Bilateral IC-8 implantation viable strategy for presbyopic patients
Bilateral implantation of small-aperture IOLs can be a successful strategy for presbyopia correction, according to a study.
To compare visual acuity after contralateral vs. bilateral implantation of the IC-8 IOL (AcuFocus) in cataract patients, Robert E. Ang, MD, of Asian Eye Institute, Philippines, implanted 10 patients bilaterally with the IC-8 and 10 patients monolaterally with the IC-8 in one eye and a monofocal IOL in the other.
At 12 months postoperatively, all 20 patients achieved 20/32 or better binocular uncorrected distance visual acuity and corrected distance visual acuity at all distances. In bilaterally implanted patients, near vision range increased 0.25 D, and intermediate and near distance visual acuities improved by 0.5 lines.
“Previous experience and reports have demonstrated the effectiveness of the IC-8 small-aperture IOL in providing extended depth of focus after monolateral implantation during cataract surgery. The results of our study provide data that bilateral implantation is feasible and effective,” Ang told Healio/OSN. “There was an improvement in intermediate and near vision with bilateral implantation without additional detriment in contrast sensitivity.”
Without reaching statistical significance, bilaterally implanted patients reported more glare and halos than contralaterally implanted patients.
Overall satisfaction was better in the bilaterally implanted patients, although patient selection was cited as a likely factor influencing that result. Patients who received the IC-8 in their second eye were self-selected after having a positive experience with the IOL in their first eye. Patients in both groups said they would undergo the procedure again.
“The implications of these findings are significant because in real-world usage, presbyopia-correcting IOLs are implanted bilaterally and have synergistic effects in providing better distance, intermediate and near vision. Second, small-aperture IOLs have the potential of helping patients with aberrated corneas, and in many cases these problematic corneas are present in both eyes,” Ang said. – by Robert Linnehan
Disclosure: Ang reports he has received grants from AcuFocus and PhysIOL.
Perspective
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After a mostly positive experience with the Kamra corneal inlay for presbyopia, many surgeons in the United States are anxiously awaiting the reincarnation of the small-aperture design incorporated into an IOL. The IC-8 IOL (AcuFocus) is a one-piece hydrophobic acrylic posterior chamber monofocal IOL that provides increased range of vision from far to near by extending the depth of focus using the pinhole principle. The original indication for both the corneal inlay and the IC-8 was for unilateral implantation in the nondominant eye. However, several studies have now shown that bilateral implantation of the IC-8 may confer certain advantages, especially if the second eye operation considers results from the first surgery and allows for adjustment of the target refractive error.
In this series, bilaterally implanted patients had better overall satisfaction, improved satisfaction with near tasks and increased spectacle independence, and they rated many near tasks to be easier to perform as compared with their unilateral counterparts. Bilateral patients also felt that distance activities such as driving were slightly better than unilaterally implanted patients. On the flip side, they also reported slightly more glare and halos, although this did not reach statistical significance. The author does point out that the higher-level satisfaction expressed by patients with bilateral IC-8 IOLs vs. unilateral implantation may likely be due to the patient selection process. Only those patients who had a positive response to their first eye and who specifically asked for second-eye implantation with IC-8 were included in the analysis. If patients had diminished distance acuity following the first eye, the second eye was targeted for emmetropia; in contrast, if the first eye left the patient complaining of near vision ability, the target was adjusted for slight myopia. Binocularity also delivered increased range of vision at intermediate and near for these patients, as evidenced by shifting of the binocular defocus curve by 0.25 D toward the negative direction, which effectively expanded the near vision range by 0.25 D and may also have contributed to the higher satisfaction scores.
This study highlights a positive response to bilateral implantation of the IC-8 IOL in the treatment of cataract and presbyopia. The design and mechanism of action of this lens, as compared with a multifocal lens, may allow it to be effectively implanted over a wide range of refractive error, including astigmatism, and may be a viable alternative in patients with prior keratorefractive surgery, keratoconus and mild macular pathology.
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