Mixing and matching multifocal IOLs appears to be a safe and effective approach, according to a study of two lenses from the same manufacturer (Tecnis and ReZoom, Advanced Medical Optics). The surgeon who conducted the research provides pearls for using this technique.
Dr. Piovella, director, Centro Microchirurgia Ambulatoriale, Monza, Italy, has performed 43 cataract (mean age 75.0 years) or clear lens extraction (mean age 50.5 years) cases followed by implantation of the mixed IOLs. Postoperatively, the bilateral uncorrected visual acuity for distance vision was 0.9 D. Uncorrected intermediate and near vision were, respectively, J2 and J3; about 85% of patients were able to read at J2. Mean reading speed 1 month postoperatively was 65.4 words per minute. In contrast, when the eyes were measured separately, the visual acuity results were unsatisfactory, he said.
Other outcomes from the study showed that 47% of patients experienced slight glare during night driving, and only one had significant difficulty with this task. No lenses were explanted.
It is important to note that the refractive lens is more pupil-dependent, whereas the diffractive is less so; conduct careful patient exams before implantation, Dr. Piovella said. He and colleague Barbara Kusa, MD, have learned that results with the refractive IOL will be better if the pupil diameter is no larger than 5.2 mm; in larger pupils, the patient is likely to experience halos postoperatively under scotopic conditions. It is safe, however, to implant the diffractive lens.
In his clinic, the diffractive IOL usually is implanted first in the nondominant eye. If the patient has no complaints postoperatively, then the refractive lens will be placed in the dominant eye.
If the patient experienced halos, however, then the same IOL would be implanted in the other eye. If the patient's eyes are similar, Dr. Piovella said, it is best to implant similar lenses. Also, he said, the same lenses should be used in both eyes if it is difficult to determine which is dominant.
Patients also should be informed prior to surgery that they might need to use monocular glasses under some circumstances, Dr. Piovella said.
He offered a series of pearls for mixing multifocal IOLs: