Postrefractive Cataract Surgery Outcomes Using Novel IOL Calculator
Purpose
To assess the efficacy of a novel post-refractive intraocular lens (IOL) calculator that calculates the required IOL power without need for historical data using data obtained from rotating Scheimpflug imaging.
Methods
This is a retrospective analysis of cataract surgery outcomes in eyes with prior history of photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK). Inclusion criteria: Eyes with prior history of refractive surgery that underwent cataract surgery at Walter Reed National Military Medical Center in 2013. Exclusion Criteria: Eyes with complications from cataract surgery that might limit post-operative refractions. 14 eyes were included, no eyes were excluded. IOL power calculations were performed using the novel calculator, Haigis-L, and ASCRS online calculator average. Post-operative refractive results were extrapolated and compared amongst the 3 calculators.
Results
Post-operative refractive results were extrapolated using the actual refractive outcomes and the difference in power between the actual IOL power implanted and the calculated IOL power for the 3 calculators. The predicted refraction mean absolute error (MAE) for the novel calculator was 0.31 D ± 0.32, as compared with 0.65 D ± 0.33 for Haigis-L, and 0.42 D ± 0.28 for the ASCRS calculator average. The MAE difference between the novel calculator and Haigis-L was statistically significant using a paired t test (p=0.005) while the difference between the novel calculator and the ASCRS calculator average was not significant (p=0.304).
Conclusion
While this was a small sample size, the novel calculator showed favorable results comparable to the common calculators currently in use. It is useful for both prior hyperopic and myopic refractive surgery and is quick and easy to perform using data readily obtainable from rotating Scheimpflug imaging.