No abstract

The trifocal IOL provides a better optical quality at the -1.5 D focal point. However, the optical quality of the trifocal IOL significantly decreases compared to the bifocal IOLs at far distance and -2.5 D focal points.

Purpose:The aim was to assess visual performance after PureVision high addition multifocal contact lens (PM) fitting through contrast sensitivity measured under different illumination levels for both distance and near. Methods: In a cross-over study, 20 presbyopic patients were randomly assigned to PM or spectacles. Near contrast sensitivity was measured with the Vistech VCTS 6500 system. Distance contrast sensitivity and distance visual acuity ( Average binocular spectacle corrected and PM VA were -0.05 Ϯ 0.07 and -0.01 Ϯ 0.03 logMAR for distance photopic, 0.10 Ϯ 0.06 and 0.18 Ϯ 0.05 logMAR for distance mesopic and -0.08 Ϯ 0.06 and 0.02 Ϯ 0.05 logMAR for near photopic, respectively. Statistically significant differences were found between the contrast sensitivity with the two types of correction for both distance and near, with spectacle correction being better in all cases. Conclusion: PureVision multifocal contact lenses preserve good VA and good visual performance under real-life conditions.

The two trifocal intraocular lenses under analysis have modulation transfer function peaks that correspond to the far, intermediate and near focal points. For larger pupil sizes, the FineVision seems to provide better results at far focal points, while the AT LISA tri 839MP not only provides better results at the intermediate and near focal points, but is also less pupil size-dependent.

Both simultaneous vision multifocal CLs provided adequate distance visual quality under photopic and mesopic conditions, and better visual acuity was provided under mesopic conditions for the Purevision lens. Both lenses provided adequate visual performance at intermediate distance, but the near visual acuity appears to be insufficient for early presbyopes who require a moderately demanding near visual quality.