Evaluation of Optical Coherence Tomography Central Retinal Thickness Parameters for use as Anatomic Outcomes in Clinical Trials for Neovascular Age-Related Macular Degeneration

¹ Department of Ophthalmology, Doheny Retina Institute, Los Angeles, California, United States
² Department of Ophthalmology, University of Cologne, Cologne, Germany
³ Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California, United States
⁴ Department of Ophthalmology, Doheny Retina Institute, 1450 San Pablo Street - DEI 3610, Los Angeles, California, 90033, United States

^* To whom correspondence should be addressed. E-mail: sadda{at}usc.edu.

	Abstract

Purpose: To investigate the relationship between automated and manually-derived measurements of central retinal thickness from optical coherence tomography (OCT), and to determine the relationship between foveal center point (FCP) and foveal central subfield (FCS), in neovascular age-related macular degeneration (AMD). Methods: Data from 216 patients newly diagnosed with neovascular AMD, who underwent StratusOCT imaging at diagnosis, were collected. Raw StratusOCT images for each patient were analyzed using publicly available custom software entitled "OCTOR", which allows accurate manual grading of OCT B-scans. Manually-derived central retinal thickness measurements were compared to measurements obtained from automated StratusOCT analysis. Manually obtained measurements of FCP and FCS were also compared. Results: The mean (± SD) difference in thickness between automated and manually-derived FCP thickness was 7.9 µm (± 90.8 µm), but the maximum difference was 455 µm. The limits of agreement (95% confidence interval), between automated and manually obtained FCP thicknesses, were -173.7 µm (lower limit) and 189.6 µm (upper limit), with a coefficient of determination (R2) of 0.49 (p<0.001). In contrast, the R2 for manually-derived FCP and manually-derived FCS thickness was 0.94 (p<0.001), with a smaller mean (± SD) difference in thickness of 13.8 µm (± 29.8 µm). Conclusions: Manual correction of errors in automated OCT segmentation may be required to allow accurate interpretation of anatomic outcomes for clinical trials of neovascular AMD. In addition, although measurement of FCS remains preferable for assessment of central retinal thickness, accurate measurement of FCP may represent an adequate alternative when FCS is unavailable.

Key Words: age-related macular degeneration, optical coherence tomography, image analysis

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