Purpose/Aim: To evaluate the impact of ocular parameters on the visual performance achieved with the multifocal intraocular lens (IOL) Bi-Flex M 677MY.
Materials and Methods: 26 subjects were included in the current study. Several physiological variables were retrieved from the 3-month follow-up visit, including pupil diameter and distance from pupil center to the vertex normal of the anterior cornea (µ). These variables were also obtained in the preoperative visit. Binocular and monocular visual acuity defocus curves were measured at 1 and 3 months after surgery, respectively. The area under the monocular defocus curve was computed along the total curve (TAUC, +1.00 to −4.00 D) and for the ranges of far (FAUC, +0.50 to −0.50 D), intermediate (IAUC, - 1.00 to −1.50 D) and near vision (NAUC, −2.00 to −4.00 D). Correlations between these areas and the postoperative physiological variables were assessed.
Results: The mean µ was reduced from 0.21 mm to 0.10 mm after surgery, as well as pupil diameters, either photopic (−7.4%) and mesopic (−8.1%) (p < 0.05). The mean AUCs were 2.08 ± 0.74 for TAUC, 0.57 ± 0.17 for FAUC, 0.16 ± 0.09 for IAUC and 0.81 ± 0.29 for NAUC. Significant correlations were found between NAUC and Km (r = −0.39, p = 0.05) as well as between IAUC and temporal decentration of the lens from vertex normal (ρ = −0.41, p = 0.04).
Conclusions: The performance at near with the IOL evaluated improved in eyes with less corneal power. On the other hand, a slight temporal IOL decentration from vertex normal also improved intermediate visual acuity. The binocular defocus curve was similar to other trifocal IOLs.