Remodeling of the connective tissue microarchitecture of the lamina cribrosa in early experimental glaucoma.

PURPOSE: To characterize the trabeculated connective tissue microarchitecture of the lamina cribrosa (LC) in terms of total connective tissue volume (CTV), connective tissue volume fraction (CTVF), predominant beam orientation, and material anisotropy in monkeys with early experimental glaucoma (EG). METHODS: The optic nerve heads from three monkeys with unilateral EG and four bilaterally normal monkeys were three dimensionally reconstructed from tissues perfusion fixed at an intraocular pressure of 10 mm Hg. A three-dimensional segmentation algorithm was used to extract a binary, voxel-based representation of the porous LC connective tissue microstructure that was regionalized into 45 subvolumes, and the following quantities were calculated: total CTV within the LC, mean and regional CTVF, regional predominant beam orientation, and mean and regional material anisotropy. RESULTS: Regional variation within the laminar microstructure was considerable within the normal eyes of all monkeys. The laminar connective tissue was generally most dense in the central and superior regions for the paired normal eyes, and laminar beams were radially oriented at the periphery for all eyes considered. CTV increased substantially in EG eyes compared with contralateral normal eyes (82%, 44%, 45% increases; P