Effects of ocular rotation on parapapillary retinal nerve fiber layer thickness analysis measured with spectral-domain optical coherence tomography

To evaluate the effects of ocular rotation on parapapillary retinal nerve fiber layer (RNFL) thickness measured by spectral-domain optical coherence tomography (SD-OCT). Eighty-eight normal and 205 glaucomatous eyes were studied. RNFL thickness was measured by 3D OCT. Ocular rotation angle was measured from a fundus image obtained by a non-mydriatic fundus camera equipped with 3D OCT. The average, hemi-superior, and hemi-inferior RNFL thicknesses as well as those in the 4 quadrants and the 16-segmented superotemporal (ST-1) and inferotemporal (IT-4) sectors were compared both before and after correcting for ocular rotation. Receiver operating characteristic curves and the areas under the curve (AUC) for the RNFL thicknesses were calculated on the basis of the data from glaucomatous and control eyes. The relationships between RNFL thickness and retinal sensitivity in the corresponding visual field were analyzed using a Humphrey field analyzer. Correction for ocular rotation did not affect the AUCs of the hemi-superior and hemi-inferior RNFL thicknesses. RNFL thicknesses in all of the quadrants and in ST-1 and IT-4 were significantly changed by correcting for ocular rotation. The correlations between all RNFL sectors and retinal sensitivity were not changed by correcting for the ocular rotation angle. Ocular rotation compensation affected RNFL thickness measurement with 3D OCT. However, the effect was clinically negligible in the diagnosis of glaucoma.