Optical characterization and through-focus performance of two advanced monofocal intraocular lenses

To compare the refractive power profile, subjective depth-of-field and objective optical quality of two advanced monofocal intraocular lenses (IOLs) designed to improve intermediate vision.

This prospective study evaluated forty-six eyes of twenty-three patients, aged 54-68 years, binocularly implanted with two monofocal enhanced intraocular lenses (IOLs), the Tecnis Eyhance and the Physiol Isopure. Subjective through-focus visual acuity curves were obtained by placing trial lenses in front of the eye while wearing its best spherical-cylindrical correction for distance. Objective optical quality was defined as the area under the modulation transfer function, calculated from the wavefront maps measured with a high-resolution aberrometer. The optical design of both lenses was compared based on their refractive power profiles measured with the lenses immersed in saline solution.

Both lenses have progressive aspherical geometries, in which the sagittal power decreases rapidly from the center to the edge of the optical zone. Mean monocular through-focus curves show a best corrected distance visual acuity of - 0.02 logMAR with both lenses. Through-focus visual acuity was marginally higher for the Eyhance, with a difference of 1 letter at the defocus position of - 0.5D and 3 letters between - 1.0D and - 2.0D. Objective assessment of optical quality revealed only a difference of about 2 points in MTF area at distance.

Both IOLs use a similar approach to improve intermediate vision. The Eyhance showed marginally better subjective performance than the Isopure at the target vergences between - 1.00D and - 2.00D, although these results did not reach statistical significance and were not replicated by the objective findings.