Tolerance to decentration of biaspheric intraocular lenses with refractive phase-ring extended depth of focus and diffractive trifocal designs

Abstract

Purpose: This study aimed to investigate the in vitro tolerance to decentration of biaspheric intraocular lens (IOLs) with refractive phase-ring extended depth-of-focus (EDOF) and diffractive trifocal designs.

Methods: This experimental study was carried out at the Department of Optics and Optometry and Vision Science, University of Valencia, Spain. The modulation transfer function (MTF) of the ETLIO130C EDOF and the TFLIO130C trifocal IOLs (AST Products Inc., Billerica, MA, USA) were determined at different levels of decentration for a given wavelength and pupil diameter using the PMTF optical bench (Lambda-X Ophthalmics, Nivelles, Belgium). The modulation transfer function (MTF) curves, the through-focus MTF curves, and the Strehl ratios were measured at 3-mm pupil aperture for 0.25-, 0.50- and 0.75-mm decentration.

Results: The optical design of the trifocal TFLIO130C IOL is robust to small decentrations, with virtually no change in MTF response for 0.25 mm decentration. For greater decentration levels, the MTF response is slightly reduced with increasing decentration. The ETLIO130C EDOF design is robust to decentration, as the MTF response is only minimally affected when increasing the decentration up to 0.75 mm.

Conclusions: MTF responses are slightly reduced with greater levels of decentration, but the range of focus provided by both trifocal and EDOF designs are preserved. The effects for average levels of decentration reported in the literature are minimum for both IOL designs.

Keywords: EDOF IOL; In vitro; Optical bench; Optical quality; Presbyopia correcting IOL; Trifocal IOL.

Fig. 1

Schematic diagram of the PMTF optical device

Fig. 2

MTF measurements for the far (upper), intermediate (medium), and near (lower) foci of the trifocal IOL with the lens centered (blue line), and 0.25 (green line), 0.50 (orange line), and 0.75 mm (yellow line) decentration levels. Black dotted line represents the diffraction-limited response MTF

Fig. 3

Through-focus MTF curve for a spatial frequency of 50 cy/mm for the trifocal IOL centered (blue line), and for 0.25 (green line), 0.50 (orange line), and 0.75 mm (yellow line) decentration levels

Fig. 4

MTF measurements for the far (upper), intermediate (medium), and near (lower) foci of the EDoF IOL with the lens centered (blue line), and 0.25 (green line), 0.50 (orange line), and 0.75 mm (yellow line) decentration levels. Black dotted line represents the diffraction-limited response MTF

Fig. 5

Through-focus MTF curve for a spatial frequency of 50 cy/mm for the EDoF IOL centered (blue line), and for 0.25 (green line), 0.50 (orange line), and 0.75 mm (yellow line) decentration levels