Abstract
We investigated whether eyes with keratoconic corneal tomography pattern could benefit more from aberration correction with custom intraocular lenses (IOLs) than normal cataractous eyes despite the effect of misalignment on the correction of aberrations. Custom IOLs (cIOLs) were calculated for twelve normal and twelve keratoconic eyes using personalized numerical ray tracing models. The Stiles-Crawford weighted root-mean-square spot-size (wRMS) at the virtual fovea was evaluated for cIOLs and aberration-neutral IOLs (nIOLs) in a simulated clinical study with 500 virtual IOL implantations per eye and per IOL. IOL misalignment (decentration, tilt, rotation) and pupillary ectopia (4.5 mm iris aperture) were varied upon each virtual implantation. The nIOLs achieved average wRMS of 16.4 ± 4.3 μm for normal, and 92.7 ± 34.4 μm for keratoconic eyes (mean ± standard deviation). The cIOLs reduced the average wRMS to 10.3 ± 5.8 μm for normal, and 28.5 ± 18.6 μm for keratoconic eyes. The cIOLs produced smaller wRMS than nIOLs in most virtual implantations (86.7% for normal and 99.4% for keratoconic eyes). IOL misalignment resulted in larger wRMS variations in the keratoconus group than in the normal group. Custom freeform IOL-optics-design may become a promising option for the correction of advanced aberrations in eyes with non-progressive keratoconic corneal tomography pattern.
Highlights
Cataract is characterized by the natural human lens becoming opaque leading to significant loss of vision[1]
We investigate the potential benefit of custom intraocular lenses (IOLs) for normal cataractous eyes and keratoconic eyes for monochromatic light in the presence of IOL misalignment to determine if eyes with nonprogressive keratoconic corneal tomography pattern could benefit more from aberration correction with custom IOLs than normal cataractous eyes
To illustrate the IOL optimization and the effect of IOL misalignment on the Stiles-Crawford weighted root-mean-square spot-size, the results of two left eyes are shown in detail: One (NP) belongs to the normal group the other (KP) to the keratoconus group
Summary
Cataract is characterized by the natural human lens becoming opaque leading to significant loss of vision[1] It is treated by surgical removal of the lens and subsequent replacement with an artificial intraocular lens (IOL). Numerical ray tracing can be used to choose the IOL’s refractive power[2,3,4] and cylinder[5] accurately to achieve low postoperative refractive errors, and to estimate the appropriate asphericity of the IOL6 in order to correct higher order aberrations of the eye. Improvements of postoperative vision might be possible with custom IOLs that correct higher order aberrations in addition to spherical aberration and refractive error (sphere, cylinder). The use of custom IOLs for the correction of advanced corneal refractive errors associated with keratoconus has been suggested[11]. Alternative ways to represent the cornea have been suggested to facilitate the ray tracing analysis of asymmetric corneas[14,18,19,20]
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