Laboratory Evaluation of Optical Performance of Aspheric Monofocal Intraocular Lenses With Various Anti-misalignment Designs Under the Influence of Decentration and Tilt.

PURPOSE

To assess the effectiveness and characteristics of aspheric monofocal intraocular lenses (IOLs) with different anti-misalignment designs.

METHODS

Three types of anti-misalignment IOLs (with aspheric balance curve design, ZO optic design, and high-order optical aspheric surface design) and no anti-misalignment IOLs were involved. From each type of these IOLs, +8.00, +17.00, and +26.00 diopter (D) lenses were used for detection at the 3- and 4.5-mm apertures. The modulation transfer function (MTF) and 50% of the maximum value of the MTF (MTF50) were measured while IOLs were centered, decentered by 0.3, 0.5, and 0.7 mm, and tilted by 3, 5, and 7 degrees.

RESULTS

Within the average clinical range of IOL malpositions (0.3-mm decentration or 3.00-D tilt), the anti-misalignment design slightly reduced the negative effect of decentration and tilt ( = .1845 and .6495, test) on the optical performance of IOLs. Beyond the average range, the anti-misalignment design narrowed the reductions of MTF50 from 23.18% to 8.60% for decentration and from 40.31% to 27.96% for tilt ( = .0010, two-factor analysis of variance). The optical performance varied in anti-misalignment IOLs with different diopters, types, and degrees of malpositions at different aperture sizes. In both photopic and mesopic conditions and all probable misalignments, from the perspective of MTF50, better sharpness generally may be achieved with the 8.00-D ZO optic designed lens and 17.00-D high-order optical aspheric surface designed lens. For 26.00-D IOLs with different misalignments, the ABC design was more resistant to decentrations, whereas the high-order optical aspheric surface design was more resistant to tilts.

CONCLUSIONS

Aspheric monofocal IOLs with an anti-misalignment design can effectively resist decentration and tilt. Anti-misalignment IOLs for complicated cataract could be selected according to diopter of IOL and types and degrees of probable IOL malpositions. .