Localized Retinal Nerve Fiber Layer Defect Location among Red-free Fundus Photograph, En Face Structural Image, and Cirrus HD-OCT Maps.J Glaucoma 2019JG
While the localized RNLF defects in the en face structural images showed excellent topographic correlation with those in red-free photographs, the RNFL defect was frequently misidentified by the OCT deviation map.
To compare the location of localized retinal nerve fiber layer (RNFL) defects using red-free fundus photographs, optical coherence tomography (OCT) en face structural images, and OCT RNFL deviation and thickness maps.
We investigated the agreement of angular locations of localized RNFL defects. Seventy localized RNFL defects were selected in red-free photographs (red-free defect). En face images and OCT deviation and thickness maps were overlaid on the corresponding red-free photographs. The proximal/distal angular locations and angular width of the red-free defects were compared to those of en face structural images (en face defect) and OCT RNFL deviation (deviation map defect) and thickness maps (thickness map defect).
Among 70 eyes with red-free defects, 13 (18.6%), 1 (1.4%), and 0 (0%) defects were misidentified by the OCT deviation map, thickness map, and en face image, respectively. There were no significant differences among red-free defects, en face defects, and OCT thickness map defects in the angular width and proximal/distal angular locations. The angular widths were significantly greater in OCT RNFL deviation maps compared to those of other imaging modalities. The correlation coefficients of angular width and locations between the red-free defect and en face defect were significantly higher than those between the red-free defect and OCT map defects (all, P<0.001).
Localized RNFL defects detected in red-free photographs showed highest topographic correlation with defects detected in OCT en face images. En face structural images may aid in identifying the localized RNFL defects in glaucomatous eyes.