IOL choice is not a one-size-fits-all situation. Refractive cataract surgeons should personalize both the IOL and the refractive target to best suit the needs, lifestyle and optical circumstances of each cataract surgery client.
The IOL selection decision process depends on a host of factors, including but not limited to:
- manifest refraction;
- aberration profile;
- height and arm length;
- work and hobbies; and
- distance at which spectacles would be least bothersome.
For a patient with healthy eyes and a desire for spectacle independence, here is the three-step process we follow:
Step 1: Determine eye dominance
Motor dominance is an efficient test for the clinic and generally conclusive. For equivocal cases, however, we test for optical dominance by introducing a +1.50 blur to the best corrected vision. The eye that tolerates the blur better is the optically nondominant eye.
Step 2: Choose the IOL and refractive target for the dominant eye
Most commonly, I would implant a Tecnis Symfony extended-depth-of-focus (EDOF) lens (Johnson & Johnson Vision) in the dominant eye first because it offers high quality of vision, with image contrast rivaling that of a monofocal lens, while allowing us at the same time to extend the depth of focus for intermediate and near vision tasks. I like to target plano, choosing the IOL power that gives a predicted residual error closest to zero on the plus side for the dominant eye.
Step 3: Choose the IOL and refractive target for the nondominant eye
For example, in a tall plano presbyope or hyperope with average visual needs I am most likely to take advantage of an EDOF lens in both eyes, targeting the IOL power closest to plano but on the minus side for the nondominant eye. It would also be reasonable to add a small amount of myopic defocus in the nondominant eye. But if the individual was short, a low myope and/or had a specific hobby that required extended close work, I might instead choose a mid-add diffractive bifocal such as the ZLB00 (Tecnis multifocal +3.25, Johnson & Johnson Vision) to broaden the near reading range. In a recent study of 24 patients with this IOL combination, 96% achieved 20/20 or better distance, 91% achieved 20/25 or better intermediate and 93% achieved 20/25 or better near acuity 3 months after surgery.
We typically plan the pair of lenses from the outset — always with the goal of achieving the broadest degree of spectacle independence while maximizing quality of vision. However, depending on how close together the first and fellow eye surgeries are, you may wish to take the patient’s subjective reaction to the first lens into consideration in selecting the second IOL.
Disclosure: Waring reports he is a consultant for Johnson & Johnson Vision and a member of the Johnson & Johnson Vision Optics Advisory Board.