The Etiology of Intraocular Lens Dislocation and Changes in Intraocular Pressure After Intrascleral Intraocular Lens Fixation Surgery

Objectives This study aimed to identify the etiology and the direction of dislocation of the natural crystalline lens or intraocular lens (IOL) in IOL intrascleral fixation surgery and to determine the change in intraocular pressure (IOP) after surgery. Methods We retrospectively investigated the diagnosis, direction of lens and IOL dislocation, and IOP before and after surgery (preoperatively and one day, one week, and one month postoperatively) in 236 eyes from 228 patients who underwent IOL intrascleral fixation at Chiba University Hospital between February 2015 and September 2020. Results IOL intrascleral fixation was performed in 48 (20.3%) patients with long eye axis, 44 (18.6%) with pseudoexfoliation (PEX), 42 (17.8%) with intraoperative problems such as ciliary zonule rupture or posterior capsule rupture, 40 (16.9%) with a history of trauma, 34 (14.4%) with a history of vitrectomy, 21 (8.9%) with atopic dermatitis, six (2.5%) with genetic diseases such as Marfan syndrome, four (1.7%) with retinitis pigmentosa, and 58 (24.6%) with unknown causes. Downward IOL dislocation was the most common (52 cases), while IOL falling into the vitreous cavity was seen in 46 cases, aphakic eye in 31 cases, and anterior lens dislocation in 16 cases. In general, IOP was significantly lower at one month postoperatively than preoperatively. Specifically, in the trauma, PEX, and unknown causes groups, as well as the groups with anterior lens deviation, IOL fell into the vitreous cavity, and with IOL downward deviation, IOP was significantly lower. Conclusion IOP was significantly lower one month postoperatively than preoperatively after IOL intrascleral fixation. Patients who underwent IOL intrascleral fixation surgery were most commonly found to have long eye axis, PEX, and intraoperative problems. Downward deviation of the IOL or IOL falling into the vitreous cavity was most common. IOP was significantly lower one month postoperatively than preoperatively after IOL intrascleral fixation.