Abstract
Abstract: :
Purpose: Several third generation IOL formulas are used to estimate the power for intraocular lens (IOL) implantation, but no studies have investigated the accuracy of these formulas in children. The current study compared the performance of 4 IOL formulas to determine which, if any, was most suitable for pediatric eyes. Methods: We retrospectively reviewed the final refractive outcome for 22 consecutive pediatric eyes that underwent cataract extraction with IOL implantation in children from age 4 months to 21 years (average age of 13 years) and met inclusion criteria. Preoperative measurements of Best Corrected Visual acuity (BCVA), axial length, anterior chamber depth, lens thickness, manifest or retinoscopic refraction, and keratometry were taken and entered into either the SRK-T, Hoffer Q, Holladay 1, or Holladay 2 IOL formulas. Each IOL was implanted using the same technique by the same surgeon (LT) and placed either in the bag (primary implantation) or sulcus (secondary implantation). Post-operative refractions were obtained a minimum of two months after implantation as a measure of final refraction. The error, defined as the difference between predicted post-operative refraction and actual post-operative refraction, was then compared between the four formulas using analysis of variance and Holladay Intraocular Lens Consultant© software. Results: The error ± SD in lens diopters (D) was 1.34 ± 1.84 D for the Holladay 2, 1.30 ± 1.83 D for the Holladay 1, 1.35 ± 1.86 D for the Hoffer Q, and 1.38 ± 1.96 D for the SRK-T formulas, respectively (p <.05 for all formulas). The maximum post-operative difference between predicted and actual refraction ranged from 5.01 to 5.95 for all formulas. The percent of cases which had an error greater than 2 D ranged from 13.6% for the Holladay 2 and Hoffer Q to 18.2% for the SRK-T and Holladay 1. Conclusion: The mean absolute error (predicted vs. actual) was less than 1.4 D for each of the four intraocular lens formulas compared retrospectively in pediatric eyes. No individual formula outperformed the others.
Keywords: 543 refractive error development • 551 refractive surgery: phakic IOL • 623 visual development: infancy and childhood