Laminar Disinsertion From The Neural Canal Observed In Three-Dimensional Reconstruction Of Human Glaucomatous Optic Nerves

Abstract

 

Purpose:

 

To determine the frequency and extent of laminar disinsertion from the neural canal wall within three-dimensional reconstructions of glaucomatous optic nerve heads (ONH) in eyes fixed at physiologic IOP.

 

Methods:

 

14 eyes from 7 donors with clinical records documenting open angle glaucoma underwent endoscopic vitrectomy, were maintained at 10mmHg for 30 minutes with a BSS infusion, then fixed for 4 hours with 2% Glutaraldehyde/1% Paraformaldehyde. ONHs were reconstructed with a 1.5µ voxel resolution. 14 landmarks were delineated within 40 serial, radial, digital, sagittal sections. Regions of disinsertion of the lamina cribrosa were visualized within the 3D datasets.

 

Results:

 

Severity of POAG donors ranged from early pre-perimetric disease to advanced loss (Table). Disinsertion of the lamina cribrosa was visualized in 5 of 14 of eyes. The degree of disinsertion appeared greater in the posterior lamina in all eyes and the extent varied from as little as one clock hour to broad disinsertion extending into the temporal region (Figure A). While, disinsertion was usually seen in eyes with extensive visual field loss, it was also seen in some eyes with no associated field loss (Figure B).

 

Conclusions:

 

Laminar disinsertion from the neural canal is not infrequently seen in 3D reconstructions of the glaucomatous optic nerve head when fixed at physiologic IOP. Profound disinsertion was seen in one eye without associated field loss.  

 

Keywords: optic nerve • lamina cribrosa • imaging/image analysis: non-clinical