Three-dimensional imaging of lamina cribrosa defects in glaucoma using swept-source optical coherence tomography

Abstract

Purpose: To visualize lamina cribrosa defects using three-dimensional (3D) swept-source optical coherence tomography (SS-OCT), and to determine the factors associated with this feature.

Methods: All subjects were examined using an SS-OCT prototype system, which uses a tunable laser as a light source, operated at 100,000 Hz A-scan repetition rate in the 1050-nm wavelength. A 3D raster scan protocol consisting of 256×256 A-scans was acquired over a square area of 3 mm×3 mm centered on the optic disc. En face sectioned volume and serial en face images and orthogonal (horizontal and vertical) serial B-scans were evaluated.

Results: A total of 182 eyes of 111 patients with glaucoma and 29 healthy eyes of 26 subjects were included. Twenty full-thickness focal lamina cribrosa defects were found in 12 (6.6%) of 182 eyes with glaucoma, whereas no lamina defects were found in healthy eyes. Nine eyes (75.0%) showed 15 full-thickness lamina cribrosa defects near the margin of the lamina cribrosa, and 3 eyes showed 4 lamina defects at the margin, as if detached from the sclera. Focal lamina cribrosa defects corresponded with neuroretinal rim thinning, concurrent or previous disc hemorrhages, abnormal circumpapillary retinal nerve fiber layer thickness, and visual field defects. The presence of lamina cribrosa defects was significantly associated with longer axial length and disc hemorrhages (P=0.033 and 0.024, respectively).

Conclusions: 3D SS-OCT imaging allows visualization of the lamina cribrosa defects, which may be more prevalent in eyes with longer axial length and related to disc hemorrhages.

Keywords: glaucoma; lamina cribrosa; optical coherence tomography.