Currently, reports of ICL dislocation resulting from trauma are relatively rare3. Patients often seek emergency medical attention due to loss of vision following injury. In almost all reported cases, the patients underwent ICL repositioning surgery3,6-8. On presentation, the patient underwent surgical management to reposition the ICL. Comprehensive examinations of anterior chamber and vitreous cavity indicated the integrities of both the zonule fibers and the capsule, suggesting removal of the ICL may not be necessary. The reset direction was thrown horizontally rather than vertically, because of the non-astigmatic design of the ICL and the intact zonules. Replacement with a new ICL was not scheduled since no evidence of ICL damage was observed.
To date, only one case of ICL dislocation into the vitreous cavity due to spontaneous zonules rupture has been reported, which resulting in explant of the dislocated ICL8. It is imperative that prior to conducting such a surgical procedure, careful examination of the zonule fibers around the lens of the affected eye should be conducted, with particular attention given to the zonules at the ICL implantation site. In the instance at hand, the horizontal zonules remained intact and the ICL was non-astigmatic, thus the reset direction was thrown horizontally. Preoperative data of the initial ICL implantation in both eyes is important for designing the repositioning surgery and estimation of the ICL vault after reposition. However, perioperative medical history of the initial surgery may not be available at presentation, thus the current ICL vault of the patient's uninjured eye should be fully taken into account. As for the sulcus to sulcus distance in the vertical direction was always larger than that of the horizontal direction9, careful considerations should be taken for the estimated ICL vault after reposition of the dislocated ICL to a vertical position, when considering potential damaged zonules at the horizontal. In particular, the direction of ICL reposition and implantation should be adjusted with reference to the uninjured eye of the patient so as to prevent any further complications arising from excessive or low vault post-surgery. Carefully consideration of repositioning the axis of astigmatism and the need of ICL replacement are required when the dislocated ICL lens was designed to correct astigmatism10.
In the case of trauma-induced ICL dislocation with pupil capture, we hypothesize that the mechanism of injury involves the compression and deformation of the eyeball by blunt trauma, given the extremely soft nature of the ICL lens. The lens's foot plate moves towards aqueous humor extrusion and then prolapses into the anterior chamber angle. The chamber angle recedes due to torn ciliary body circular muscle and longitudinal muscle caused by blunt force. The literature has reported that the risk of ICL dislocation is greater when the pupil is dilated at night10. In our case, the incident occurred at approximately 5 o'clock in the afternoon, and the dilated pupil is not believed to be a major concern at this time11. The timing of the trauma may be attributed to chance. We hypothesized that the increased excitability of the sympathetic nerve and the dilated pupil in the stress state at the time of injury might be the possible causes of the dislocation of the ICL into the anterior chamber of the eye.
In summary, we present a rare case of ICL dislocation following blunt trauma, which can lead to long-term complications. Prompt identification of dislocation is crucial to prevent complications. Thorough examination is necessary to diagnose dislocation, preventing issues such as endothelial damage and corneal decompensation. Repositioning and implantation of the ICL should be adjusted based on the patient's uninjured eye to avoid further complications. In this case, the patient underwent surgical repositioning of the ICL, resulting in a stable location with no significant changes in vault. Timely intervention and careful management can reduce the risk of complications in challenging cases.