Congenital cataract surgery: long-term refractive outcomes of a new intraocular lens power correction formula

The final refraction after intraocular lens (IOL) implantation remains a challenge in the management of paediatric cataracts. No consensual guidelines exist for the choice of IOL power. The aim of this study was to validate a method of IOL power calculation by evaluating the final refractive error in all patients with IOL implantation operated at our institution.

We retrospectively studied all children under 7 years of age who underwent cataract surgery with IOL implantation at our institution between 2010 and 2015. Intraocular lens (IOL) power was calculated as follows: After B-scan determination of the emmetropic IOL power, a reduction of 40%, 35%, 30%, 25%, 20%, 15%, 10% and 5% was applied to children 0-3, 3-6, 6-12, 12-18, 18-24, 24-30, 30-36, 36-48 months, respectively. The following data were collected: follow-up, age at surgery, uni- or bilaterality, implanted IOL power and final refraction.

During this period, 81 children (125 eyes) met the inclusion criteria with a median follow-up of 60 months (36-97). The median age at surgery was 6.61 months (0.76-48). We included 52 children with bilateral cataract (96 eyes) and 29 children with unilateral cataract (29 eyes). The mean implanted IOL power was 23.3 ± 4.6 diopters (D). The mean spherical equivalent at last follow-up was 0.07 ± 3.5 D.

Our undercorrection formula for IOL implantation after congenital cataract surgery leads to long-term refractive results globally close to emmetropia.