Enhanced Depth Imaging Spectral-domain Optical Coherence Tomography

Purpose: To describe a method to obtain images of the choroid using conventional spectral-domain (SD) optical coherence tomography (OCT) and to evaluate choroidal thickness measurements using these images.

Design: Observational case series.

Methods: The images were obtained by positioning the SD OCT device close enough to the eye to obtain an inverted representation of the fundus in healthy volunteers who did not have pupillary dilation. Seven sections, each comprised of 100 averaged scans, were obtained within a 5- x 15-degree rectangle centered on the fovea. The choroidal thickness under the fovea in each image was measured by independent observers.

Results: The choroidal thickness could be evaluated in every subject's choroidal image. The mean choroidal thickness under the fovea was 318 microm in the right eye and 335 microm in the left eye. The choroidal thickness showed a high correlation in both eyes (r = 0.82; P < .001). The correlation between the measurements performed by the independent observers was highly significant (right eye, r = 0.93; left eye, r = 0.97; P < .001 for both).

Conclusions: This method provides detailed, measurable images from the choroid, a structure that heretofore has been difficult to image in clinical practice.