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Comparison of neuroretinal rim area measurements made by the Heidelberg Retina Tomograph I and the Heidelberg Retina Tomograph II.

Wang YX, O'Leary N, Strouthidis NG, White ET, Ho TA, Garway-Heath DF - J. Glaucoma (2013 Oct-Nov)

Bottom Line: For the cross-sectional study, follow-up RA measurements from HRT Classic and HRT II were compared, using the same HRT Classic mean topography as the baseline.The linear rates of RA change were compared in 2 short time series with either an HRT Classic or an HRT II mean topography as baseline, and 4 follow-up HRT II mean topographies.Although HRT software is backward-compatible, follow-up RA measurements made in the same eye using HRT Classic and HRT II devices display statistically and clinically meaningful systematic differences when HRT Classic topographies are used as a baseline.

View Article: PubMed Central - PubMed

Affiliation: *NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology ‡Department of Optometry and Visual Science, City University London, London, UK †Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China §Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, NS, Canada.

ABSTRACT

Purpose: To investigate the agreement between neuroretinal rim area (RA) measurements using the Heidelberg Retina Tomograph I (HRT Classic) and Heidelberg Retina Tomograph II (HRT II). To compare apparent RA changes in follow-up series of HRT II topographies when using either an HRT Classic or HRT II mean topography as baseline.

Design: Cross-sectional study and "no-change," short time series study.

Participants: Forty-three ocular hypertensive and 31 primary open angle glaucoma subjects.

Methods: Five HRT Classic and 5 HRT II examinations were acquired from 1 eye of each subject, across 2 visits within 6 weeks. For the cross-sectional study, follow-up RA measurements from HRT Classic and HRT II were compared, using the same HRT Classic mean topography as the baseline. The linear rates of RA change were compared in 2 short time series with either an HRT Classic or an HRT II mean topography as baseline, and 4 follow-up HRT II mean topographies. Intervals between topographies were arbitrarily set at 1 year for meaningful comparisons of rates. Rates of RA change over time were calculated by linear regression. Separate analyses were performed using 3 available reference planes (RP).

Main outcome measures: Global and sectoral RA measurements in HRT Classic and HRT II mean topographies; linear rates of RA change.

Results: HRT Classic minus HRT II mean differences (95% limits of agreement) were 0.09 (-0.17, 0.35) mm, 0.09 (-0.13, 0.32) mm, and 0.11 (-0.24, 0.46) mm for the Moorfields, 320 µm, and standard RPs, respectively (P<0.001 for all RPs, Wilcoxon rank sum test). In the time series, the mean differences (95% limits of agreement) of RA rates of change (HRT Classic baseline minus HRT II baseline) were -0.01 (-0.06, 0.03) mm/y, -0.01 (-0.06, 0.04) mm/y, and -0.0 (-0.09, 0.05) mm/y using the Moorfields, 320 µm, and standard RPs, respectively.

Conclusion: Although HRT software is backward-compatible, follow-up RA measurements made in the same eye using HRT Classic and HRT II devices display statistically and clinically meaningful systematic differences when HRT Classic topographies are used as a baseline.

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Related in: MedlinePlus

Schematic of examinations and study protocols. For all patients, the 2 visits were within 6 weeks of each other. Every participant underwent 5 HRT Classic tests and 5 HRT II examinations. Examinations 1, 3, and 4 (diamond-shaped) were acquired by ETW; examinations 2 and 5 (ellipse-shaped) were acquired by NGS. A3 and B3 were compared in the cross-sectional part, with A1 as baseline topography. In the longitudinal part, series 1 was composed of A1 as baseline topography and B2 to B5 as follow-up topographies. In the same way, series 2 was composed of B1 as baseline examination, and B2 to B5 as follow-up topographies.
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Figure 1: Schematic of examinations and study protocols. For all patients, the 2 visits were within 6 weeks of each other. Every participant underwent 5 HRT Classic tests and 5 HRT II examinations. Examinations 1, 3, and 4 (diamond-shaped) were acquired by ETW; examinations 2 and 5 (ellipse-shaped) were acquired by NGS. A3 and B3 were compared in the cross-sectional part, with A1 as baseline topography. In the longitudinal part, series 1 was composed of A1 as baseline topography and B2 to B5 as follow-up topographies. In the same way, series 2 was composed of B1 as baseline examination, and B2 to B5 as follow-up topographies.

Mentions: Seventy-four eyes of 74 subjects recruited from the ocular hypertension (OHT) and the adult general glaucoma clinics at Moorfields Eye Hospital were included in a prospective HRT test-retest study reported by Strouthidis et al.14 In brief, 43 eyes with OHT and 31 with primary open angle glaucoma were selected. HRT Classic images and HRT II images were acquired by 2 experienced operators (E.T.W., N.G.S.) on the same date (visit 1), and on a second date (visit 2) within 6 weeks of visit 1. A total of 5 HRT Classic mean topographies and 5 HRT II mean topographies were obtained for each eye. A schematic for the visits and examinations is shown in Figure 1.


