Abstract
Abstract: :
Purpose: To further define the origin of the outer "red line" present in retinal optical coherence tomograms; to investigate a role for optical coherence tomography (OCT) in studying peripheral retinal pathology in fixed tissue specimens; to explore a possible role for OCT in the eye pathology laboratory.Methods: We studied eleven formalin–fixed caps of seven human eyes previously enucleated for choroidal melanoma. The evaluation of the "red line" consisted of the sequential, surgical elimination of the retinal pigment epithelium (RPE), Bruch’s membrane, and choroid in separate, but adjacent, areas. OCT evaluation was correlated with histological examination of each of these areas. In addition, OCT images were taken through peripheral retinal pathology present in the caps. These images were also correlated with histological examination.Results: The "red line", rather than representing a specific fixed anatomic layer or cell type, appears to be a first highly reflective optical surface. In the specimens examined the reflecting layers appeared to be composed of the RPE, Bruch’s membrane, and inner choroid. The contribution of Bruch’s membrane/inner choroidal complex was more evident than that of the RPE. Three peripheral retinal pathologies including peripheral cystoid degeneration, localized peripheral retinal detachment, and paving stone degeneration were studied and their images correlated well with their histology. The correlation of these OCT images, which to our knowledge are first reported here, with the histological counterpart of each of these common pathologies, supports the feasibility of OCT imaging of fixed tissue specimens.Conclusions: This study suggests that the outer "red line" present in OCT retinal images is not a specific indicator of a tissue layer or cell type. Rather it appears to represent a highly reflective optical surface which, when eye layers are normally configured, corresponds to the RPE/ Bruch’s membrane/ inner choroidal complex with a predominant contribution from Bruch’s membrane and inner choroid. We also demonstrate practical utility for OCT imaging of peripheral retinal pathology in fixed tissue specimens. That these OCT images correlate with findings from histological sections suggests a possible role for OCT in the eye pathology laboratory.
Keywords: imaging/image analysis: non-clinical • pathology: human • retina