J Korean Ophthalmol Soc.  2015 Oct;56(10):1497-1504. 10.3341/jkos.2015.56.10.1497.

Comparison of Corneal Higher-Order Aberrations Measured with Two Instruments Using Scheimpflug Camera System

• Choi YJ
• Kang NH
• Jun RM

• KMID: 2214407
• DOI: http://doi.org/10.3341/jkos.2015.56.10.1497

Abstract

PURPOSE
To compare the corneal higher-order aberrations (HOAs) of normal young subjects using Galilei(TM) G4 (Zeimer, Port, Switzerland) and Pentacam(R) (Oculus Inc., Wetzlar, Germany).
METHODS
Corneal HOAs were measured using Galilei(TM) G4 and Pentacam(R) in 41 healthy individuals (41 eyes). Intraclass correlation coefficients (ICCs) were obtained to evaluate the repeatability of the 2 devices. Differences in HOAs between the 2 instruments were analyzed with a paired t-test and correlations evaluated.
RESULTS
All ICCs measured using Galilei(TM) G4 and Pentacam(R) showed more than moderate repeatability (>0.81) except trefoil, tetrafoil, 4th and 5th HOAs. When comparing the measurements obtained with Galilei(TM) G4 and Pentacam(R), total HOAs, spherical aberration (SA), secondary astigmatism and 5th total HOAs were statistically significantly different between the 2 device (all p < or = 0.001). In addition, Galilei(TM) G4 and Pentacam(R) showed discrepancy among all corneal HOAs items. Although the total corneal HOAs and the SA were significantly correlated, other HOA measurements generally exhibited a low correlation.
CONCLUSIONS
Corneal HOAs obtained by the 2 instruments cannot be used interchangeably due to their differences and discrepancy although corneal HOAs measured using Galilei(TM) G4 and Pentacam(R) showed relatively high repeatability.

Keyword

Corneal higher-order aberrations; Galilei(TM) G4; Pentacam(R)

MeSH Terms

Astigmatism
Lotus

Figure

• 

  Figure 1. Bland-Altman plots showing the agreement between mean corneal aberrometers (μ m) obtained by the 2 tomography de-vices: Galilei TM G4 and Pentacam®. (A-F) graphs plot the difference against the average of two measurements of corneal HOAs, with 95% limits of agreement (broken lines) and the mean difference (black line). (A) Total corneal HOAs, (B) Coma, (C) Trefoil, (D) Spherical aberration, (E) Secondary astigmatism, (F) Tetrafoil. HOAs = higher-order aberrations; SA = spherical aberration; 2° astig = secondary astigmatism.

• 

  Figure 2. Correlations of measurements of corneal aberration using Galilei TM G4 and Pentacam®. (A-F) Shows measurements of total corneal HOAs using Galilei TM G4 against Pentacam® measurements. (A) Total corneal HOAs, (B) Coma, (C) Trefoil, (D) Spherical aberration, (E) Secondary astigmatism, (F) Tetrafoil. HOAs = higher-order aberrations; SA = spherical aberration; 2° astig = sec-ondary astigmatism; r = Pearson correlation coefficient. * Statistically significant ( p-value < 0.05, based on t-test).

Reference

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