Vault And Rotational Stability Of Vertical Versus Horizontal Implantation Of The Implantable Collamer Lens: A Systematic Review And Meta-Analysis

Published 2026 - 44th Congress of the ESCRS

Reference: PP07.01 | Type: Free paper | DOI: 10.82333/k7pc-5z18

Authors: Dr Nuno Rodrigues Alves* ¹ , Catarina Barão ¹ , Matheus Pedrotti Chavez ² , Vítor Maduro ¹ , Nuno Filipe Alves ¹ , Prof. Dr Sorcha Ní Dhubhghaill ³ , Pedro Gil ¹

¹Department of Ophthalmology,Unidade Local de Saúde de São José,Lisbon,Portugal, ²Department of Ophthalmology,Universidade Federal de Santa Catarina,Florianópolis,Brazil, ³Department of Ophthalmology,University Hospital Brussels,Brussels,Belgium

Purpose

To compare postoperative vault, rotational stability, and refractive outcomes between vertical and horizontal Implantable Collamer Lens (ICL) implantation in adults with myopia.

Setting

Department of Ophthalmology, Unidade Local de Saúde de São José, Lisbon, Portugal.

Department of Ophthalmology, University Hospital Brussels, Brussels, Belgium.

Methods

Following PRISMA 2020 guidelines (PROSPERO CRD420251241892), PubMed, Embase, and the Cochrane Library were searched for randomized and non-randomized studies comparing vertical (V-ICL) versus horizontal (H-ICL) ICL implantation. The primary outcome was postoperative vault. Secondary outcomes included absolute rotational angle, spherical equivalent (SE), the proportion of eyes with rotation >5°, adverse events (intraocular pressure [IOP] and endothelial cell density [ECD]), and weighted mean efficacy and safety indices. Data were pooled using random-effects models, and heterogeneity was assessed using the I² statistic. Analyses were performed using R software.

Results

Eleven studies including 4,603 eyes (V-ICL: 2,446; H-ICL: 2,157) from 3,216 patients were analyzed. V-ICL implantation was associated with a significantly lower postoperative vault compared with H-ICL implantation (MD = −75.17 µm; 95% CI: −130.63 to −19.72; p = 0.001; I² = 84%). Secondary outcomes, including mean absolute rotational angle (MD = −0.65°; p = 0.16), SE (MD = 0.05 D; p = 0.307), the proportion of eyes with rotation >5° (RR = 0.81; p = 0.423), and IOP (MD = 0.25 mmHg; p = 0.106), were not significantly different between groups. ECD was slightly lower in the V-ICL group (MD = −49.34 cells/mm²; 95% CI: −68.41 to −30.26; p = 0.012; I² = 0%). Efficacy and safety indices were comparable (V-ICL: 1.04/1.12 vs H-ICL: 1.04/1.10).

Conclusions

Vertical ICL implantation results in lower postoperative vault compared with horizontal implantation without compromising rotational stability or refractive outcomes in myopic patients. Although endothelial cell density was modestly lower with vertical placement, both orientations appear equally safe and effective, allowing surgeons flexibility in lens positioning based on anatomical or surgical considerations. Further well-designed, long-term studies are warranted to determine the clinical significance of these subtle differences.