Assessment of Diffractive Intraocular Lenses Using Near-Infrared Light: A Critical Evaluation

After cataract surgery, near-infrared (NIR) light-based optical devices are commonly used for in vivo vision quality assessment, using wavefront sensors and double-pass techniques. This study investigates the diffraction efficiencies and orders of the AT LISA tri 839MP (Carl Zeiss Meditec AG, Berlin, Germany) under visible and NIR illumination, highlighting challenges in using NIR-based devices to evaluate diffractive intraocular lenses (IOLs).

This study uses an optical bench system to generate in vitro through focus intensity data and compares the results to an optics simulation using the manufacturer's theoretically designed diffractive surface topography of the investigated trifocal IOL instead of possibly error-prone measured topography data.

For visible light, through-focus curve intensities and energy efficiencies behaved as expected. However, under NIR light, near and intermediate foci showed significantly reduced intensities compared to the far focus. Energy efficiency measurements indicate suboptimal performance of the near and intermediate foci with NIR light. Under these conditions, the investigated trifocal IOL became almost monofocal.

The study demonstrates the wavelength-dependent behavior of the diffractive IOL, emphasizing the risks of inaccurate assessments when using NIR-based devices. It highlights the need for visible-light-based techniques for accurate evaluation and the importance of using precise surface topography data in simulations.

This research bridges the gap between basic research and clinical care by showing that vision assessments performed with NIR-light inaccurately evaluate diffractive IOLs, guiding clinicians toward visible-light techniques for accurate vision assessment.