The Vaulting Paradox: Navigating Unexpected Posterior Chamber Phakic Iol Hyper Vault In A Perfect Candidate
Published 2026 - 44th Congress of the ESCRS
Reference: POREF013 | Type: Case Report | DOI: 10.82333/mzcy-yh83
Authors: Dr Fernando Augusto Godin Estrada* 1 , Dr Maria Andrea Estevez Florez 1 , Dr Juan Camilo Cadavid Usuga 2 , Dr Guillermo R Vera Duarte 3
1Department of Ophthalmology,Universidad El Bosque,Bogota D.C,Colombia, 2Cornea, Anterior Segment, Refractive Surgery,Clinica Oftalmologica San Diego,Medellin,Colombia, 3Research Department,Oftalmosalud Institute of eyes ,Lima,Peru
Purpose
The purpose of this report is to analyze a case of unexpected and extreme hypervault following the implantation of a posterior chamber phakic intraocular lens (pIOL) in an eye with seemingly perfect preoperative metrics. This case serves to evaluate why traditional manufacturer calculators and white to white measurements may fail to account for complex optical variables such as the Effective Lens Position (ELP) and the shift of principal planes H and H’. By examining this outlier, we aim to highlight the necessity of advanced formulas like the LHC formula, which incorporates a thick lens corneal model and posterior corneal radio to improve predictability.
Setting
The clinical cases and surgical procedures described in this report were managed at the Clínica Oftalmológica
Colsubsidio in Bogotá, D.C., Colombia.
Report of case
A 41-year-old female with a history of bilateral intrastromal corneal ring segments (ICRS) implanted six years ago presented seeking correction for significant residual astigmatism. Examination showed transparent lenses and ICRS at adequate depth. Refraction (Jan 2025): OD -0.50 -4.50x40 (BCVA 20/40) and OS -0.75 -4.50x160 (BCVA 20/40). Pentacam revealed an ACD of 3.04 mm (OU) and pachymetry of 453 µm (OD) and 454 µm (OS).
Using the Care Group IPCL calculator, the suggested lens was an a Toric Implantable Phakic Contact Lens (IPCLT132 V2.0; -3.00D +5.00D CYL at 125°) was implanted in the OD. Postoperatively, the patient reported blurred vision. Examination showed BCVA 20/100, IOP 18 mmHg, and a shallow anterior chamber. AS-OCT confirmed a hypervault of 1357 µm with secondary angle closure. Despite initial conservative management to rule out retained viscoelastic, the refractive surprise and anatomical risk necessitated intervention.
The patient declined further phakic lenses; thus, IPCL explantation followed by bilateral phacorefractive surgery was performed. Despite intraoperative challenges during explantation, endothelial integrity was preserved. A RayOne EMV Toric lens was implanted, targeting monovision (-1.25D in OD; emmetropia in OS). At final follow-up, IOP was 14 mmHg with open angles and stable IOLs. Final BCVA was 20/40 with J1 near vision.
Conclusion/Take home message
This case demonstrates the limitations of standard pIOL sizing protocols and manufacturer nomograms which often overlook the complex optical behavior of meniscus shaped lenses. The unexpected hypervault of 1357 µm despite ideal preoperative biometry proves that predicting the Effective Lens Position (ELP) requires more than static measurements. It necessitates accounting for the migration of principal planes H and H’ as lens power approaches zero. Successful management through phacorefractive surgery with Monofocal Plus toric IOLs confirms that refractive lens exchange is a highly effective rescue strategy. For post ICRS patients, prioritizing formulas like LHC provides long term intraocular pressure stability and visual rehabilitation.