Piggyback Add-on IOL as a Rescue Strategy after Incomplete Deployment of Primary IOL in an Excessively Small Capsular Bag and with Final Unexpected Refractive Benefit

Corrected by: Erratum: Piggyback Add-on IOL as a Rescue Strategy after Incomplete Deployment of Primary IOL in an Excessively Small Capsular Bag and with Final Unexpected Refractive Benefit Klin Monbl Augenheilkd eFirst DOI: 10.1055/a-2826-2346 Background Cataract surgery in small eyes presents distinct challenges due to anatomical variations such as shallow anterior chambers and difficulty with lens calculation [ 1 ]. Several studies have found a generally positive linear correlation between capsular bag or lens diameter and axial length (AL); therefore, it is likely that small eyes are associated with smaller capsular bags [ 2 ], [ 3 ]. It is widely acknowledged that capsular bag size plays a crucial role in determining postoperative IOL position and the likelihood of complications [ 3 ]. Therefore, precise IOL selection and meticulous surgical planning are essential. Moreover, small eyes are associated with a higher risk of intraoperative and postoperative complications such as endothelial trauma, iris prolapse, posterior capsule rupture, zonular rupture, malignant glaucoma and choroidal effusion as well as poorer refractive outcomes, when compared to eyes with normal axial length [ 1 ]. When refractive surprise happens, possible corrective strategies include IOL repositioning, IOL exchange, postoperative corneal refractive surgery, or piggyback IOL implantation [ 1 ]. The aim of this article is to report a previously undescribed complication involving a rectangular IOL implanted in a small eye, highlighting the anatomical challenges associated with short axial length. This case underscores the importance of considering ocular anatomy when selecting and implanting IOLs, particularly in eyes with limited capsular space. Furthermore, it describes the use of a secondary piggyback add-on IOL as a rescue strategy following incomplete deployment of a primary IOL in a presumed undersized capsular bag, which resulted in an unexpected and clinically significant apparent accommodation. The article also explores potential optical mechanisms underlying this phenomenon. Publication History Received: 30 October 2025 Accepted: 15 December 2025 Article published online: 04 February 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/) Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany