o r I g I n A L A r t I C L e ultifocal intraocular lenses (IOLs) were introduced in cataract surgery to address the problem of loss of accommodation following lensectomy and implantation of a monofocal IOL. There have been different multifocal designs, including diffractive bifocal, 1 apodized diffractive, 2 trifocal, refractive, zonal refractive, 1 rotational asymmetric refractive, 3 and accommodating IOLs in which the optic or optics need to move to achieve accommodation. 4 Bifocal diffractive apodized IOLs have a circular pattern on the optic surface, which allows for diffraction of incoming light into two main distinct foci. One focus is for distance vision and the secondary focus is for near vision. The diffraction patterns distribute the light to both foci with loss of energy; approximately 18% of light is directed outside the far and near focal points.2 As a result of multiple foci occurring in the eyeball at the same time and interfering with one another, the contrast sensitivity for both far and near foci decreases.
5In apodized diffractive IOLs, the far focus is dominant and receives more light, whereas the near focus receives less light.
2The patterns of the apodization can differ and not only allow changes in depth of focus with relation to the intensity of light distributed between the far and the near foci, but also changes in induced halos, contrast, and quality of vision with relation to the pupil size as a function of light intensity as part of the accommodative triad response. 6,7 M ABSTRACT PURPOSE: To evaluate differences in straylight between eyes implanted with a hydrophilic multifocal IOL (Seelens MF; Hanita Lenses, Hanita, Israel) and a hydrophobic multifocal IOL (SN6AD1; Alcon Laboratories, Inc., Fort Worth, TX).
METHODS:In a prospective cohort study, routinely obtained straylight measurements (C-Quant; Oculus Optikgeräte, Wetzlar, Germany) 3 months after standard phacoemulsification for either cataract or refractive lens procedures were compared. Patients were implanted with either the SeeLens MF IOL or the SN6AD1 IOL. Postoperative straylight values, visual acuity, and refractive outcomes were compared.
RESULTS:The SeeLens MF IOL was implanted in 84 eyes and the SN6AD1 IOL in 79 eyes. The difference in straylight was 0.08 (P = .01), with the SeeLens MF IOL having less straylight. Postoperative CDVA was logMAR -0.03 ± 0.06 in the SeeLens MF group, and logMAR -0.02 ± 0.08 in the SN6AD1 group. Mean postoperative refraction was +0.01 ± 0.43 and +0.06 ± 0.35 D, respectively.
CONCLUSIONS:The Seelens MF IOL showed a straylight of log(s) 0.08 lower than the SN6AD1 IOL. In terms of spherical equivalent and visual acuity the lenses performed equally. More study will aid in understanding the causes and clinical impact of this difference.[J Refract Surg. 2015;31(11):746-751.]