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Journal of Ophthalmology
Volume 2011 (2011), Article ID 692574, 9 pages
http://dx.doi.org/10.1155/2011/692574
Research Article

Assessing Errors Inherent in OCT-Derived Macular Thickness Maps

1Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
2Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
3Department of Ophthalmology, William Beaumont Hospital, Royal Oak, MI 48073, USA
4Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA

Received 27 January 2011; Accepted 24 June 2011

Academic Editor: Eduardo Buchele Rodrigues

Copyright © 2011 Daniel Odell et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

SD-OCT has become an essential tool for evaluating macular pathology; however several aspects of data collection and analysis affect the accuracy of retinal thickness measurements. Here we evaluated sampling density, scan centering, and axial length compensation as factors affecting the accuracy of macular thickness maps. Forty-three patients with various retinal pathologies and 113 normal subjects were imaged using Cirrus HD-OCT. Reduced B-scan density was associated with increased interpolation error in ETDRS macular thickness plots. Correcting for individual differences in axial length revealed modest errors in retinal thickness maps, while more pronounced errors were observed when the ETDRS plot was not positioned at the center of the fovea (which can occur as a result of errant fixation). Cumulative error can exceed hundreds of microns, even under “ideal observer” conditions. This preventable error is particularly relevant when attempting to compare macular thickness maps to normative databases or measuring the area or volume of retinal features.