Purpose:
Intraocular lenses (IOLs) are theoretically designed to produce retinal images with a high quality for object placed at one or more distances. However, oftenly, visual performances after surgery (specially IOLs with aspheric designs) are limited by descentrations and/or tilts. We have studied, in vitro, the optical quality of several IOLs with a new device.
Methods:
A comercial aberrometer (Imagine Eyes irx3) together with a new device which consist on an artificial eye was used to obtain the in vitro wavefront in monofocal and multifocal IOLs after subtrating the aberrations of the artificial eye. The artificial eye has the possibiliy to produce a descentration, rotation and/or a tilt in relation to the artificial cornea. From the wavefront outcomes we obtained several optical quality metrics such us the PSF or the MTF. The aberrometer used also allows obtaining wavefront measurement for different object possitons and different pupil sizes simulating near vision performance for multifocal IOLs. Repeatability and exactitude of the system was tested comparing its results with computer simulations on a model eye.
Results:
Repited measurements on an IOL for a 5 mm pupil show a standard deviation in all Zernikes coefficients (up to 8th-order) always less that 0.01 microns except in the case of defocus for which standard deviation was 0.06 microns (about 0.07 D). In vitro measurement of the IOL differs in less than 0.01 D respect the optical simulations generated by the model eye. The figure represents a typical in vitro wavefront of a multifocal IOLs with a vertical decentration of 0.3 mm. Astigmatism and higher-order aberrations, specially coma, was generated after tilting and decentering the IOL.
Conclusions:
A new device was tested and used to measure in vitro optical performance of IOLs. The system may be used to predict tolerances of diferent IOLs under possible rotations and translations before the surgery.
Keywords: intraocular lens • optical properties • aberrations