Accuracy of intraocular lens power calculation methods when targeting low myopia in monovision

J Cataract Refract Surg. 2020 Jun;46(6):862-866. doi: 10.1097/j.jcrs.0000000000000187.


Purpose: To investigate the accuracy of IOL power calculation methods for refractive targets of myopia compared with emmetropia.

Setting: Lions Eye Institute, Perth, Australia.

Design: Retrospective analysis.

Methods: Patients undergoing bilateral, sequential cataract surgery with a plan of modest monovision were analyzed. Target refraction was plano (distance eye) and -1.25 diopters (D) (near eye). Prediction error was determined by comparing the actual postoperative refraction with the predicted postoperative refraction, calculated by the Barrett Universal II (BUII), Hill-RBF version 2.0 (Hill-RBF 2.0), Haigis, Holladay 1, SRK/T, and Hoffer Q formulas. The dataset was divided into distance and near eye subgroups. Mean and median absolute error and percentage of eyes within ±0.25, ±0.50, ±0.75, and ±1.00 D of refractive target were compared.

Results: The study included 88 consecutive patients. There was a consistent trend for lower refractive accuracy in the near eyes. BUII and Hill-RBF 2.0 were the most accurate overall and least affected by this phenomenon, with 1 (1.1%) and 4 (4.6%) fewer eyes, respectively, in the near subgroup achieving ±0.50 D of target. Haigis and SRK/T were most affected, with 14 (15.9%) and 11 (12.5%) fewer near eyes achieving ±0.50 D of target (P < .05). Holladay 1 and Hoffer Q occupied the middle ground, with 6 (6.8%) and 9 (10.2%) fewer near eyes achieving ±0.50 D of target.

Conclusions: IOL-power calculation formulas appear to be less accurate when targeting myopia compared with emmetropia. BUII and Hill-RBF 2.0 represented good options when planning pseudophakic monovision as they were least affected by this phenomenon and can be used for both distance and near eyes.

MeSH terms

  • Australia
  • Biometry
  • Humans
  • Lenses, Intraocular*
  • Myopia* / surgery
  • Optics and Photonics
  • Refraction, Ocular
  • Retrospective Studies
  • Vision, Monocular