Adaptive Optics Simulation of Intraocular Lenses with Modified Spherical Aberration

Investigative Ophthalmology and Visual Science
Patricia A. Piers, Enrique J. Fernandez, Silvestre Manzanera, Sverker Norrby and Pablo Artal

Purpose: Adaptive optics systems can be used to investigate the potential visual benefit associated with correcting ocular wavefront aberration. In this study, adaptive optics techniques were used to evaluate the potential advantages and disadvantages associated with intraocular lenses (IOLs) with modified spherical aberration profiles.
Methods: An adaptive optics vision simulator was constructed that allows psychophysical tests to be performed while viewing targets through any desired ocular wave-front profile. With this simulator, the subjective visual performance of four subjects was assessed by letter acuity and contrast sensitivity (at 3, 6, and 15 cyc/deg) for two different values of induced spherical aberration. The values of spherical aberration were chosen to reproduce two conditions: the average amount measured in pseudophakic patients with implanted IOLs having spherical surfaces and the complete correction of the individual’s spherical aberration. Visual performance was assessed in both white and green light, at best focus and for defocus of +-0.5 and +-1.0 D.
Results: There was an average improvement in visual acuity associated with the correction of spherical aberration of 10% and 38% measured in white and green light, respectively. Similarly, average contrast sensitivity measurements improved 32% and 57% in white and green light. When spherical aberration was corrected, visual performance was as good as or better than for the normal spherical aberration case for defocus as large as +-1 D.
Conclusions: Correcting ocular spherical aberration improves spatial vision in the best-focus position without compromising the subjective tolerance to defocus.