Utilizing intraoperative aberrometry and digital eye tracking to develop a novel nomogram for manual astigmatic keratotomy to effectively decrease mild astigmatism during cataract surgery

PURPOSE: The purpose of the study is to develop a novel nomogram and validate with a retrospective comparative study for manual astigmatic keratotomy (MAK) with the assistance of intraoperative aberrometry (Optiwave Refractive Analysis [ORA]) and digital eye tracking (VERION) in mild astigmatic correction enhancement. SETTING: The study was conducted in Honolulu, Hawaii. DESIGN: This was a single-surgeon comparative study with retrospective data collection. METHODS: Sixty consecutive adult cataract surgery cases with regular astigmatism of 1.25 D or less were included for study from April 2016 to April 2017. VERION was used preoperatively in all cases. MAK was performed before phacoemulsification according to the surgeon's own nomogram. ORA then was utilized to obtain the axis and remaining cylinder power after phacoemulsification and intraocular lens implant implantation. MAK extension was performed for eyes with 1 D or more of remaining cylinder. Extensions were carried out slowly and slightly until the amount of cylinder was 1½ D or less under ORA. The mean degrees of extension plus the original MAK plan were calculated to develop the new nomogram. Sixty consecutive similar cases by the same surgeon using the surgeon's nomogram without using ORA/VERION for enhancement were reviewed from April 2015 to April 2016 for comparison. All patients included in this study signed the consent form. RESULTS: Using Alpins vector analysis for comparison, the proportion of patients with cylinder <0.5 D 3 months postoperatively was 87% in the ORA/VERION group compared to 70% in the non-ORA/VERION group (P < 0.05). Better than 20/25 best-corrected visual acuity was achieved more in the ORA/VERION group compared to non-ORA/VERION group. CONCLUSIONS: This novel nomogram developed by the surgeon may have better outcomes than the old surgeon's own nomogram. Further prospective control study is needed to validate the efficacy. If validated, those surgeons who do not have ORA/VERION can hopefully use this nomogram with greater success.