Keith Ong

Purpose

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.

Method

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.

Results

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).

Conclusion

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.