The Accuracy of Intraocular Lens Power Calculation Formulas for Eyes of Axial Length Exceeding 25.0mm

Research Article

Austin J Surg. 2019; 6(24): 1227.

The Accuracy of Intraocular Lens Power Calculation Formulas for Eyes of Axial Length Exceeding 25.0mm

Stopyra W*

Ophthalmological Hospital MW med, Poland

*Corresponding author: Wiktor Stopyra, Ophthalmological Hospital MW med, Cracow, Poland

Received: September 19, 2019; Accepted: November 01, 2019; Published: November 08, 2019


Purpose: Comparison of intraocular lens power calculation formulas accuracy for eyeballs longer than 25.00mm.

Material and Methods: 70 patients (81 eyeballs) were examined, whose ocular axial length ranged between 25.01mm and 28.57mm. Preoperatively, the intraocular lens power for each patient was calculated using six different formulas (Holladay1, SRK/T, Hoffer Q, Holladay 2, Haigis and Barrett Universal II). The power of the implanted IOL was based on the Holladay 2 formula. Three months after cataract surgery, postoperative refraction was measured. Mean absolute error as a difference between postoperative and predicted spherical equivalences of refractive error was calculated.

Results: The Barrett Universal II formula achieved the lowest level of mean absolute error of 0.08 ± 0.08 D (p ‹ 0.001 for Barrett Universal II versus each of the other formulas). Further places were taken by the following formulas: Holladay 2 (0.13 ± 0.09 D), Haigis (0.17 ± 0.12 D), SRK/T (0.18 ± 0.13 D), Holladay 1 (0.20 ± 0.14 D), Hoffer Q (0.26 ± 0.15 D). P ‹ 0.001 for Holladay 2 versus Hoffer Q formula, for Haigis versus Hoffer Q and for SRK/T versus Hoffer Q. Additionally, correlation between absolute error and axial length was evaluated. It was observed, that absolute error had been associated with axial length when Holladay 1 or Barrett Universal II or Hoffer Q formula had been used.


1. The Barrett Universal II formula is recommended for intraocular lens power calculation for eyeballs with axial length longer than 25.0mm.

2. Holladay 2 formula seems to be satisfactory for these cases.

Keywords: Intraocular lens power calculation formula; Eyeball longer than 25.0mm; Barrett Universal II formula; Mean absolute error


It is generally accepted that most Intraocular Lens (IOL) power calculation formulas perform well for eyes of average Axial Length (AL) i.e. 22.0 – 25.0mm [1]. The choice of intraocular lens power calculation formulas must be very careful in the cases when an eyeball is longer than 25.0mm or shorter than 22.0mm [2-4]. There are many IOL power formulas. They form five generations – details in Table 1 [5].