Purpose:
Direct correlation of ocular coherence tomography (OCT) data with histology of the retina has been lacking, particularly in human retinal disease. This study is designed to refine understanding of both normal and pathological OCT data with high performance histological methods.
Methods:
A Heidelberg Spectralis OCT system was used to obtain retinal scans from collected normal human globes as well as globes from patients who suffered from retinitis pigmentosa (RP), wet and dry age-macular degeneration (AMD) and geographic atrophy (GA). The globes were resected post-mortem, fixed in 1% paraformaldehyde, 2.5% glutaraldehyde, anterior segment removed and mounted in normal saline in a spectrophotometer chamber. OCT imaging was then performed on regions of interest and data saved with landmarks. The globes were then removed, portions corresponding to regions imaged by OCT were punched out, dehydrated, embedded in eponates and histologically analyzed with computational molecular phenotyping and ultrastructural analysis.
Results:
While some data exists in the literature, a high performance correlation of OCT data with human histology has not to our knowledge been previously performed. Normal retinal tissues reflect the precise understanding of landmarks associated with OCT data and correspond with previously published results. However, pathological retinas presented a number of refinements of our understanding of OCT data including detailed evaluation of Müller cell structure and representation in pigmented bone spicules complete with pigment granules derived from the RPE in mid stage and advanced RP. Additionally, AMD findings of localized atrophy, sub-RPE drusen in AMD and pigment epithelial detachments along with interface alterations between the RPE and retina and sub-retinal deposits are described.
Conclusions:
OCT has proven invaluable in the clinic to diagnose and track disease progression. Defining precise understanding of OCT correlates with the histology of retinal structure and function in retinal degenerative diseases will assist the definition of windows of opportunity for various vision rescue strategies.
Keywords: retina • immunohistochemistry • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)