A new strategy to calculate the intraocular lens power in congenital cataracts according to age and axial length at implantation.

PURPOSE: The purpose of the study was to suggest a new method to calculate the intraocular lens (IOL) power in paediatric cataracts targeting emmetropia at the age of 15 years.

METHODS: Data of children younger than 15 years who underwent cataract surgery with IOL implantation between 2005 and 2020 in the ophthalmological department of Marseille (South of France) was collected retrospectively. A logarithmic regression model was used to predict the axial length growth of the included eyes between implantation and 15 years. The predicted myopic shift served as target refraction to calculate a theoretical IOL power aiming for emmetropia at 15 years. Refractive error with the theoretical lens power was estimated as the spherical equivalent at the last follow-up minus the difference of target refractions between the implanted IOL and the theoretical one. Refractive errors using Dahan, Enyedi and Trivedi guidelines were also estimated and compared to the logarithmic model.

RESULTS: Thirty-five eyes of 26 children were analysed. At the last follow-up, the median age of children was 10 years old and the median spherical equivalent was -1.88 dioptres (D) (IQR -3.81, -0.75). The estimated median refractive errors were 0.18 D (IQR -1.11, 1.42) with the logarithmic formula, -1.47 D (IQR -3.84, -0.65) with Dahan formula, -0.63 D (IQR -2.15, 0.32) with Enyedi formula and 0.38 D (IQR -1.58, 1.07) with Trivedi formula.

CONCLUSION: The estimated refractive error with the new logarithmic formula is the closest to emmetropia at the last follow-up.