In:
Ophthalmic Surgery, Lasers and Imaging Retina, SLACK, Inc., Vol. 46, No. 8 ( 2015-09), p. 872-879
Abstract:
To evaluate scaling and measurement differences between flash and scanning laser fundus images. PATIENTS AND METHODS: The authors analyzed fundus autofluorescence images of patients with geographic atrophy secondary to age-related macular degeneration imaged with both 30º confocal scanning laser ophthalmoscope (cSLO) and 50º flash fundus camera (FFC). Multiple vessel-crossing points served as landmarks. RESULTS: The mean (± SD; range) scaling factor between cSLO and FFC images (by GRADOR) for the horizontal dimension was 1.217 (± 0.0487; 1.0474-1.272) versus 1.138 (± 0.0311; 1.0841-1.193) for the vertical dimension. The mean percentage difference between horizontal and vertical scaling factors was 7.48 (± 2.29; 2.30–10.70). Refractive error (focus) and aperture size (or field of view of the image) were positively correlated and aspect ratio was negatively correlated with landmark pair measurements. CONCLUSION: Inherent image-scaling differences between fundus autofluorescence imaging systems are not restricted to simple pixel-to-millimeter calibration variances, but appear to vary depending on measurement orientation. Differences should be considered when comparing measurements obtained using different imaging systems, particularly for clinical trials. [ Ophthalmic Surg Lasers Imaging Retina . 2015;46:872–879.]
Type of Medium:
Online Resource
ISSN:
2325-8160
,
2325-8179
DOI:
10.3928/23258160-20150909-13
Language:
English
Publisher:
SLACK, Inc.
Publication Date:
2015
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