Predictive Value of Intraocular Lens Power Calculation Formulae in Children

Abstract

Purpose To compare the accuracy of IOL power calculation formulae in a large cohort of children who underwent IOL implantation. Setting Cairo University Children Hospital. Design Retrospective, case series. Methods A retrospective chart review of all children <14 years, who underwent primary or secondary IOL implantation in Cairo University Children Hospital from January 2016 to December 2019, was performed. Absolute prediction error (APE) was calculated for SRKII, SRK/T, Holladay I and Hoffer-Q formulae using the patients’ AL, keratometric (K) readings, implanted IOL power and refraction done two months postoperatively. Results The study included 308 eyes of 255 patients with a mean age of 4.74 ± 3.19 years at the time of surgery. The mean K-reading was 43.42 ± 3.57 diopters (D) and mean AL was 22.01 ± 1.93 mm. The percentage of eyes with APE within 0.5D was 27.7% (85 eyes), 32.2% (99 eyes), 30.6% (94 eyes) and 25.4% (78 eyes) with SRK II, SRK/T, Holladay I and Hoffer-Q formulae, respectively. APE was significantly lower with the SRK/T formula ( P ≤0.004) and significantly higher with the Hoffer-Q formula ( P ≤ 0.002). There was a negative correlation between the age of the patient and the APE of the SRK II formula ( P =0.02). Moreover, the SRK/T, Holladay and Hoffer-Q formulae APEs were affected by the average k-readings ( P =0.019, 0.005 and 0.035) respectively. Conclusion The SRK/T and Holladay I formulae were the most predictable formulae in IOL power calculation in pediatric eyes.

Intraocular lens calculation using the ESCRS online calculator in pediatric eyes undergoing lens extraction

“…Others report lower predictability using the SRK/T formula as well, with a higher myopic shift, especially in young children, or short and normal eyes and lower amount of eyes within ±0.5 D from target refraction. [16][17][18][19][20][21][22] Others report a hyperopic shift for all of their tested formulas using second and third generation formulas, which is contrary to our results. 22 In previous studies, it was shown that in pediatric cataract surgery, the implantation of an IOL with posterior optic capture is the best alternative to prevent posterior capsule opacification.…”

“…Others report lower predictability using the SRK/T formula as well, with a higher myopic shift, especially in young children, or short and normal eyes and lower amount of eyes within ±0.5 D from target refraction. 16–22 Others report a hyperopic shift for all of their tested formulas using second and third generation formulas, which is contrary to our results. 22…”

Intraocular lens power calculation formula in congenital cataracts: Are we using the correct formula for pediatric eyes?

“…In a recent study, a significant negative correlation between the age of the patient and predictive error of the SRK/T formula was found. [ 37 ] Overall, all IOL power calculation formulae tend to be variable in children, especially in children <2 years, with AL <19 mm and K readings >46.5 D.[ 36 ] In addition, age at the time of surgery significantly contributes to the refractive surprise using all formulas. [ 38 ] SRK/T and Holladay I formulas give better results in children aged less than 2 years.…”