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Comparison of internal and total optical aberrations for 2 aberrometers: iTrace and OPD scan.

Won JB, Kim SW, Kim EK, Ha BJ, Kim TI - Korean J Ophthalmol (2008)

Bottom Line: Aberrations of internal optics and total aberrations were compared for the two aberrometers.These results suggest that in healthy eyes, the two aberrometers may vary in some details.The aberrometers showed more agreement at a pupil diameter of 6 mm compared to 4 mm.

View Article: PubMed Central - PubMed

Affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.

ABSTRACT

Purpose: To compare and evaluate the total and internal aberrations measured by two aberrometers: the laser ray tracing aberrometer (iTrace, Tracey Technology) and the automatic retinoscope aberrometer (OPD Scan, Nidek).

Methods: A total of 54 healthy eyes were enrolled in the study. Following pupil dilation, aberrations were measured with the iTrace and OPD Scan. We compared the aberrations obtained from measurements obtained at pupillary diameters of 4 mm and 6 mm with the OPD Scan and iTrace. Aberrations of internal optics and total aberrations were compared for the two aberrometers. For each aberrometer and each eye, the averaged Zernike data were used to calculate various root-mean-square (RMS) data. These parameters, together with the refractive parameters, were then analyzed and complimented by paired t-tests.

Results: At a pupil diameter of 4 mm, the number of total aberrations in the entire eye showed significant differences for the mean values of spherical aberrations (Z4,0) obtained with the OPD Scan and iTrace aberrometers (p=0.001). Aberrations of the internal optics showed significant differences in the mean values of total RMS, coma (Z3,-1), and trefoil (Z3,3) between the iTrace and OPD Scan (p<0.001, p=0.01, p<0.001) for the same pupil diameter of 4 mm. At a pupil diameter of 6 mm, the two instruments showed a similar number of total aberrations. Aberrations of the internal optics showed significant differences in the mean values of total RMS, spherical aberration (Z4,0), and coma (Z3,-1) between the two devices (p<0.001, p=0.01, p<0.001).

Conclusions: The iTrace and OPD Scan showed the largest number of differences for aberrations of internal optics rather than total aberrations for both pupil diameters. These results suggest that in healthy eyes, the two aberrometers may vary in some details. The aberrometers showed more agreement at a pupil diameter of 6 mm compared to 4 mm.

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4.0 mm pupil diameter, Total aberration.
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Figure 1: 4.0 mm pupil diameter, Total aberration.

Mentions: At a pupil diameter of 4.0 mm, measuring total aberration of the entire eye yielded similar coefficients of variation for the two aberrometers, with the exception of the fourth order spherical aberration (Z4,0) (p<0.001) (Table 1, Fig. 1). Comparing the internal optic aberration at a pupil size of 4.0 mm, the mean values of total RMS (p<0.001), 3rd order aberration, coma (Z3,-1) (p=0.01), and trefoil (Z3,3) (p<0.001) showed significant differences between the iTrace and OPD Scan, as shown in Table 2 and Fig. 2.


Comparison of internal and total optical aberrations for 2 aberrometers: iTrace and OPD scan.

Won JB, Kim SW, Kim EK, Ha BJ, Kim TI - Korean J Ophthalmol (2008)

4.0 mm pupil diameter, Total aberration.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2629919&req=5

Figure 1: 4.0 mm pupil diameter, Total aberration.
Mentions: At a pupil diameter of 4.0 mm, measuring total aberration of the entire eye yielded similar coefficients of variation for the two aberrometers, with the exception of the fourth order spherical aberration (Z4,0) (p<0.001) (Table 1, Fig. 1). Comparing the internal optic aberration at a pupil size of 4.0 mm, the mean values of total RMS (p<0.001), 3rd order aberration, coma (Z3,-1) (p=0.01), and trefoil (Z3,3) (p<0.001) showed significant differences between the iTrace and OPD Scan, as shown in Table 2 and Fig. 2.

Bottom Line: Aberrations of internal optics and total aberrations were compared for the two aberrometers.These results suggest that in healthy eyes, the two aberrometers may vary in some details.The aberrometers showed more agreement at a pupil diameter of 6 mm compared to 4 mm.

View Article: PubMed Central - PubMed

Affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.

ABSTRACT

Purpose: To compare and evaluate the total and internal aberrations measured by two aberrometers: the laser ray tracing aberrometer (iTrace, Tracey Technology) and the automatic retinoscope aberrometer (OPD Scan, Nidek).

Methods: A total of 54 healthy eyes were enrolled in the study. Following pupil dilation, aberrations were measured with the iTrace and OPD Scan. We compared the aberrations obtained from measurements obtained at pupillary diameters of 4 mm and 6 mm with the OPD Scan and iTrace. Aberrations of internal optics and total aberrations were compared for the two aberrometers. For each aberrometer and each eye, the averaged Zernike data were used to calculate various root-mean-square (RMS) data. These parameters, together with the refractive parameters, were then analyzed and complimented by paired t-tests.

Results: At a pupil diameter of 4 mm, the number of total aberrations in the entire eye showed significant differences for the mean values of spherical aberrations (Z4,0) obtained with the OPD Scan and iTrace aberrometers (p=0.001). Aberrations of the internal optics showed significant differences in the mean values of total RMS, coma (Z3,-1), and trefoil (Z3,3) between the iTrace and OPD Scan (p<0.001, p=0.01, p<0.001) for the same pupil diameter of 4 mm. At a pupil diameter of 6 mm, the two instruments showed a similar number of total aberrations. Aberrations of the internal optics showed significant differences in the mean values of total RMS, spherical aberration (Z4,0), and coma (Z3,-1) between the two devices (p<0.001, p=0.01, p<0.001).

Conclusions: The iTrace and OPD Scan showed the largest number of differences for aberrations of internal optics rather than total aberrations for both pupil diameters. These results suggest that in healthy eyes, the two aberrometers may vary in some details. The aberrometers showed more agreement at a pupil diameter of 6 mm compared to 4 mm.

Show MeSH
Related in: MedlinePlus