Accuracy of using the axial length of the fellow eye for IOL calculation in retinal detachment eyes undergoing silicone oil removal

Evaluate whether the axial length of the fellow eye can be used to calculate the intraocular lens (IOL) in eyes with retinal detachment.Retrospective, consecutive case series.Our study was conducted at the Goethe University and included patients who underwent silicone oil (SO) removal combined with phacoemulsification and IOL implantation. Preoperative examinations included biometry (IOLMaster 700, Carl Zeiss). We measured axial length (AL) of operated eye (OE) or fellow eye (FE) and compared mean prediction error and mean and median absolute prediction error (MedAE) using four formulas and AL of the OE (Barrett Universal II (BUII)-OE). Additionally, we compared the number of eyes within ±0.50, ±1.00 and ±2.00 dioptre (D) from target refraction.In total, 77 eyes of 77 patients met our inclusion criteria. MedAE was lowest for the BUII-OE (0.42 D) compared with Kane-FE (1.08 D), BUII-FE (1.02 D) and Radial Basis Function 3.0 (RBF3.0)-FE (1.03 D). This was highly significant (p<0.001). The same accounts for the number of eyes within ±0.50 D of the target refraction with the BUII-OE (44 eyes, 57%) outperforming the RBF3.0-FE (20 eyes, 25.9%), Kane-FE and BUII-FE formula (21 eyes, 27.2%) each.Our results show a statistically and clinically highly relevant reduction of IOL power predictability when using the AL of the FE for IOL calculation. Using the AL of the SO filled eye after initial vitrectomy results in significantly better postoperative refractive results. A two-step procedure using the AL of the OE after reattachment of the retina is highly recommended.