Study On Intra-Ocular Lens Aberration Measurement In-Air

In clinical ophthalmology, the wavefront aberration of human eyes is expressed by Zernike polynomial after cataract surgery and intraocular lens implantation, the human eyes aberration will change. The problem of objective evaluation of wavefront aberration introduced by the Intra-ocular (IOL) in-vivo remains unsolved. This paper introduced the measurement principal of IOL wavefront aberration with expression by Zernike polynominal in air. A Hartmann-Shack wavefront sensor system was constructed to measure the wavefront of IOL and to get the corresponding grid patterns. After a series of computer image processing steps, 7th order with 35 items Zernike coefficients was obtained. The IOL of 20.0D power was measured 5 times by this system to get the spherical aberration about 6.73 +/- 0.02 mu m, demonstrating the good repeatability of the system. Ten IOLs with the same 20.0D power but difference in surface curvature were chosen for measurement. The spherical aberration observed were in the range of 2.74 mu m-11.26 mu m. These results are valuable for the optical design of IOLs and the aberration analysis of human eyes post-operation.