Monocular Diplopia 22 Years After Anterior Chamber Intraocular lens Implantation: A Case Report

Abstract Background：Angle-supported anterior chamber intraocular lenses provide a technically straightforward solution for aphakic eyes lacking capsular support, yet their long-term complications warrant critical attention. We present a case of monocular diplopia occurring 22 years after ACIOL implantation for congenital cataract, analyzing the mechanisms of corneal endothelial loss and surgical management strategies to elucidate the delayed risks associated with anterior chamber IOLs. Case Presentation：A 29-year-old female presented with painless monocular diplopia in her left eye, 23 years after staged bilateral congenital cataract surgery (lensectomy at 6 months, followed by secondary IOL implantation at age 6: right eye in-the-bag IOL, left eye angle-fixated ACIOL due to inadequate capsular support). Examination revealed ACIOL-induced angle obstruction with pupillary distortion (confirmed by ultrasound biomicroscopy) and an endothelial cell density of 1,552.3 cells/mm² in the left eye (vs. 1,271.0 cells/mm² in the right). The patient underwent ACIOL explantation combined with anterior vitrectomy and pupilloplasty to halt progressive endothelial loss and resolve diplopia. At 3-month follow-up, iris architecture remained stable with preserved endothelial density (1,526.8 cells/mm²), though medically controlled elevated IOP (19-26 mmHg) was noted. Ongoing monitoring is maintained. Conclusion：This case demonstrates a 22-year latency period for ACIOL-related complications, underscoring the need for prompt removal upon visual quality deterioration (e.g., diplopia) or significant endothelial decline. Secondary IOL implantation should be individualized (sulcus vs. scleral-fixated), with lifelong surveillance for IOP, endothelial function, and retinal status. These findings carry critical implications for pediatric IOL selection and lifelong postoperative management.