Abstract
Purpose:
Variable expected refractive errors are shown in various IOL power formulas when the corneal curvature is outside normal ranges. We tried to determine which formula may be less affected by evaluating comparative effect of corneal curvature on the predictability of intraocular lens power calculation using 5 different IOL power calculation formulas (SRK/T, HofferQ(H/Q), Master SRKT(M/T), Master HofferQ (M/Q), Master Holladay(M/Hol), Master Haigis(M/Ha))
Methods:
Medical records from 176 eyes were retrospectively reviewed. All patients had undergone uneventful phacoemulsification with IOL implantation from January 2010 to December 2011 at Seoul National University of Hospital. Preoperative axial length and keratometric power were measured by axial ultra sound((AXIS II PR, Quantel Medical, USA) and automated keratometer (KR-8900, Topcon, Japan) or IOL master( IOLMaster, Zeiss, Germany). IOL power was determined using SRK/T, H/Q, M/T, M/Q, M/Hol, and M/Ha formulas. Postoperative refractive errors 1 month after surgery were measured using automated refracto-keratometry. Mean absolute error (MAE) was defined as the average of the absolute value of the difference between postoperative and predicted spherical equivalent. MAE of 5 formulas were compared by using multiple regression analysis which was adjusted by axial length (SPSS ver. 18)
Results:
Multiple regression revealed that the change of corneal curvatures were significantly correlated with MAE in M/Hol formula(p=0.006, r=0.24) followed by in SRK/T formula( p =0.004, r=-0.207). H/Q, M/T, M/Q, and M/Ha formulas did not show significant correlation depending on the extreme K datas.
Conclusions:
Hoffer Q, Master SRKT or Master Haigis may be less affected by the outside normal range of corneal curvatures to expect IOL power.
Keywords: 567 intraocular lens •
677 refractive error development •
479 cornea: clinical science