Corneal Topographic and Aberrometric Measurements Obtained with a Multidiagnostic Device in Healthy Eyes: Intrasession Repeatability

Abstract

Purpose. To evaluate the intrasession repeatability of corneal curvature, eccentricity, and aberrometric measurements obtained with a multidiagnostic device in healthy eyes. Methods. This study enrolled 107 eyes of 107 patients ranging in age from 23 to 65 years. All of them underwent a complete anterior segment examination with the VX120 system (Visionix-Luneau Technologies, Chartres, France). Three consecutive measurements were obtained. The within-subject standard deviation (Sw), intrasubject precision (1.96 × Sw), and intraclass correlation coefficient (ICC) were calculated. Results. All Sw for corneal power measurements were below 0.26 D, with ICC above 0.982. The Sw for corneal astigmatism at different areas (3, 5, and 7 mm) was below 0.21 D, with ICC above 0.913. Concerning the axis of astigmatism, its Sw was below 11.27°, with ICC above 0.975. The Sw and ICC for corneal eccentricity were 0.067 and 0.957, respectively. The Sw and ICC for high-order aberration root mean square (RMS) were 0.048 µm and 0.901, respectively. For 3rd- and 4th-order aberrometric parameters, all Sw were below 0.037 µm and all ICC were higher than 0.84, except for quadrafoil RMS (ICC: 0.689). Conclusions. The multidiagnostic device evaluated is able to provide consistent measurements of corneal power, eccentricity, and third- and fourth-order aberrations in healthy eyes.

Validation of refraction and anterior segment parameters by a new multi-diagnostic platform (VX120)

“…The LoAs found were also acceptable, with values from −0.12 to 0.13 mm (or ±0.12) and from −0.08 to 0.09 mm (or ±0.09) mm for K1 and K2, respectively, which are similar and even smaller than those reported in other studies comparing technologies of measurement of corneal curvature. 3 , 22 , 25 , 26 , 27 , 28 Piñero et al (2017) 4 found similar results when they evaluated the intrasession repeatability of keratometry measurements for the VX120. These authors obtained Sw below 0.26 D for keratometric measurements, with ICC above 0.982.…”

“…The VX120 (Visionix Luneau, Chartres, France) is new non-invasive multi-diagnostic platform that combines refraction (Hartmann–Shack based autorefractometer), 2 , 3 simulated keratometry (based on Placido disk videokeratography), 3 , 4 non-invasive stationary Scheimpflug based pachymetry and Hartmann–Shack wavefront aberrometry as well as other functions not investigated in this study. 4 , 5 …”

“…Piñero et al (2017) 4 evaluated the intra-test repeatability of several functions of the VX120 system in 107 healthy subjects and found that the device provides consistent measurements of keratometric measurements, corneal eccentricity, and third- and fourth-order corneal aberrations. Likewise, the same research group has demonstrated recently that the VX120 system is also able to provide consistent measurements of anatomical parameters of the anterior segment, such as anterior chamber depth, central and peripheral pachymetry and iridocorneal angle.…”

The normal distribution of corneal eccentricity and its determinants in two rural areas of north and south of Iran

“…5 According to previous studies, eccentricity can be a diagnostic factor for the early diagnosis of keratoconus in its primary stages, and it has been suggested that eccentricity increases before slit-lamp signs appear. 3 Some studies suggest that the eccentricity value in normal adult population is from 0.4 to 0.6, 6 , 7 , 8 , 9 but it can be greater than 0.8 in keratoconus patients. 3 According to the available literature, this index also has significant implications for refractive surgery.…”

“…There are few studies concerning E-value and its relationship with age, gender, refractive errors, central corneal thickness, and anterior chamber depth (ACD), and as mentioned, all studies have been restricted to a limited age range. 7 , 8 , 9 , 11 , 12 This study was conducted to determine the normal range of eccentricity in a wide age range and examine its relationship with demographic variables, refractive errors, and a number of anterior segment parameters.…”