IOL calculation using six formulas in children undergoing lens extraction and primary IOL implantation with and without posterior optic capture

To evaluate formulas for intraocular lens (IOL) calculation in children undergoing lens extraction and IOL implantation.

Retrospective, consecutive case series at the Department of Ophthalmology, Goethe University Frankfurt, Germany. We included eyes that received lens extraction and IOL implantation (SN60AT, Alcon, Fort Worth, TX) due to congenital or juvenile cataract. Preoperative assessments included biometry (IOLMaster 500/700, Carl Zeiss Meditec, Germany). To evaluate the measurements, we compared the mean prediction error (MPE), mean and median absolute prediction error (MAE, MedAE) of six different formulas, and number of eyes within ± 0.5, ± 1.0, ± 2.0D of target refraction. Postoperative spherical equivalent was measured by retinoscopy 4–12 weeks after surgery.

66 eyes matched our inclusion criteria with a mean age of 6.3 years ± 3.2. MedAE was lowest in SRK/T (0.55D ± 1.08) followed by Holladay I (0.75D ± 1.00), EVO 2.0 (0.80D ± 0.89), Barrett Universal II (BUII, 0.86D ± 1.00), Hoffer Q (0.97 D ± 0.94), and Haigis (1.10D ± 0.95). Regarding eyes within ± 0.5D SRK/T (45.5.%, 30 eyes) performed best, followed by Holladay I (36.4%, 24 eyes), EVO 2.0 and BUII (each 34.8%, 23 eyes). There was a myopic shift seen in all formulas (MPE: -0.21 to -0.90D).

Using modern formulas, or even AI formulas, for IOL calculation in children’s eyes does barely improve predictability of the postoperative refraction. A myopic shift can be found for all formulas. However, specific formulas like SRK/T seem to better anticipate this.