Abstract
Purpose::
We investigated the optical properties of the foldable intraocular lens (F-IOL) within an ISO model eye using experimental in-the-bag fixation to evaluate the possibility that the F-IOL optic in the capusular bag can deform due to repulsion forces from the haptics, and that the induced deformation can cause degradation of the optical properties of the lens.
Methods::
Each F-IOL compressed into a 10 mm diameter was fixed in an ISO model eye filled with BSS at 35°C. We then measured the modulation transfer function (MTF) and refractive power of the ISO model eye containing the F-IOL. We expected to induce astigmatism, so we also measured the optical properties of each axis. We used the following F-IOL, with a power of +20.0D: MA60AC (Alcon), AR40e (AMO), YA-66BB (HOYA), AQ-310NV (Canon-STAAR) and AN6 (Menicon).
Results::
The measured MTF difference of each lens was as follows: AN6 (3%), MA60AC (35%), AR40e (4%), YA-60BB (3%), AQ-310NV (2%). The surface curvature of all of the IOLs, except for the MA60AC, did not remarkably change, as the MTF and refractive power were nearly the same for all axes. However, the MA60AC had the largest difference between the maximum and minimum measured MTF. From this result we concluded that the MTF of its optic was uneven and that toricity in the surface was induced by the compression. It can be suggested that the MA60AC optic underwent some deformation by compression of the haptics.
Conclusions::
It is very important to consider the balance between optic and haptics when designing F-IOLs.
Keywords: intraocular lens • optical properties • refraction