUSION 0,25 µ-0,18 µ 0,07 µ ? 36 A