This large retrospective study analyzed the incidence and appropriate timing of repositioning surgery to correct misalignment of toric IOLs.
The retrospective, multicenter case series included 6,431 eyes who received acrylic foldable toric IOLs after phacoemulsification. Outcomes included rate and timing of IOL repositioning, as well as residual IOL misalignment, refractive outcome and need for additional realignment. Final measurement of alignment after repositioning was obtained at a mean of 7.6 weeks postop.
Forty-two eyes (0.653%) underwent repositioning surgery at an average of 9.9 days (range 0–30 days) after IOL implantation.
The interval from cataract surgery to repositioning procedure was negatively correlated with the degree of residual misalignment (P<0.001). When repositioning was performed within 6 days after surgery, the mean residual misalignment of 13.1°. In contrast, when surgeons performed repositioning at 7 days or later, mean residual misalignment was 6.3°.
Of note, 2 eyes that were treated within 24 hours after cataract surgery experienced significant IOL re-rotation. Both patients required additional surgical intervention.
The study was retrospective, but was well-powered. Also, factors other than rotation could have contributed to misalignment, such as marking and placement of IOL at time of surgery. Lastly, the study does not take into account surgeons that chose not to realign the lens, even if misalignment was present.
This rate of repositioning reported in this study is relatively low (<0.7%). Previous studies have reported rates between 1.1% to 2.3%.
Outcomes are best if the surgeon waits 1 week. There is also considerable difficulty in rotating the IOL later, due to capsular bag contraction. As such, the “sweet spot” to reposition an IOL is probably within 1 to 3 weeks after cataract surgery.