Accuracy of common IOL power formulas in 611 eyes based on axial length and corneal power ranges

Abstract

AimsTo provide clinical guidance on the use of intraocular lens (IOL) power calculation formulas according to the biometric parameters.Methods611 eyes that underwent cataract surgery were retrospectively analysed in subgroups according to the axial length (AL) and corneal power (K). The predicted residual refractive error was calculated and compared to evaluate the accuracy of the following formulas: Haigis, Hoffer Q, Holladay 1 and SRK/T. Furthermore, the percentages of eyes with ≤±0.25, ≤±0.5 and 1 dioptres (D) of the prediction error were recorded.ResultsThe Haigis formula showed the highest percentage of cases with ≤0.5 D in eyes with a short AL and steep K (90%), average AL and steep cornea (73.2%) but also in long eyes with a flat and average K (65% and 72.7%, respectively). The Hoffer Q formula delivered the lowest median absolute error (MedAE) in short eyes with an average K (0.30 D) and Holladay 1 in short eyes with a steep K (Holladay 1 0.24 D). SRK/T presented the highest percentage of cases with ≤0.5 D in average long eyes with a flat and average K (80.5% and 68.1%, respectively) and the lowest MedAE in long eyes with an average K (0.29 D).ConclusionOverall, the Haigis formula shows accurate results in most subgroups. However, attention must be paid to the axial eye length as well as the corneal power when choosing the appropriate formula to calculate an IOL power, especially in eyes with an unusual biometry.

Accuracy of intraocular lens power formulas for eyes with scleral-sutured intraocular lenses in congenital ectopia lentis

“…21 However, the percentage of PE within ±0.50 D was reported to reduce by 75% in long eyes and by 55% to 70% in eyes combined with a long AL and flat K, which indicates that long eyes and flat corneal curvatures in CEL may partly contribute to the inaccuracy of the IOL power calculations in our study. 31,32 In this study, the MAE of different formulas ranged from 0.63 to 0.75 D, greater than in normal cataract surgery. 27 Similarly, MAE were found to be more than 0.70 D with a flanged intrascleral IOL fixation, suggesting that, in cases where IOLs that were not implanted in the capsular bag, the accuracy of these formulas could be compromised.…”

Refractive prediction by various intraocular lens formulas using optical biometry and effect of ocular parameters on their accuracy

“…Although IOL power calculation began as an optical approach using theoretical formulas, the majority of methods used in clinical practice over the past 25 years are based on empirical methods that have used “fudged” formulas to compensate for the unknowns in the system. [ 8 9 ] However, the advent of better diagnostic equipment and ever-improving surgical techniques have decreased the number of unknowns, and optical methods now hold sway in IOL power calculation. For comparison, the mean numerical prediction error using the latest generation IOL power calculation formula (Olsen 2007) on the same dataset was found to be 0.00 ± 0.58D with a mean absolute error of 0.47D.…”

Long-term incidence of posterior capsular opacification in patients with non-infectious uveitis

“…Two experienced surgeons specializing in uveitis (KK and HT) performed all surgeries using the same surgical procedure and topical anesthesia. The surgical procedures were standardized 21 – 23 . A 2.5-mm, clear corneal/scleral incision was created at the 12 o’clock position.…”