A randomized, single-center study of equivalence of 2 intraocular lenses used in cataract surgery

Correlation and predictability of ocular aberrations and the visual outcome after quadrifocal intraocular lens implantation: a retrospective longitudinal study

Background

To evaluate the correlating and predicting factors of visual outcome after implantation of newly developed diffractive quadrifocal intraocular lens (IOL).

Methods

A retrospective longitudinal study was conducted. Patients who underwent diffractive quadrifocal IOL implantation with a follow-up period longer than six months and records of wavefront aberrometer within one week perioperatively were enrolled. Accordingly, a total of 73 eyes from 73 patients were included. The postoperative distance and near visual acuity, ocular aberrations and postoperative symptoms were collected. The correlation and predictability between ocular aberrations and the postoperative visual outcome were evaluated.

Results

The corrected distance visual acuity (CDVA) one month postoperatively was significantly better than the preoperative status, and insignificant improvement was found six months postoperatively. Preoperative Tracey refraction spherical equivalent (TRSE), angle alpha, and spherical aberration (SA) were significantly correlated with postoperative CDVA and near corrected visual acuity (NCVA). For postoperative ocular aberrations, TRSE, angle alpha, and SA were significantly correlated with CDVA six months postoperatively and NCVA, while the trefoil, internal higher order aberration (HOA) and total HOA were associated with NCVA. Preoperative angle alpha could predict all postoperative visual performances, while postoperative TRSE and angle alpha could predict the CDVA six months postoperatively and NCVA. A large angle alpha is associated with visual disturbance and dissatisfaction.

Conclusion

The angle alpha preoperatively and postoperatively was correlated with the postoperative vision and could predict visual outcome in patients who had diffractive quadrifocal IOL implanted. Furthermore, the majority of ocular aberrations were also associated with certain postoperative vision.

Development of visual Neuroprostheses: trends and challenges

Visual prostheses are implantable medical devices that are able to provide some degree of vision to individuals who are blind. This research field is a challenging subject in both ophthalmology and basic science that has progressed to a point where there are already several commercially available devices. However, at present, these devices are only able to restore a very limited vision, with relatively low spatial resolution. Furthermore, there are still many other open scientific and technical challenges that need to be solved to achieve the therapeutic benefits envisioned by these new technologies. This paper provides a brief overview of significant developments in this field and introduces some of the technical and biological challenges that still need to be overcome to optimize their therapeutic success, including long-term viability and biocompatibility of stimulating electrodes, the selection of appropriate patients for each artificial vision approach, a better understanding of brain plasticity and the development of rehabilitative strategies specifically tailored for each patient.