Higher order aberration measurement comparison between Scheimpflug and dual-Scheimpflug technology

Session Details

Session Title: Advanced Tools for Outcome Assessment

Session Date/Time: Tuesday 17/09/2019 | 08:30-10:30

Paper Time: 08:30

Venue: Free Paper Forum: Podium 4

First Author: : A.Piccinini BRAZIL

Co Author(s): :    O. Golan   E. Torres-Netto   F. Hafezi   J. Randleman                    

Abstract Details

Purpose:

To compare the difference and agreement of total corneal higher-order aberrations (HOAs) measurements in normal and keratoconic eyes using Scheimpflug and Dual Scheimpflug/Placido imaging systems.

Setting:

1. Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA

Methods:

105 healthy eyes screened for refractive surgery were evaluated, sequentially, by Scheimpflug and Dual Scheimpflug/Placido devices. Differences, correlations, and agreement (95% limits of agreement (LOA)) between values for total root mean square (RMS), trefoil, coma, and spherical aberration (SA) were analyzed and Bland-Altmann plots were generated. After this initial comparison, 50 eyes screened and diagnosed with keratoconus were used to perform the same evaluation of differences, correlations and agreement of total corneal HOAs between these two devices.

Results:

Normal eyes: RMS, coma, and trefoil were significantly different(p<0.001), SA not. Moderate positive correlation (MPC): Trefoil(r=0.475 to 0.652), coma(r=0.574 to 0.651), SA(r=0.483). Strong positive correlation (SPC): RMS(r=0.817). LOA: (0.039 to 0.405)for trefoil, (0.553 to 0.545)for coma, (0.318)for SA, (1.617)for RMS. Keratoconic eyes, significantly different between groups(p<0.05): trefoil at 30 degress, SA, RMS. Trefoil at 0 degree and total coma values were not. Weak positive correlation(WPC): trefoil at 0 degree(r=0.228). MPC: trefoil at 30 degress(r=0.473), horizontal coma(r=0.430), RMS(r=0.637). SPC: vertical coma(r=0.816), SA(r=0.874). LOA: (1.944 to 2.424)for trefoil, (3.495 to 2.124)for coma, (1.229)for SA and for (10.422)for RMS.

Conclusions:

Scheimpflug and Dual-Scheimpflug/Placido imaging devices generated statistically different values for total cornea higher-order aberrations for normal and keratoconic eyes. While correlation between devices were moderate to strong and a reasonable agreement were found in normal eyes, keratoconic eyes showed limited correlations and wide limits of agreement. Based on these findings, the devices could be reasonably interchangeable for clinical use in normal eyes, but we do not recommend using measurements from these technologies interchangeably when assessing HOAs in eyes with keratoconus.

Financial Disclosure:

None