Corneal spherical aberration and its impact on choosing an intraocular lens for cataract surgery

Purpose: To analyze the post operative results of targeting zero spherical aberration by selecting the best-fit aspheric intraocular lens (IOL), based on preoperative corneal spherical aberration of patients with phacoemulsification surgery. Setting: AlHokama Eye Specialist Center, Riyadh, Saudi Arabia. Period: From the 1st of October 2012 until the 10th of April 2013. Methods: Fifty-three eyes, were subjected to phacoemulsification cataract surgery and divided into two groups, 34 eyes were implanted with aspheric IOLs based on their corneal spherical aberration targeting post operative zero total spherical aberration, whereas 19 eyes were implanted with neutral aspheric IOLs regardless of their corneal spherical aberrations (CSAs). As a pre and post routine examination, patients underwent: slit lamp testing, intraocular pressure (IOP) measuring, fundus examination, best spectacle corrected visual acuity (BSCVA), manifest refraction, pupillometry, axial length, contrast sensitivity, and corneal aberration measurement using Pentacam HR (OCULUS, Germany) at the 6-mm optical zone. Post operatively, visual function questionnaire (VF-14) was asked to all patients. Results: Fifty-three eyes of 45 patients, whose age ranged from 45 to 90 years old, were available for analysis, the selected group was implanted with: Tecnis ZA9003 or ZCB00 (Abbott Medical Optics) IOLs in 17 eyes with corneal spherical aberration of more than 0.27 mu m, AcrySof IQ SN60WF (Alcon Laboratories Inc.) IOLs were implanted in 4 eyes with CSA = (0.2-0.27) mu m, and Rayner 970C, 920H or 620H IOLs with spherical aberration (SA) = 0 in 13 eyes with CSA less than 0.20 mu m. The other group of 19 eyes was implanted with aspheric IOLs that have zero spherical aberration (Rayner 970C or 920H) regardless of their CSA. Root mean square (RMS) of total corneal aberration positively correlates to the pupil diameter (P = 0.0031, r = 0.3989). A low negative correlation was found between the corneal spherical aberration of the fourth ordered (Z40) and the axial length (r = -0.2009, P = 0.1492). There was no significant difference between the selected and non-selected group in contrast sensitivity, best spectacle corrected visual acuity, and visual satisfaction (P = 0.5316, P = 0.3919, P = 0.7667). Conclusion: Customized selection of aspheric IOLs based on the eyes' corneal spherical aberration has no significant importance comparing their results with the non-selected group.