To determine whether the discrepancy between autorefraction (AR) and subjective refraction (SR) should be considered when selecting IOL power for cataract surgery in eyes that have previously undergone LASIK for myopia.
A retrospective case analysis was conducted on 9 consecutive eyes of 6 patients with prior history of LASIK for myopia and underwent phacoemulsification with implantation of Alcon SN60WF PC IOL. The difference between AR and SR was compared post-cataract surgery, and the predictability of SRK-T and Haigis IOL power calculation formulae were evaluated by comparing the post-cataract surgery SR and AR to the refraction predicted by the formulae.
Post-cataract surgery AR was significantly more minus than SR (spherical equivalent [SE], 0.61±0.47D, p<0.05). The amount of LASIK correction did not correlate with the difference between post-cataract surgery SR and AR (r=0.61). The difference between predicted refraction and post-cataract surgery AR was significantly less (p<0.05) when calculated with Haigis (-0.09±0.52D) in comparison to SRK-T (-0.79±0.52D). There was also a significant difference (p<0.05) between predicted refractions and post-cataract surgery SR when calculated with Haigis (-0.70±0.45D) in comparison to SRK-T (-1.41±0.62D).
AR yields a more minus refraction in comparison to SR following LASIK. The predicted post-cataract surgery refraction was more accurate with Haigis in comparison to SRK-T in this cohort of post-LASIK patients. Both formulae were more accurate in predicting post-cataract surgery AR than SR. Hence, evaluating the difference between AR and SR may be a useful guide when selecting the IOL power to achieve target SR.