Comparison of far and near contrast sensitivity in patients symmetrically implanted with multifocal and monofocal IOLs.

Purpose: A prospective, randomized, double-masked, clinical trial was designed to evaluate distance and near contrast sensitivity (CS) in patients symmetrically, and randomly, implanted with 4 different multifocal intraocular lens (MIOL) designs (ReSTOR SN6AD1, ReSTOR SN60D3, ReZoom NXG, and Tecnis ZMA00) and a monofocal control group (Tecnis ZA9003), 6 months after cataract intervention.

Methods: Photopic, mesopic, and mesopic with glare distance CS, as well as photopic near CS, was evaluated with the CSV-1000 CS test and the Vistech VCTS 6000 system, respectively, in a group of 180 patients attending the ophthalmology department of Sant Pau Hospital, Barcelona, for cataract intervention and lens implantation.

Results: Statistically and clinically significant differences were found between the monofocal and multifocal lens groups at all spatial frequencies and illumination conditions, both during distance and near CS evaluation (all p<0.05), with the monofocal lens offering the best performance in all cases. Contrast sensitivity was similarly compromised in all MIOL models at distance, although MIOLs with diffractive optics and aspheric profiles showed a non-statistically significant trend to perform better in mesopic conditions. Near CS was lower for refractive, distance dominant lens designs, particularly at medium to high spatial frequencies.

Conclusions: The present results, which reflect intraocular lens (IOL) characteristics in optics, profile, and add power, may contribute to help surgeons decide on the type of IOL most suitable for each patient by taking into consideration the individual needs for critical distance and near vision, both in terms of visual acuity and contrast sensitivity.