Optical Quality After In Vitro Intraocular Lens Power Adjustment Using a Femtosecond Laser

Abstract

Purpose : The aim of this study was to evaluate intraocular lens (IOL) power, modulation transfer function (MTF), light transmission, as well as light scattering of commercially available IOLs before and after different types of adjustment by femtosecond laser. The use of a femtosecond laser to alter the hydrophilicity of targeted areas within an IOL creates the ability to build a refractive index shaping lens within an existing IOL.

Methods : Ten commercially available single-piece, hydrophobic acrylic yellow IOLs, as well as commercially available clear (non-yellow) hydrophobic acrylic monofocal and multifocal IOLs were used in this study. The 10 yellow lenses underwent power adjustment targeted at -2.0 D. The non-yellow monofocal lenses underwent refractive and multifocal adjustments, while the multifocal lenses underwent multifocality cancellation. IOL power and MTF were measured with a Lambda-X PMTF device. Light transmission was measured using a PerkinElmer Lambda 35 UV/Vis spectrophotometer. Back light scattering was assessed with a Scheimpflug camera, at the anterior and posterior surfaces, as well as within the IOL substance.

Results : After laser adjustment, a mean power change of -2.037 D was associated with a MTF change of -0.064, and a light transmittance change of -1.4% in the 10 yellow lenses. Back light scattering increased within the lens in the zone corresponding to the laser treatment at levels not expected to cause any clinical impact. Refractive and multifocal adjustments of non-yellow monofocal lenses were also precise and associated with minimal changes of the optical parameters evaluated. Cancellation of the multifocality of a commercially available multifocal IOL could be obtained with improvement of the MTF.

Conclusions : Power adjustment of commercially available hydrophobic lenses by femtosecond laser produces an accurate change in dioptric power while not significantly affecting the quality of the IOL optic, as assessed by MTF, light transmission, and light scattering measurements.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.