Correlating morphometric parameters of the porcine optic nerve head in spectral domain optical coherence tomography with histological sections.

Aim To correlate morphometric parameters of the porcine optic nerve head (ONH) in spectral domain optical coherence tomography (SD-OCT) B-scans with matched histological sections. Methods Ten porcine eyes were scanned using the Spectralis SD-OCT (Heidelberg Engineering, Heidelberg, Germany) at 7 mm Hg and subsequently fixed, cryosectioned and stained with Van Giessen stain. B-scans were matched with histological sections and morphometric parameters measured on both. Results SD-OCT measurements of the Bruch membrane opening (BMO) cross-sectional diameter and the mean distance from the BMO plane to the anterior surface of the collagenous lamina cribrosa correlated strongly with matched histological measurements (r=0.80 (p=0.005) and 0.83 (p=0.003), respectively) while measurements of the mean prelaminar tissue thickness, cup cross-sectional area and neuroretinal rim cross-sectional area had lower correlation coefficients (r=0.62 (p=0.055), 0.57 (p=0.08) and 0.33 (p=0.354), respectively). SD-OCT measurement of lamina cribrosa mean cross-sectional thickness also showed a lower correlation with matched histological measurements (r=0.64, p=0.048). Conclusion A high correlation exists between SD-OCT B-scans and matched histological sections for anterior collagenous structures of the ONH, while a lower correlation exists for morphometric parameters involving the prelaminar region and lamina cribrosa thickness.