Purchase this article with an account.
C. A. Curcio, J. D. Messinger, R. F. Spaide; Thickness of Chorioretinal Layers Measured in Macula-Wide High-Resolution Histological Sections. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2286.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To assist the interpretation of clinical spectral domain optical coherence tomography (SD-OCT) by providing high-resolution light microscopic images of human macular cross-sections and measurements of chorioretinal layers; to help disambiguate a combined signal from the ganglion cell (GC) and inner plexiform (IP) layers and from the outer plexiform (OP) and outer nuclear (ON) layers.
Eyes of older donors were preserved in mixed aldehydes within 6 hr of death. Grossly normal maculas were excised as full thickness eye wall punches with an 8.5 mm trephine. Punches were post-fixed in osmium and paraphenylenediamine for neutral lipids, push-processed via microwave for epoxy resin embedding, sectioned at 0.8 µm thickness, and stained with toluidine blue. In sections through the foveola from the optic nerve head to 3 mm temporal, thicknesses of 21 layers and sub-layers were measured at 25 standard locations. Distances are expressed relative to the foveal center. Results were compared to SD-OCT scans of normal eyes.
Our histological preparation reveals details not easily appreciated in standard paraffin sections, including cone pedicle synaptic complexes, unique features of the central bouquet of foveal cones, and early age-related deposits in Bruch’s membrane. Layers and structures visible histologically were not necessarily differentiated in the SD-OCT scans. The GCL and IPL are combined in one band of moderate reflectivity (GCL+IPL), and the OPL and ONL (OPL+ONL) are combined in another band of low reflectivity. The proportion of the combined layers occupied by component layers varies considerably with distance, so that adjacent layers cannot be divided proportionally (e.g., a 50% split) across the macula. For example, the GCL+IPL is thickest (90-100 µm) at 0.8-1.0 mm, and the IPL proportion varies between 20% near the foveal center and 60% at 3 mm. The proportion of OPL+ONL occupied by the component layers also varies, in a complex, yet eccentricity-dependent manner.
SD-OCT bands can combine signals from adjacent major retinal layers. Thickness data from all chorioretinal layers across wide macular swaths will be useful for interpreting clinical SD-OCT images, developing a mathematical transfer function to transform histologic measurements of layer thicknesses to match those found during SD-OCT examination, and providing benchmarks for next-generation tomographic imaging.
This PDF is available to Subscribers Only