Confocal Adaptive Optics Imaging of Peripapillary Nerve Fiber Bundles: Implications for Glaucomatous Damage Seen on Circumpapillary OCT Scans.

Alfredo Dubra // Publications // Apr 01 2015

PubMed ID: 25909035

Author(s): Hood DC, Chen MF, Lee D, Epstein B, Alhadeff P, Rosen RB, Ritch R, Dubra A, Chui TY. Confocal adaptive optics imaging of peripapillary nerve fiber bundles: implications for glaucomatous damage seen on circumpapillary OCT scans. Transl Vis Sci Technol. 2015 Apr 10;4(2):12. eCollection 2015 Apr. PMID 25909035

Journal: Translational Vision Science & Technology, Volume 4, Issue 2, Apr 2015

PURPOSE To improve our understanding of glaucomatous damage as seen on circumpapillary disc scans obtained with frequency-domain optical coherence tomography (fdOCT), fdOCT scans were compared to images of the peripapillary retinal nerve fiber (RNF) bundles obtained with an adaptive optics-scanning light ophthalmoscope (AO-SLO).

METHODS The AO-SLO images and fdOCT scans were obtained on 6 eyes of 6 patients with deep arcuate defects (5 points ≤-15 db) on 10-2 visual fields. The AO-SLO images were montaged and aligned with the fdOCT images to compare the RNF bundles seen with AO-SLO to the RNF layer thickness measured with fdOCT.

RESULTS All 6 eyes had an abnormally thin (1% confidence limit) RNF layer (RNFL) on fdOCT and abnormal (hyporeflective) regions of RNF bundles on AO-SLO in corresponding regions. However, regions of abnormal, but equal, RNFL thickness on fdOCT scans varied in appearance on AO-SLO images. These regions could be largely devoid of RNF bundles (5 eyes), have abnormal-appearing bundles of lower contrast (6 eyes), or have isolated areas with a few relatively normal-appearing bundles (2 eyes). There also were local variations in reflectivity of the fdOCT RNFL that corresponded to the variations in AO-SLO RNF bundle appearance.

CONCLUSIONS Relatively similar 10-2 defects with similar fdOCT RNFL thickness profiles can have very different degrees of RNF bundle damage as seen on fdOCT and AO-SLO.

TRANSLATIONAL RELEVANCE While the results point to limitations of fdOCT RNFL thickness as typically analyzed, they also illustrate the potential for improving fdOCT by attending to variations in local intensity.