Journal of Clinical and Experimental Ophthalmology
Open Access
ISSN: 2155-9570
ISSN: 2155-9570
John C Merriam
Tanzania
Research Article
A Method to Improve the Accuracy of Optimized A-Constant for IOL Calculation Formulas
Author(s): Lei Zheng and John C MerriamLei Zheng and John C Merriam
Objective: To achieve more accurate IOL calculation results using multiple A-constants for SRK/T formula. Methods: This is a retrospective clinical study. The study includes 650 cases of phacoemulsification with an Acrysof SN60WF IOL (Alcon, TX). The study excluded eyes that had corneal refractive surgery, eyes with any condition that precluded accurate and consistent keratometry. The study used the average of 5 valid measurements of axial length (AL) and corneal curvature using IOLMaster (Carl Zeiss Meditec, Inc. Germany) prior to surgery and manifest refraction measured at least 3 months after surgery. Patients were divided into 7 groups based on AL from less than 22 mm to greater than 27 mm. The average A-constant with standard deviation was calculated in each group, and these groups were compared to each other using independent two-sample t.. View More»
DOI:
10.4172/2155-9570.1000765