Purpose
To evaluate optic nerve head drusen (ONHD) using optical coherence tomography (OCT) methodologies that are capable of deeper tissue penetration and to determine associated retinal nerve fiber layer (RNFL) changes.
Methods
Eyes with ONHD unassociated with systemic disease were examined with enhanced depth imaging (EDI)-OCT, swept source OCT, and fundus autofluorescence. The greatest diameter, location and depth of each ONHD were determined and correlated with RNFL thickness measured using spectral domain OCT. Sectors of abnormal RNFL thickness were considered to be present if the thickness in that region was one percentile or less of the normographic values.
Results
Twenty-three eyes of 14 patients with ONHD were evaluated. The mean age was 64.1 years, and 8 were female. EDI-OCT and swept source OCT showed multiple ONHD of various sizes at different levels, all located anterior to the lamina cribrosa. The drusen were round, oval, or polymorphic regions of lower reflectivity that were bordered by hyperreflective material, and in 10 eyes (43.5%) there were internal hyperreflective foci. The mean±SD (range) diameter of the ONHD was 649.7 ± 352.3μm (range 226 to 1237 μm). There was a significant positive correlation between the diameter of the ONHD and the number of sectors of abnormal RNFL thickness (r = 0.45, P = 0.04), and a significant negative correlation between the diameter of the ONHD and the RNFL thickness (r = -0.48, P = 0.02). Eyes with ONHD located in the middle of the optic nerve did not have abnormal RNFL thicknesses, whereas 75% (15/20) of eyes with ONHD located on the side of the optic nerve canal had abnormal RNFL thickness (P = 0.03).
Conclusions
OCT imaging capable of deeper tissue penetration in eyes with ONHD showed size, location, and composition details not previously available using older imaging technologies. The size and location of the ONHD were directly correlated with associated RNFL abnormalities.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
504 drusen •
627 optic disc