The effect of misalignment on the refractive outcome worsens with increasing cylinder power of the toric lens. For example, 5° of misalignment results in 17.5% loss of effect, but that translates into a loss of 0.18 D for a toric IOL with 1.03 D of cylinder power at the corneal plane and 0.71 D for an implant with 4.11 D of cylinder power at the corneal plane.
Surgeons should wait at least 1 week after the primary surgery before rotating the toric IOL and can wait up to 1 year, Dr. Berdahl said. While ideally it may be better to do the procedure sooner than later to reduce the patient wait time to have good uncorrected vision, patience may pay off because it may decrease the likelihood that the lens will re-rotate.
To perform the rotation, surgeons should mark the current and ideal axis, instill viscoelastic to inflate and protect the capsular bag, and place viscoelastic under the IOL to free the implant from the cul de sac. Using a Sinskey hook, they should then make sure the haptic is freed from the posterior capsule and use the instrument to rotate the IOL into the desired position. Viscoelastic is then removed.