Abstract
Purpose::
To establish the relationship between the optical and visual performance of eyes implanted with multifocal IOLs.
Methods::
Corneal topography, axial length and keratometry were measured for 46 individual cataract patients included in a clinical trial and used to assemble 46 individual white light eye models. These models have been verified in a previous study.Spherical monofocal and multifocal IOLs were implanted in these eye models. The IOL power was chosen using the SRK/T formula and an A-constant that was optimized for the set of 46 eyes. Then, each eye was refracted for sphere and cylinder in steps of 0.25 diopter, using the volume under the MTF curve as a criterion for best refraction.Next, for the monofocal group, the through focus radial MTF was calculated and the area under the curve was compared with clinically measured through focus contrast sensitivity of pseudophakic patients, implanted with monofocal IOLs.For the multifocal group, the visual acuity was estimated as the intersection of the radial MTF curve and a neural threshold curve. The values were compared to clinically established data.
Results::
The refraction procedure of the eye models resulted in an average refraction of 0.06D, with a mean absolute error (MAE) of 0.55D. The MAE is consistent with clinical data (e.g. Findl et al. 2001).The through focus performance of the eye models with the monofocal IOLs, as described by the area under the radial MTF curve correlated well with clinically measured through focus contrast sensitivity curves.The through focus performance of the eye models with the multifocal IOLs, as described by the intersection of the radial MTF curve with a neural threshold correlated well with clinically measured through focus visual acuity curves.
Conclusions::
The through focus contrast sensitivity and visual acuity of pseudophakic patients implanted with monofocal or multifocal IOLs correlates well with the optical performance parameters in clinically verified eye models.
Keywords: intraocular lens • visual acuity • computational modeling