Abstract
Purpose: :
To improve the metrics generated from defocus curves used to evaluate multifocal intraocular lenses (IOLs).
Methods: :
Seventy-five patients were binocularly implanted with five different designs of multifocal IOLs: Concentric fully diffractive, concentric refractive, sectorial refractive, combination of refractive and diffractive or with monofocal IOLs. Monocular and binocular defocus curves from +1.5D to -5.0D in 0.5D randomised steps were measured. The area of focus (AoF) was calculated as the integrated area under the curve with limits of +0.50 to -0.50 D for distance, -0.50 to -2.00 D for intermediate and -2.00 to -4.00 for near. Traditional Depth of Focus (DoF) was calculated using both relative and absolute acuity criteria. Near and intermediate vision were also subjectively graded on a Likert scale.
Results: :
The defocus curve data was best fitted using a 9th order polynomial (r2=0.98±0.02). Relative DoF did not differentiate between the IOL groups (F4=2.2, p=0.08). Absolute DoF differentiated between the multifocal and monofocal IOL groups (f4=10.1, p<0.001), but not between the multifocal groups (p>0.05). The AoF differentiated differences between the multifocal IOL groups and between the multifocal and monofocal IOL groups (F4=10.3, p<0.001). The subjective rating of vision demonstrated differences between the multifocal and monofocal groups (F4=10.1, p<0.001).
Conclusions: :
The AoF metric provides detailed information regarding the performance of multifocal IOLs at distance, intermediate and near. The metric is sensitive to differences between multifocal IOL designs unlike traditional relative and absolute acuity defocus curve evaluations.
Keywords: intraocular lens • accommodation