Racial variation in the structure of the lamina cribrosa and sclera within 3-D fluorescent reconstructed optic nerve heads (ONH) from normal human donor tissue

Abstract

 

Purpose

 

To examine associations between morphometric variations in the structure of the lamina cribrosa and sclera with age and race [African descent (AD), European Descent (ED)] within histologic 3-D fluorescent reconstructions of normal human donor ONHs.

 

Methods

 

The trephinated ONH and peripapillary sclera from 26 normal human donor eyes with clinical records fixed at physiologic IOP were serial sectioned using an automated microtome-based system that yielded serial fluorescent images of the block face as we cut through the ONH at 1μm section thickness (Downs JC et al, ISER 2010). We aligned and stacked the autofluorescent images to create a 3-D ONH reconstruction with a voxel resolution of 1x1x1μm and then delineated the ONH and peripapillary sclera according to guidelines set for histomorphometric ONH delineations (Downs, Yang, et al. IOVS 2007). Associations with age and race and significant interactions were determined for key morphometric parameters using mixed effects models with generalized estimating equations.

 

Results

 

In adjusted models (table), the peripapillary sclera (p=0.0032) and lamina cribrosa (p=0.00026) were thinner in eyes from AD donors, which also exhibited a deeper posterior laminar insertion (PLI) (p-value: 0.026). There was significant age-associated enlargement in Bruchs’ membrane opening (BMO) along with all neural canal landmarks within AD group (Figure).

 

Conclusions

 

Significant variations in ONH ultrastructure associated with age and across racial groups are present, which are likely to result in different biomechanical behavior with age and between racial groups.

 

 

 

Keywords: 629 optic nerve • 638 pathology: human • 577 lamina cribrosa