Palomino Bautista et al Dovepress Figure 1 Lenses with and without chromatic aberration. Notes: This wavelength-dependent refractive error depends on optic material. Materials with a higher Abbe number have lower chromatic dispersion. The posterior surface has a full diffractive optic. This facilitates a constantly balanced light distribution between the distance and near foci and visual performance independent of variations in pupil size. The lens blocks ultraviolet radiation but allows the passage of blue light, which is fundamental to good scotopic sensitivity.7 Blue light is also important for regulating circadian rhythm.8 In 2002, a new type of photoreceptor pigment, called melanopsin, was detected in the cell bodies and dendrites of retinal ganglion cells.9 This pigment is involved in the regulation of circadian rhythm10 and has its absorption maximum in blue light. The hydrophobic acrylic material used in the manufacture of ZMB00 does not show any glistening or calcifications that would affect visual acuity, produce stray light, or diminish contrast sensitivity.12–15 Patients and methods A prospective study was performed in 70 eyes (70 patients) implanted with the Tecnis ZMB00 multifocal lens. The development of postoperative distance and near visual acuity with and without correction was studied at 15, 30, and 60 days. Postoperative contrast sensitivity was studied with the Pelli–Robson test (Haag-Streit, Koeniz, Switzerland) at 60 days. Possible adverse effects (dysphotopsia, halos, glare) were assessed with patient satisfaction questionnaires at every postoperative visit. The distance and near visual acuity results achieved were determined by means of subjective evaluation by the patient and surgeon at each visit. The inclusion criterion for this study was patients with N01–N04 cataracts according to the Lens Opacities Clas- sification System III. The exclusion criterion used in this study protocol was any patient who experienced impairment of visual acuity in some way due to previous systemic or ocular pathology. In accordance with the Declaration of Helsinki, all patients received an explanation of what was going to be done and signed the necessary informed consent form. 404 submit your manuscript | www.dovepress.com Dovepress All patients underwent ultrasound phacoemulsification performed by the same surgeon at the Quirón University Hospital of Madrid. Using topical anesthesia, a clear corneal incision was made with a 2.75 mm calibrated diamond knife along the steep meridian. Biometry, using the IOLMaster® (Carl Zeiss, CZM- Jena, Germany), was performed. The refractive power of the emmetropic intraocular lens was calculated using the SRK-T, Hoffer Q, or Haigis formulae in relation to axial length. Measurements Visual acuity was measured using the logarithm of the mini- mum angle of resolution (logMAR) at 4 m and the standard ETDRS chart (Precision Vision, La Salle, IL) back-lit at 85 cd/m², with the level of luminance as recommended by the Food and Drug Administration and the National Eye Institute for eye examinations. The near visual acuity was measured using a Rosenbaum chart. Patient satisfaction and the incidence of photic phenom- ena at each postoperative follow-up visit was recorded and evaluated. Specifically, patients were asked the following questions: (1) How would you rate your near vision? (2) How would you rate your distance vision? (3) How would you rate your overall vision? (Answers for questions 1–3 were: A, very good; B, good; C, sufficient; D, insufficient.) (4) Do you have visual symptoms such as glare or halos? (Answers were: A, none; B, mild; C, moderate; D, severe). At 60 days, contrast sensitivity at 3 m with the best dis- tance correction was evaluated using the Pelli–Robson test in photopic conditions (85 cd/m²). The test chart consists of eight lines of six letters each, but each line contains two three-letter sets at different contrast sensitivity levels. Read- ing from left to right and top to bottom, log contrast sensitivity increases in 0.15 log steps from 0.05 to 2.30. All letters in the test are the same size, subtending 5° of visual angle at a distance of 3 m, with a line width of 1°. Clinical Ophthalmology 2012:6