摘要
AIM:To determine whether the different diameters of a specific intraocular lens(IOL)have significantly different optimized SRK/T A constants and whether these new A constants can improve refractive outcomes.METHODS:Data were collected prospectively from Jan.2011 to Dec.2012 on all patients undergoing routine cataract surgery at a district general hospital in the UK.Patients were divided into three groups according to the size of the Akreos AO MI60 IOL used.A constants for the SRK/T formula were optimized according to the size of the IOL.These optimized A constants were then used to select future refractive outcomes.RESULTS:A total of 2398 cataract operations were performed during the study period of which 1131 met the inclusion criteria.The three optimized A constants for the different sized IOLs were 118.98,119.13,119.32.The difference between them was highly significant(P≤0.0001).Two optimized A constants for three sizes of IOL led to an improvement in refractive outcomes(from 93.4%to 94.6%of refractive outcomes within 1.00 D of predicted spherical equivalent).The optimized A constant for the largest IOL was based on a small number of cases and was not used.CONCLUSION:Optimizing the A constant for the three distinct sizes of the Bausch&Lomb Akreos MI60 lens lead to three significantly different A constants.In our practice,using two different optimized A constants for three different sized IOLs give the least refractive error,however,using three optimized A constants may give better results with a larger dataset.
