Patient-Perceived and Laboratory-Measured Halos Associated with Diffractive Bifocal and Trifocal Intraocular Lenses.

PURPOSE: To examine and assess the halos generated in distance vision by multifocal intraocular lenses (IOLs) using both in vitro objective and in vivo subjective methods.

SETTING

The objective method was carried out in the optics laboratory of the Applied Optics and Image Processing Group (Universitat Politècnica de Catalunya -Barcelona). The psychophysical and subjective methods were carried out in the Instituto de Oftalmología Avanzada Madrid Innova Ocular.

DESIGN

Optical bench results and prospective evaluation of consecutive cases.

METHODS

The IOLs examined were TECNIS®one-piece bifocals with addition powers of +4.00 D, +3.25 D, and +2.75 D and the trifocals AT-LISA-tri® and FineVision®. In the objective assessment, we examined halos around the far focus images of a pinhole formed by each IOL in an optical bench. For the in vivo study, we recruited 100 patients who had been bilaterally implanted one month earlier with the IOLs under study. Participants were subjected to psychophysical halometry (Halo v1.0) on the eye with better, distance-corrected, visual acuity and were required to subjectively grade halos by responding to the question "How much do halos bother you?"

RESULTS

The objective method revealed that the halo size increased with addition power and that the two trifocals gave rise to a double-halo pattern. Scores in the halometry also indicated a direct relationship between the halo size and addition power. The subjective results indicated fewer complaints about halos associated with the trifocal than bifocal IOLs.

CONCLUSIONS

The addition power of the tested IOLs affected both laboratory-measured and patient-perceived halos. Trifocal lenses generated fewer complaints about halos. Precise: Multifocal intraocular lenses (MIOLs) give rise to halos observed by patients under conditions of dim lighting. This study compares laboratory characterized halos generated by five MIOLs with patient-perceived halos.