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IOL power calculation using the Kane formula in comparison to existing methods in the elderly population

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First Author: O.Reitblat ISRAEL

Co Author(s):    L. Chou   H. Gali   I. Bahar   R. Weinreb   N. Afshari   R. Sella     

Abstract Details

Purpose:

To assess the accuracy of the new Kane formula for intraocular lens (IOL) power calculation in comparison to established formulas in patients 75 years old and above.

Setting:

A retrospective case-series performed at the Shiley Eye Institute, University of California San Diego, USA.

Methods:

Data from patients ≥75 years old, having uneventful cataract surgery with SN60WF IOL implantation between January 2015 and May 2018, were retrospectively obtained. The first operated eyes of patients with final best-corrected visual acuity ≥20/40 and axial length 22-26 mm were included. Prediction errors of refractive outcome were calculated for Kane, Barrett Universal II, Hoffer Q, Holladay 1, SRK/T and Haigis formulas. Median absolute error (MedAE) and the percentage of eyes within ±0.50D and ±1.00D of each formula were compared. A corresponding subgroup analysis based on age (75-84 and ≥85 years old) was performed.

Results:

The study included 90 patients. The Kane and Barrett Universal II formulas resulted in the highest percentage of eyes with prediction errors within ±0.50D (both 72%), and were found significantly better than Hoffer Q, Holladay 1 and SRK/T (P = 0.001). Rates of predictability within 1.00D ranged between 87% and 92% with no significant differences between formulas. No statistically significant difference was seen between formulas in the MedAE. These tendencies remained consistent in both age groups separately, however, subgroup analysis showed a trend towards better outcomes for all formulas in the younger age group than in patients ≥85 years old.

Conclusions:

This is the first study evaluating the Kane formula in the exclusively elderly population. The Kane formula was found equal to the Barrett Universal II and superior than Hoffer Q, Holladay 1 and SRK/T formulas for IOL power calculation in elderly patients. Very elderly patients undergoing cataract surgery may be prone to reduced refractive precision using all formulas.

Financial Disclosure:

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