Comparison of neuroretinal rim area measurements made by the Heidelberg Retina Tomograph I and the Heidelberg Retina Tomograph II.

Wang YX, O'Leary N, Strouthidis NG, White ET, Ho TA, Garway-Heath DF - J. Glaucoma (2013 Oct-Nov)

Schematic of examinations and study protocols. For all patients, the 2 visits were within 6 weeks of each other. Every participant underwent 5 HRT Classic tests and 5 HRT II examinations. Examinations 1, 3, and 4 (diamond-shaped) were acquired by ETW; examinations 2 and 5 (ellipse-shaped) were acquired by NGS. A3 and B3 were compared in the cross-sectional part, with A1 as baseline topography. In the longitudinal part, series 1 was composed of A1 as baseline topography and B2 to B5 as follow-up topographies. In the same way, series 2 was composed of B1 as baseline examination, and B2 to B5 as follow-up topographies.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222790&req=5

Figure 1: Schematic of examinations and study protocols. For all patients, the 2 visits were within 6 weeks of each other. Every participant underwent 5 HRT Classic tests and 5 HRT II examinations. Examinations 1, 3, and 4 (diamond-shaped) were acquired by ETW; examinations 2 and 5 (ellipse-shaped) were acquired by NGS. A3 and B3 were compared in the cross-sectional part, with A1 as baseline topography. In the longitudinal part, series 1 was composed of A1 as baseline topography and B2 to B5 as follow-up topographies. In the same way, series 2 was composed of B1 as baseline examination, and B2 to B5 as follow-up topographies.
Mentions: Seventy-four eyes of 74 subjects recruited from the ocular hypertension (OHT) and the adult general glaucoma clinics at Moorfields Eye Hospital were included in a prospective HRT test-retest study reported by Strouthidis et al.14 In brief, 43 eyes with OHT and 31 with primary open angle glaucoma were selected. HRT Classic images and HRT II images were acquired by 2 experienced operators (E.T.W., N.G.S.) on the same date (visit 1), and on a second date (visit 2) within 6 weeks of visit 1. A total of 5 HRT Classic mean topographies and 5 HRT II mean topographies were obtained for each eye. A schematic for the visits and examinations is shown in Figure 1.

Bottom Line: For the cross-sectional study, follow-up RA measurements from HRT Classic and HRT II were compared, using the same HRT Classic mean topography as the baseline.The linear rates of RA change were compared in 2 short time series with either an HRT Classic or an HRT II mean topography as baseline, and 4 follow-up HRT II mean topographies.Although HRT software is backward-compatible, follow-up RA measurements made in the same eye using HRT Classic and HRT II devices display statistically and clinically meaningful systematic differences when HRT Classic topographies are used as a baseline.

View Article: PubMed Central - PubMed

Affiliation: *NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology ‡Department of Optometry and Visual Science, City University London, London, UK †Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China §Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, NS, Canada.

ABSTRACT

Purpose: To investigate the agreement between neuroretinal rim area (RA) measurements using the Heidelberg Retina Tomograph I (HRT Classic) and Heidelberg Retina Tomograph II (HRT II). To compare apparent RA changes in follow-up series of HRT II topographies when using either an HRT Classic or HRT II mean topography as baseline.

Design: Cross-sectional study and "no-change," short time series study.

Participants: Forty-three ocular hypertensive and 31 primary open angle glaucoma subjects.

Methods: Five HRT Classic and 5 HRT II examinations were acquired from 1 eye of each subject, across 2 visits within 6 weeks. For the cross-sectional study, follow-up RA measurements from HRT Classic and HRT II were compared, using the same HRT Classic mean topography as the baseline. The linear rates of RA change were compared in 2 short time series with either an HRT Classic or an HRT II mean topography as baseline, and 4 follow-up HRT II mean topographies. Intervals between topographies were arbitrarily set at 1 year for meaningful comparisons of rates. Rates of RA change over time were calculated by linear regression. Separate analyses were performed using 3 available reference planes (RP).

Main outcome measures: Global and sectoral RA measurements in HRT Classic and HRT II mean topographies; linear rates of RA change.

Results: HRT Classic minus HRT II mean differences (95% limits of agreement) were 0.09 (-0.17, 0.35) mm, 0.09 (-0.13, 0.32) mm, and 0.11 (-0.24, 0.46) mm for the Moorfields, 320 µm, and standard RPs, respectively (P<0.001 for all RPs, Wilcoxon rank sum test). In the time series, the mean differences (95% limits of agreement) of RA rates of change (HRT Classic baseline minus HRT II baseline) were -0.01 (-0.06, 0.03) mm/y, -0.01 (-0.06, 0.04) mm/y, and -0.0 (-0.09, 0.05) mm/y using the Moorfields, 320 µm, and standard RPs, respectively.

Conclusion: Although HRT software is backward-compatible, follow-up RA measurements made in the same eye using HRT Classic and HRT II devices display statistically and clinically meaningful systematic differences when HRT Classic topographies are used as a baseline.

Show MeSH
Related in: MedlinePlus