Manipulating ocular longitudinal chromatic aberration (LCA) can enhance visual outcomes in presbyopia-correcting multifocal intraocular lenses and serve as a powerful tool for investigating eye growth mechanisms. This study introduces a spatial light modulator-based visual simulator (SLMVS) that utilizes the unique properties of diffractive optics with a negative Abbe number to precisely control ocular LCA, allowing for its correction or reversal. The system was validated through optical bench tests using a model eye and human subjects. Bench test results under polychromatic light showed improved image quality close to monochromatic performance when LCA was corrected at the far focus of both monofocal and trifocal lenses. In human tests, the SLMVS achieved a mean LCA correction of 0.01 ± 0.13 D and a mean LCA reversal of -1.62 ± 0.40 D, compared to an average ocular LCA of 1.41 ± 0.25 D.