Exploring The Effect Of Corneal Spherical Aberration And Chord µ On Depth Of Focus With A Non-Diffractive Enhanced Monofocal Intraocular Lens (A Pilot Study).

To evaluate effect of corneal spherical aberration and chord µ on visual performance and depth of focus with an enhanced monofocal intraocular lens (IOL). Chord μ describes the linear distance from the pupil's center to the point where the visual axis intersects the cornea, while the kappa angle measures the angular discrepancy between the visual axis and the pupillary axis. These metrics are closely linked in their ability to characterize the spatial relationship between the eye's optical center and the pupil center. A high value in either measurement may indicate a deviation from the ideal optical axis and  a potential impact on postoperative visual outcomes.

Citadelle Hospital, Liège, Belgium, Ophthalmoogy Department

In this retrospective study patients implanted with RayOne EMV IOL or RayOne EMV Toric (Rayner) lens were included. All surgeries and all analysis were performed by a single surgeon (FXC). Between 2 and 4 months after the surgery, we evaluated monocular distance corrected visuals acuities (VAs) at distance (CDVA), intermediate (DCIVA) and near (DCNVA). We also evaluated best corrected defocus curve from +1.0 to -2.5D monocularly. We calculated correlation between visual performance and preoperative corneal spherical aberration (SA) (Z40), , manifest refraction spherical equivalent (MRSE), postoperative MRSE and age. Corneal SA (Total Corneal Refractive Power Z40) and chord µ were measured with Pentacam AXL device (OCULUS, Germany).

50 eyes from 28 patients met the inclusion criteria and were analyzed. Mean patient age was 75±8.8 ranging from 57 to 90 years. Preoperative SA was 0.39±0.39 µm (-0.08 to 2.46) and chord µ was 0.28±0.12 (0.09 to 0.62).  Preoperative MRSE was 0.42±2.99 D (-9.25 to +). Postoperative MRSE was -0.38±0.5 D (-1.5 to +0.5 D).Monocular CDVA, DCIVA and DCNVA were -0.07±0.08 logMAR, 0.37±0.1 logMAR and 0.61±0.13 logMAR, respectively. In the monocular distance corrected defocus curve analysis the VAs at -1.0 D, -1.5 D and -2.0 D were 0.16±0.12 logMAR, 0.31±0.13 and 0.45, respectively. No correlation was found between visual acuities and chord µ or SA. A weak association (Pearson r= 0.51) between age and CDVA was observed.

In our study, visual performance and visual acuities at intermediate and near vision are not predicted by preoperative corneal spherical aberration and chord µ measured by Pentacam AXL.