Iridocorneal endothelial syndrome manifesting 4.5 years after toric implantable collamer lens implantation: a case report.

backgroundIridocorneal endothelial syndrome (ICE) is a rare unilateral disorder with subtle early manifestations and is therefore easily overlooked in clinical practice. Reports of ICE occurring after implantable collamer lens (ICL) implantation remain exceedingly rare. In the present case, localized peripheral anterior synechiae (PAS) were identified preoperatively, whereas corneal endothelial morphology and endothelial cell density (ECD) were essentially normal. The eye remained clinically stable throughout long-term follow-up until classic features of ICE became apparent 4.5 years later, underscoring the novelty and clinical significance of this case. CASE PRESENTATION: A 19-year-old woman with high myopia underwent bilateral toric implantable collamer lens (TICL) implantation in 2021. Preoperative examination revealed localized PAS and mild superior pupillary displacement in the right eye, while the cornea was clear and ECD was within the normal range. Early and intermediate postoperative follow-up was largely unremarkable. At 4.5 years after surgery, the patient presented with blurred vision in the right eye. Ophthalmic examination demonstrated corneal edema, segmental iris atrophy, progression of PAS, corectopia, and secondary ocular hypertension. In vivo confocal microscopy using the Heidelberg Retina Tomograph III with the Rostock Cornea Module (HRT-RCM) showed disorganized endothelial cell architecture, cellular enlargement, and a marked focal reduction in endothelial cell density. Based on these clinical findings, ICE syndrome of the right eye was diagnosed. The patient subsequently underwent viscocanalostomy, trabeculectomy, and peripheral iridectomy, after which intraocular pressure remained well controlled.Given the patient's history of extreme myopia, ICL explantation was deferred to avoid marked anisometropia and substantial impairment of visual function, and careful follow-up was continued.

conclusionIn patients with preoperative localized PAS or subtle iris abnormalities, underlying ICE cannot be definitively excluded, even when the cornea is clear and ECD is normal. This case suggests that ICE syndrome may exist in a subclinical stage before ICL implantation, with its characteristic features emerging only later in the disease course. Long-term follow-up after ICL implantation is therefore essential, with particular attention to serial assessment of the corneal endothelium, anterior chamber angle, and iris configuration, to enable early recognition of occult progressive disease.