Purpose: Current intraocular lenses (IOLs) are usually based in a single lens design. A proper selection of the lens’ surfaces characteristics allows for adequate defocus, astigmatism and spherical aberration correction. However, with a single lens, perfect image quality cannot be achieved. We explored the potential of an intraocular lens doublet for a more complete correction of the optical aberrations in pseudophakic eyes.
Methods: Ray-tracing techniques were used to optimize the optical performance of different configurations of IOL doublets within an eye model. The analysis was performed in white light to consider chromatic aberration correction. The model incorporated chromatic dispersion data from the ocular media and IOL standard materials as acrylics and silicone. Iterative optimization algorithms were applied to design the different doublet configurations to correct for longitudinal chromatic aberration, spherical aberration and peripheral aberrations within 10 degrees of retinal field.
Results: Full aberration correction was achieved by combining two materials in one doublet IOL, including off-axis aberrations. Chromatic aberration was typically reduced as much as 95 % compared to the value present phakic eyes. The use of aspheric surfaces permitted to obtain near diffraction-limited image quality on an extended range around the optical axis of 10 degrees. Lateral color and sphero-chromatic aberration were also largely reduced as compared with the phakic normal eye, and also compared with the pseudophakic eye implanted with a standard IOL. A tolerance analysis of the impact of biometrical parameters after surgery was also performed. The benefits in optical quality of the doublet IOL were maintained within a reasonable range of values of decentering and tilt.
Conclusions: The potential of an IOL doublet to provide full aberration correction after cataract surgery has been analyzed. By using two materials within an IOL and combining with proper aspheric surfaces, chromatic and peripheral aberrations can be corrected. While an improvement in image quality should provide patients with a better quality of vision, the practical application of doublets IOL should be further explored in terms of manufacturing and surgical limitations.