Scan tracking coordinates for improved centering of Stratus OCT scan pattern.

Published

Journal Article

OBJECTIVE: To describe and evaluate a technique to optimize scan centering during the Stratus optical coherence tomography (OCT) image acquisition process using currently available scan tracking coordinates. DESIGN: Observational clinical study. PARTICIPANTS: Twelve eyes of six normal subjects were examined using the Fast retinal nerve fiber layer (RNFL) thickness and the Fast Optic Disc acquisition protocols. METHODS: At visit 1, 3 consecutive measurements (trials) were taken by 2 different operators with the scan subjectively centered on the optic disc for the Fast RNFL thickness protocol and Fast Optic Disc protocol. At visit 2, 3 consecutive measurements were taken by positioning the scan using scan tracking coordinates. The scan coordinates were recorded twice by each operator and the limits of agreement and Bland-Altman plots were used to estimate agreement. The within subjects standard deviation (Sw) and the coefficient of variation (CV) were calculated for RNFL and optic disc parameters for each operator separately and differences by scan positioning method were evaluated using a 3-way (trial x operator x visit) analysis of variance for repeated measures. RESULTS: The Sw and CV for the RNFL thickness parameters were generally higher when the scan was subjectively centered on the disc compared to when using the newly described coordinate system (eg, for operator 2, temporal sector Sw was 1.60+/-0.78 and 4.09+/-0.99 and CV was 2.2% and 5.7% with and without coordinate use, respectively). For the Fast RNFL protocol, the use of scan tracking coordinates resulted in significantly less variability than subjective placement of the scan circle using the landmark feature (currently recommended technique) in the temporal sectors only. No significant difference was found for any of the optic disc parameters. Bland-Altman plots showed good agreement within each operator for calculating scan coordinates suggesting this technique is reproducible. CONCLUSIONS: Reproducibility of RNFL thickness measurements generally improves with the use of scan tracking coordinates, particularly in the temporal sector. However, small changes in the position of the scan do not significantly affect the reproducibility of optic disc parameters.

Full Text

Duke Authors

Cited Authors

  • Vizzeri, G; Bowd, C; Medeiros, FA; Weinreb, RN; Zangwill, LM

Published Date

  • January 2009

Published In

Volume / Issue

  • 18 / 1

Start / End Page

  • 81 - 87

PubMed ID

  • 19142141

Pubmed Central ID

  • 19142141

Electronic International Standard Serial Number (EISSN)

  • 1536-481X

Digital Object Identifier (DOI)

  • 10.1097/IJG.0b013e31816b3063

Language

  • eng

Conference Location

  • United States