A resurgence could create new possibilities in refractive correction
The restoration of accommodation in pseudophakia is indeed the last holy grail to be accomplished in cataract surgery. Most probably, we can state that once accommodation can be e˜ectively restored with an IOL, the era of modern cataract surgery in terms of the development of surgical techniques and IOLs will be fnished and its accomplishment will be the fnal landmark in this process.
However, the restoration of human eye accommodation is not easy. Many lenses have been proposed in the past with great disappointment. Some models, with single or dual optics, following initial positive results, failed to be demonstrated as truly accommodative in independent studies.
Another problem with accommodative lenses is where the lens should be placed. Studies that have been performed in primate models have demonstrated that the capsular bag is not an adequate place to allocate an accommodative lens as fbrosis and lack of accommodative performance have been demonstrated consistently.
The sulcus has been defned as the best place for an accommodative lens based on studies performed on a primate animal model, an issue that was later confrmed in pilot clinical trials.2,3 The sulcus indeed seems to be the best place for an accommodative lens.
Recently, a new sulcus-based accommodative intraocular lens, the Lumina (AkkoLens), based on the Alvarez principle, has been described, and published with evidence.4 This innovative IOL consists of two varifocal optical surfaces that, when one slides onto the other on the frontal plane, cause a continuous change in the optical power of the eye according to the distance of fxation. Evidence has been published which has demonstrated in pilot phase 2/3 clinical trials that accommodation is gained in functional levels with excellent clinical safety.5
Recently, a new phase 3 study has been reported and will soon be published in the scientifc literature concerning this new concept.
The phase 3 study demonstrates that the Lumina lens accomplishes good far and near visual performance, with a gain in accommodation of up to 2.5 D measured
with new methods to objectively measure the power of the eye according to distance and near fxation: the open feld aberrometry and the new Plusoptix technology.
The patient-reported outcomes of the study demonstrated that this lens, on the contrary to multifocal and some extended depth of focus (EDOF) lenses, does not cause photic phenomena, and the neuroadaptation process needed postoperatively is minimal.8,9 This is a most relevant subject as photic abnormal phenomena are the main drawback of multifocal and EDOF lenses and can lead to explantation due to neuroadaptation failure.
In other words, accommodation seems to be now an accomplished goal in cataract surgery. IOLs with capability to accommodate will be, once they are generalised, the fnal step to accomplish cataract and IOL implantation in the modern era. This impressive step forward needs to be the subject of further multicentric trials, but it seems that today, the door is open for a new type of IOL surgery.